Catalysts and processes for hydrogen storage based on formate-bicarbonate equilibrium in aqueous media

Abstract

The present invention relates to the use of an isolated or non-isolated (in situ generated) catalyst comprising a central metal M and at least one strong sigma donor ligand selected from NHC N-heterocyclic carbene ligands and Pws water-soluble phosphine ligands, wherein the storage of hydrogen and the release of hydrogen is based on a formate-bicarbonate equilibrium, wherein M is a metal selected from non-platinum transition metals, p-block metals and f-block metals, NHC is a N-heterocyclic carbene ligand, Pws is a water-soluble phosphine ligand, in a process for storing hydrogen and / or in a process for releasing hydrogen. The present invention also relates to a process for a hydrogen storage system and a hydrogen release system, wherein the storage of hydrogen is carried out by hydrogenation of bicarbonate in an aqueous medium in the presence of a catalyst as described in the specification, CO-free x The release of hydrogen of the by-product is carried out by decomposition of formate in an aqueous medium in the presence of a catalyst as described in the specification; and wherein preferably the storage of hydrogen and the release of hydrogen is carried out in a single system with the same catalyst.

Description

[0001] This invention relates to the use of separated or non-separated (in-situ generated) catalysts comprising a central metal M and at least one strong σ-donor ligand in processes for storing hydrogen and / or for releasing hydrogen, wherein the strong σ-donor ligand is selected from NHCN-heterocyclic carbene ligands and Pws water-soluble phosphine ligands, wherein hydrogen storage and release are based on a formate-bicarbonate equilibrium, wherein M is a metal selected from non-platinum transition metals, p-block metals, and f-block metals, NHC is an N-heterocyclic carbene ligand, and Pws is a water-soluble phosphine ligand. The invention also relates to a process for hydrogen storage and release systems, wherein hydrogen storage is carried out by hydrogenation of bicarbonate in an aqueous medium in the presence of a catalyst as described in the specification; CO-free. x The release of hydrogen as a byproduct is achieved by decomposing the formate in an aqueous medium in the presence of a catalyst as described in the specification; and preferably, the storage and release of hydrogen are carried out in a single system using the same catalyst. Background Technology

[0002] The demand for hydrogen storage is growing. Hydrogen, as a feedstock, fuel, and energy carrier, can play a vital role in achieving decarbonization goals. Furthermore, in the long term, hydrogen can also be seen as a flexible energy storage option: various alternative energy sources (solar, geothermal, wind, biomass, etc.) can be used to produce hydrogen, and the storage and subsequent release of hydrogen can balance the fluctuations in alternative energy production.

[0003] However, storing hydrogen presents several challenges. Therefore, in addition to hydrogen storage based on physical principles, there is a growing interest in storing hydrogen through chemical processes. Chemical hydrogen storage systems encompass schemes for storing and releasing hydrogen based on chemical processes.

[0004] One example is the scheme of chemically bonding hydrogen to a metal in the form of metal hydrides (e.g., MgH2, MgH2-LiAlH4, MgH2-LiBH4, FeTiH2). The drawback of this scheme is that, due to the strong chemical bond between the metal and hydrogen, releasing the hydrogen requires high temperatures. Repeating this process several times can lead to adverse changes in the structure of the stored metal.

[0005] Another example is the scheme where the hydrogen atom is covalently bonded to the central atom in the coordinated hydride complex, and an additional metal ion stabilizes the complex. The most well-known examples are, for instance, compounds LiBH4 and LiAlH4. This scheme can be considered to offer a significantly higher hydrogen storage capacity than metal hydrides; however, the reversibility of these compounds is problematic. Furthermore, the release of hydrogen cannot be described as a single-step process in many cases.

[0006] Liquid organic hydrogen supports (LOHCs) are compounds that primarily contain hydrogen-poor unsaturated or aromatic functional groups. Therefore, these compounds can be saturated with hydrogen in the presence of a suitable catalyst, and subsequently, hydrogen can be released from the resulting compound, also in the presence of the catalyst. Examples of LOHCs are toluene / methylcyclohexane, dibenzyltoluene / perhydrodibenzyltoluene, and the bicarbonate / formate system used in this invention. These systems exhibit significant hydrogen storage capacity, and hydrogen can be stored for extended periods at ambient temperature and pressure with minimal loss.

[0007] In a class of chemical hydrogen storage systems based on organic hydrogen carriers, hydrogen storage and hydrogen release require different conditions (e.g., auxiliary materials or different catalysts), and the two processes, which can be considered irreversible in themselves, form a complete system, and together they can achieve hydrogen storage and hydrogen release.

[0008] A specific category of chemical hydrogen storage systems is those in which the catalytic hydrogenation of a hydrogen-poor storage medium to a hydrogen-rich compound (charging step) and the dehydrogenation under conditions of reduced hydrogen pressure and / or increased temperature (discharging step) proceed in a reversible reaction within the same device in the presence of the same catalyst. Such systems are referred to herein as chemical hydrogen accumulators, or simply hydrogen accumulators.

[0009] Therefore, in the latter case, it is required that both hydrogenation (hydrogen storage) and dehydrogenation (hydrogen release) be efficiently catalyzed by the same catalyst, which can be a heterogeneous catalyst or a homogeneous catalyst.

[0010] Furthermore, it is advantageous if the hydrogen accumulator's cyclic charging and discharging of hydrogen does not require the continuous or cyclic addition of any auxiliary materials (such as acids or alkalis). Overall, the operation of chemical hydrogen accumulators is very similar to that of electrical storage devices.

[0011] As mentioned above, hydrogen accumulators must involve reversible hydrogenation / dehydrogenation reactions, where dynamic chemical equilibrium is not particularly favorable to either reactant. A bicarbonate / formate equilibrium in aqueous solution is well-suited for this purpose. HCO3 – (aq) + H 2(aq) HCO2 – (aq) + H2O (l)。

[0012] Although aqueous alkali metal formate solutions have relatively low hydrogen capacity, they offer significant advantages for developing such hydrogen storage systems compared to other hydrogen storage methods due to their extremely low safety risks.

[0013] During the operation of a hydrogen storage device based on a bicarbonate-formate equilibrium, the reaction of bicarbonate may produce CO2 according to the following equation: 2HCO3 - = CO3² - + CO2 + H2O The extent of this side reaction is highly dependent on the concentration of bicarbonate and cations, the catalyst used for hydrogen storage, and the reaction temperature. However, under adverse conditions, the CO2 concentration can reach up to 30% of the volume of the gas stream supplied by the accumulator. This leads to the loss of storage material and may inhibit the use of the stored hydrogen in the fuel cell. Therefore, it can be seen that the CO2 generated during the discharge of the accumulator must be minimized (eliminated) by appropriately selecting the catalyst, formate, and accumulator operating conditions.

[0014] The use of Pd / C formate dehydrogenation in aqueous systems was first proposed by Wrighton et al. (Stalder, CJ; Chao, S.; Summers, DP; Wrighton, MS) J. Am. Chem. Soc 1983, 105 ( 20 ),6318–6320. https: / / doi.org / 10.1021 / ja00358a026.), which was subsequently studied by Sasson et al. (Wiener, H.; Sasson, Y.; Blum, J.). J. Mol. Catal 1986, 35 ( 3) , 277–284. https: / / doi.org / 10.1016 / 0304-5102(86)87075-4.). The first detailed study on the use of water-soluble Rh(I), Ru(II) and Ir(I) complexes as catalysts for the hydrogenation of bicarbonate in aqueous solution (without additives such as amines) was published in 1999 (Joó, F.; Laurenczy, G.; Nádasdi, L.; Elek, J.). Chem. Commun 1999, No. 11 , 971–972. https: / / doi.org / 10.1039 / a902368b. Furthermore, the homogeneous catalytic hydrogenation of bicarbonate suspension to formate in a phase-transfer catalytic toluene / water biphase reaction system is described (Rebreyend, C.; Pidko, EA; Filonenko, GA). Green Chem2021, 23, 8848–8852; https: / / doi.org / 10.1039 / D1GC02246F. This was proposed by Sasson et al. in 1986 (Zaidman, B.; Wiener, H.; Sasson, Y.). Int. J. Hydrog. Energy 1986, 11 ( 5 ), 341–347. https: / / doi.org / 10.1016 / 0360-3199(86)90154-0.) Aqueous solutions of HCO2K are widely used as hydrogen storage materials.

[0015] Plietker et al. described a catalyst using the [RuCl(PNNP)(acetonitrile)]PF6 complex in the presence of DBU (1,8-diazabicyclo[5.4.0]undec-1-ene) as a basic additive (Hsu, S.-F.; Rommel, S.; Eversfield, P.; Muller, K.; Klemm, E.; Thiel, WR; Plietker, B.). Angew. Chem. Int. Ed 2014, 53 ( 27 (7074–7078. https: / / doi.org / 10.1002 / anie.201310972.) A hydrogen storage device. According to their scheme, when the loading reaction (i.e., hydrogenation of carbon dioxide / bicarbonate) is complete (indicated by the cessation of pressure changes), the reactor is cooled to room temperature and purged with nitrogen. The resulting solution (DBU formate in toluene) can be stored at room temperature for several days and decomposes into a gaseous mixture of H2 and CO2 when heated to 100°C at atmospheric pressure, while recovering DBU. This hydrogen storage / release cycle is repeated five times with no significant changes in the discharge rate and the amount of H2 released. According to the cited publication, the hydrogen storage device requires not only the addition of H2 but also the addition of CO2 to start each cycle. Furthermore, due to a large excess of CO2, only about 15% of the CO2 used is converted to DBU formate, with the remainder being emitted at the end of the hydrogenation step.

[0016] Recently, Beller et al. described a Mn(I)-clamp-type complex that can undergo CO2 hydrogenation and formate dehydrogenation in H2O / THF solution in the presence of potassium lysine (LysK) (Wei, D.; Sang, R.; Sponholz, P.; Junge, H.; Beller, M.). Nat. Energy 2022, 7 ( 5(438–447. https: / / doi.org / 10.1038 / s41560-022-01019-4.). In the cited publication, various [MnBr(CO)2(PNP)] complexes are described as active in both CO2 hydrogenation and formic acid decomposition in a water / THF mixture. In a catalyst stability study over multiple cycles in the presence of the potassium salt of lysine (LysK), 2,000,000 catalytic cycles (TON) were observed during CO2 hydrogenation, and 600,000 TON were observed during formic acid dehydrogenation. Dehydrogenation was carried out at 90 °C and atmospheric pressure, while hydrogenation was carried out at 85 °C and 80 bar at an initial H2 pressure. The operation of the hydrogen accumulator was initiated by formic acid dehydrogenation in the presence of an equivalent amount of LysK. At the end of this step, the gas phase was evacuated and analyzed, while the solution phase was hydrogenated. LysK allows over 99.9% of the CO2 produced during formic acid dehydrogenation to be retained (internal carbon dioxide capture). The hydrogen storage and release steps can be repeated between cycles without replenishing CO2 (or other components). The operation of the hydrogen accumulator requires an amount of lysine equivalent to the formic acid concentration obtained in the hydrogenation step. The hydrogen accumulator operates at a scale of 90.0 mmol for 10 charge / discharge cycles, i.e., hydrogenation / dehydrogenation cycles, without replacing the reaction mixture.

[0017] Cao et al. have developed an all-aqueous hydrogen storage device based on HCO2K / HCO3K equilibrium under pressurized H2 and pressureless conditions using heterogeneous catalysis (Bi, Q.-Y.; Lin, J.-D.; Liu, Y.-M.; Du, X.-L.; Wang, J.-Q.; He, H.-Y.; Cao, Y.). Angew. Chem. Int. Ed 2014, 53 ( 49(13583–13587. https: / / doi.org / 10.1002 / anie.201409500.). This catalyst comprises Pd nanoparticles on a reduced graphene oxide (rGO) support, which has been found to be an active and robust catalyst for the hydrogenation of bicarbonate and the dehydrogenation of formate. HCO2K is far superior to Na-, Li-, or NH4-formates in terms of reactivity and stability. At a pressure of P(H2) = 40 bar, 7088 TON (94.5% bicarbonate conversion) was achieved during the hydrogenation of HCO3K in 5 mL of a 4.8 M aqueous solution containing 9.6 μmol Pd. After depressurization at 25 °C, dehydrogenation was performed by heating the resulting formate solution to 80 °C, yielding H2 gas within 40 minutes, with near-complete formate conversion. This charge / discharge cycle was repeated six times without any impairment to the hydrogen accumulator performance. Furthermore, even at high HCO2K concentrations (>8M) and temperatures (>150°C), only trace amounts of CO2 (<0.05% by volume) are produced. No formate decomposition occurs at or below 30°C, allowing the H2 production rate to be controlled by varying the temperature of the reaction mixture. According to the cited publication, 5 liters of 4.8M HCO2K solution can produce enough H2 to fuel a 1kW fuel cell, provided that continuous regeneration or replenishment of the enriched formate solution can be ensured.

[0018] Recently, in Acetobacter wrasse ( Acetobacterium woodii A hydrogen-dependent CO2 reductase (HDCR) enzyme complex was identified that requires hydrogen to produce formic acid and simultaneously dehydrogenates HCO2H to a mixture of H2 and CO2 in an anaerobic atmosphere without H2 (Schuchmann, K.; Müller, V.). Science 2013, 342 ( 6164 ), 1382–1385. https: / / doi.org / 10.1126 / science.1244758.). Müller et al. designed a method using resting Acetobacter wulliganella ( A. woodii Cell cultures were used as a substitute for isolated HDCR enzymes in biocatalytic hydrogen storage devices (Schwarz, FM; Moon, J.; Oswald, F.; Müller, V.). Joule 2022, 6 ( 6(1304–1319. https: / / doi.org / 10.1016 / j.joule.2022.04.020.). According to their protocol, formic acid formation and H2 release occur in the same bioreactor, and the direction of the process is regulated by alternating the purge gas composition between a daytime composition of 45% H2, 45% CO2, and 10% N2 and a nighttime composition of 100% N2. During the “nighttime” (16 hours), the formic acid concentration decreases from 28 mM to 4.9 mM. The H2 storage / release cycle is repeated for 15 days (360 hours in total).

[0019] US Patent No. 4067958 describes a process for producing hydrogen from a fuel gas containing carbon monoxide and nitrogen or methane. The fuel gas is passed through an aqueous solution containing sodium carbonate or potassium carbonate and / or sodium bicarbonate or potassium bicarbonate at temperatures of 400-600°F (204-315°C) and pressures of 20-150 atm to produce the corresponding formate. The formate solution is then catalytically decomposed to form hydrogen and carbonates and / or bicarbonates. The cited patent document also describes an apparatus for carrying out this process. The catalyst used may be a transition metal, its oxide, or its sulfide on an alkali-resistant support.

[0020] US Patent No. 20120321550 discloses in detail mononuclear transition metal complexes that can be used in hydrogen storage processes. The cited document describes the release of hydrogen from an alcohol, followed by the recovery of the starting alcohol from the resulting aldehyde using hydrogenation via a catalyst-like process. Furthermore, HCO2H / HCO2 - / CO2 / HCO3 - Equilibrium has been successfully applied to these systems. Due to the pH sensitivity of the ligands, a key issue in this system is maintaining a constant pH. Although the formate / bicarbonate cycle plays a role in the systems described in the cited patent documents, the family of catalysts used has a different structure than the catalysts described in this invention. In the catalysts of the cited documents, one of the ligands comprises two separate aromatic rings, each linked to a central metal via either a carbon atom or a carbon atom and a nitrogen atom.

[0021] Romero et al. [Romero, EA et al. Nature Catalysis 1(10), 743-747(2018)] described Cu complexes that catalyze the hydrogenation of CO2 in tetrahydrofuran (THF) solvent in the presence of a Lewis acid-base pair [typically B(C6F5)3 and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)] . Specific examples include Cu complexes with one ligand being BH4 -The other ligand is NHC or a cyclic (alkyl) (amino) carbene. However, the system for hydrogenation according to the cited document differs from the formate-bicarbonate equilibrium-based system according to the present invention.

[0022] US Patent No. 9556211 B2 describes a catalyst for the dehydrogenation of formic acid and the hydrogenation of CO2 in an aqueous medium. The catalyst is a metal complex with a central atom of Ir, Fe, Rh, or Ru, and ligands comprising carbonyl groups, hydrides, and tertiary phosphine groups. In embodiments of the cited document, only Ir complexes are included.

[0023] In their publication [Gonsalvi, L. et al. Homogeneously Catalyzed CO2 Hydrogenation to Formic Acid / Formate with Non-precious Metal Catalysts (2021)], Gonsalvi et al. summarized non-precious metal catalysts that had been successfully used up to the time of publication of the cited publication for the hydrogenation of CO2 or bicarbonates to formic acid or formate. The cited document describes various complexes of Fe, Co, Ni, Cu, Mn, Re, Mo, and W, but these are different from the complexes used in this invention.

[0024] Patent document DE102006030449 discloses a device for reversible hydrogen storage. This device is based on hydrogen capture and release. In the presence of hydrogen and a ZnO or ZnO / TiO2 catalyst, hydrogen is captured by reducing potassium carbonate and / or potassium bicarbonate in an aqueous solution to potassium formate using an electric current. Hydrogen release is carried out from an aqueous solution of potassium formate, formic acid, or a mixture thereof using a platinum or palladium catalyst.

[0025] Patent document WO2012143372 discloses a process for selectively decomposing formic acid to produce hydrogen using a transition metal complex catalyst with at least one trigonal tetradentate ligand. According to the cited document, the coordinating metals are iridium, palladium, platinum, ruthenium, rhodium, cobalt, and iron. The process can be carried out at low / medium temperatures (below 100°C) and atmospheric pressure (1 bar), producing a 1:1 H2:CO2 gas mixture. The resulting gas mixture has a carbon monoxide content below the threshold acceptable even for so-called H2 / O2PEM (proton exchange membrane) fuel cells. The catalyst structure described in the cited document differs from the structure of the catalyst described in this specification.

[0026] US Patent No. 10944119B2 discloses a process capable of storing and releasing hydrogen. Although the document mentions a bicarbonate-formate cycle for storing and releasing hydrogen, in the hydrogen release process, a transition metal catalyst (containing a ruthenium complex) is dissolved in an organic solvent or solvent mixture, and the resulting bicarbonate is formed in an aqueous phase separated from the catalyst-containing organic solution. Regarding the hydrogenation of the bicarbonate, it is only disclosed that this step can also be promoted using the same catalyst system as formate decomposition.

[0027] European Patent Document EP3065865B1 describes a process for producing and storing hydrogen. Hydrogen is produced by the catalytic decomposition of potassium formate in a concentrated aqueous solution, yielding a bicarbonate slurry and hydrogen. The mixture of the bicarbonate slurry and catalyst is then oxidized with oxygen or air to regenerate the catalyst. Hydrogen storage is carried out by reducing the oxidized potassium bicarbonate slurry containing the regenerated catalyst in the presence of hydrogen. The catalyst is palladium on a carbon support, thus this approach differs from that of the present invention.

[0028] International Patent No. WO2008032985A1 discloses an organometallic compound for hydrogen storage. The compound has the general formula A-(OMHm). n A metal hydride complex in which a transition metal (M) is attached to the oxygen atom of an organic molecule (A) containing a hydroxyl group. The transition metal is at least divalent, m is the valence of the metal atom minus 1, and n is an integer from 1 to 1000. Examples of organic compounds containing hydroxyl groups include ethylene glycol, trimethylene glycol, glycerol, and hydroxyl-containing aryl derivatives such as phloroglucinol. The schemes in the cited documents differ from those of the present invention because they are not based on formate-bicarbonate equilibrium.

[0029] International Patent No. WO2015040440 describes an iridium-containing catalyst with the general formula [IrCl(cod)(NHC)] + nP (n = 2, 3, or 4) or [Ir(cod)(NHC)(P)] + nP (n = 1, 2, or 3), wherein cod is 1,5-cyclooctadiene, NHC is N-heterocyclic carbene, and P is 1,3,5-triaza-7-phosphaadamantane (pta) or monosulfonated triphenylphosphine ( m tppms), trisulfonated triphenylphosphine ( m The catalysts described are suitable for the decomposition of formate in an aqueous reaction mixture to produce CO-free products. x Hydrogen gas as a byproduct, or applicable to the hydrogenation of bicarbonates.

[0030] International Patent No. WO2023275578 discloses a process for hydrogenating bicarbonates in an aqueous medium and decomposing formates in an aqueous medium to release hydrogen. The hydrogenation of bicarbonates is carried out in the presence of CO2 in a gas phase. The catalyst used for hydrogenation and hydrogen release also has the general formula [Ir(cod)(NHC)P]. a ]+ nP b An iridium-containing catalyst, wherein cod is 1,5-cyclooctadiene, NHC is N-heterocyclic carbene, and P a and P b It is 1,3,5-triaza-7-phosphadamane (PTA), monosulfonated triphenylphosphine ( m tppms) or trisulfonated triphenylphosphine ( m tppts).

[0031] Although the aforementioned iridium-containing catalysts can be used efficiently for hydrogenation / dehydrogenation in bicarbonate / formate systems on a laboratory scale, it should be noted that iridium is scarce in the Earth's crust and can only be obtained at high cost and in limited quantities, which poses a serious obstacle to its widespread industrial application.

[0032] The technical problem to be solved by the present invention The technical problem to be solved by this invention is to provide an economically advantageous and cost-effective catalyst that can be easily used in industrial-scale production, and to provide a process for a hydrogen storage system and a hydrogen release system. a) Hydrogen storage is achieved by hydrogenating bicarbonate in an aqueous medium in the presence of a catalyst, without the presence of CO. x The release of hydrogen from the byproduct is achieved by decomposing formate in an aqueous medium in the presence of a catalyst; b) wherein hydrogen storage and hydrogen release are carried out using the same catalyst, preferably in a single system.

[0033] The concept upon which this invention is based The aforementioned objectives are achieved through the following scheme based on a surprising concept: for the bicarbonate hydrogenation step providing hydrogen storage, and for the formate decomposition step providing hydrogen release, the catalyst described in this invention is used under the reaction conditions of this invention, both steps being carried out without the continuous or cyclic addition of auxiliary substances (e.g., acids or bases). Surprisingly, we have found that catalysts comprising complexes containing a metal central atom (which is a non-platinum transition metal, a p-block metal, or an f-block metal) and at least one strong σ-donor ligand (selected from N-heterocyclic carbene ligands and water-soluble phosphine ligands) are suitable for catalyzing the aforementioned reactions.

[0034] To demonstrate the surprising effects achieved by this invention, we emphasize that in complex compounds used as catalysts, replacing the metal atom constituting the central metal (especially platinum group metal atoms known to be effective in the field of catalysts) with another metal atom (especially a non-platinum group metal atom) is not an obvious option, because the effectiveness of the complex obtained by such modification as a catalyst in a given reaction system is unpredictable.

[0035] Brief Description of the Invention definition In the context of this invention, non-platinum group transition metals refer to those transition metals that do not belong to the platinum group. Examples of non-platinum group transition metals include titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, molybdenum, and yttrium.

[0036] In the context of this invention, "carbene" refers to a molecule containing a divalent neutral carbon atom. Typical carbene compounds are (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron, 1-R 1 -3-R 2 -imidazol-2-subunit, 1-R 1 -3-R 2 -imidazoline-2-subunit and 1-R 1 -3-R 2 -benzimidazole-2-subunit, where R 1 and R 2 Each is independently a straight-chain or branched alkyl, benzyl, or phenyl group having 1 to 6 carbon atoms, which is either unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms.

[0037] Examples of carbenes include N-heterocyclic carbenes (NHCs), such as 1-ethyl-3-methylimidazolium-2-ylene (emim), 1-butyl-3-methylimidazolium-2-ylene (bmim), 1-hexyl-3-methylimidazolium-2-ylene (hexmim), and 1-benzyl-3-methylimidazolium-2-ylene (Bnmim), and (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron. We note that N-heterocyclic carbenes, like phosphine ligands, are strong σ donors.

[0038] In the context of this invention, the term "NHC precursor" refers to a precursor of the NHC ligand as defined above, suitable for introducing the NHC ligand into a complex. A typical NHC precursor is a salt consisting of a protonated form of the NHC ligand and an anion, wherein the anion is, for example, a halide, acetate, dicyandiamide salt, tetrafluoroborate, hexafluorophosphate, or methanesulfonate. We note that although the salts mentioned are actually salts consisting of a protonated form of the NHC compound as defined above and an anion, in the nomenclature seen in the literature, only the anion is usually indicated. For example, NHC hydrochloride is often referred to as NHC chloride in the literature, although they refer to the same compound.

[0039] Examples of NHC precursors include (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron and 1-R 1 -3-R 2 -Imidazolium, 1-R 1 -3-R 2 -imidazolinium and 1-R 1 -3-R 2 - A salt of benzimidazolium, wherein R 1 and R 2 Each is independently a straight-chain or branched alkyl, benzyl, or phenyl group having 1 to 6 carbon atoms, which is either unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms.

[0040] Specific examples of NHC precursors include 1-ethyl-3-methylimidazolium chloride (emimCl), 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride (bmimCl), 1-hexyl-3-methylimidazolium chloride (hexmimCl), and 1-benzyl-3-methylimidazolium chloride (BnmimCl), and (1,4-diphenyl-1H-1,2,4-triazol-4-on-3-yl)(phenyl)nitron.

[0041] Water-soluble phosphine ligands are well known to those skilled in the art.

[0042] One type of these is tertiary phosphine, whose solubility in water is ensured by polar or ionic groups, i.e., they contain, for example, hydroxyalkyl, alkyl substituted with sulfonic acid, or phenyl substituted with sulfonic acid. It is known to those skilled in the art that, to achieve water solubility, a single sulfonic acid group in the molecule is sufficient, while multiple hydroxyl groups (e.g., multiple hydroxyalkyl groups) are typically required.

[0043] More specifically, one class of tertiary phosphines is sulfonated triphenylphosphine, which, due to the presence of a negatively charged sulfonic acid group, also contains a counterion (typically a Li, Na, K, or Cs ion), and is therefore chemically considered a salt. In the context of this invention, the term "Li, Na, K, or Cs salt of triphenylphosphine monosulfonated, disulfonated, or trisulfonated at the ortho position" refers to... o tppms, o tppds, o tppts), Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the meta position ( m tppms, m tppds, m tppts), and Li, Na, K or Cs salts of triphenylphosphine monosulfonated at the para position (tppts), and triphenylphosphine monosulfonated at the para position (tppts), p tppms) refers to compounds according to the following formula (1):

[0044] Equation (1) Where X in the formula 1 -X 7 The meanings are summarized in Table 1 below: Table 1

[0045] Y = Li, Na, K, or Cs.

[0046] In the context of this invention, water-soluble phosphine ligands also include O, N, or S heterocyclic compounds that, in addition to the aforementioned atoms, contain a trivalent phosphorus P(III) atom located in the ring (hereinafter referred to as cyclic tertiary phosphine). Their water solubility is ensured by strong hydrogen bonding interactions between the non-P (i.e., O, N, and S) heteroatoms and water.

[0047] In the context of this invention, non-limiting examples of "cyclic tertiary phosphine" include phosphazaadadamantane compounds, one example being 1,3,5-triaza-7-phosphaadadamantane (pta) according to formula (2):

[0048] Equation (2).

[0049] Another group of water-soluble phosphine ligands is those with the general formula R. 4 2P-bridge-PR 5 The factors affecting the water solubility of 2-phosphine are similar to those described for tertiary phosphine, under the condition that R... 4 2P and PR 5 At least one of the two groups contains a polar or ionic group that imparts water solubility to the ligand.

[0050] In the context of this invention, R 4 2P-bridge-PR 5 Non-limiting examples of 2-phosphine include compounds of formula (3):

[0051] Equation (3) In equation (3), X 1 -X 7 The meanings are summarized in Table 2 below, and m in equation (3) is an integer from 1 to 6, that is, in equation R 4 2P-bridge-PR 5 In 2, "bridge" refers to an alkylene group with 1 to 6 carbon atoms.

[0052] Table 2

[0053] Y = Li, Na, K, or Cs.

[0054] Water-soluble phosphine ligands also include cyclic compounds linked by bridging structures, such as bridged diphosphine derivatives of cyclic tertiary phosphine, i.e., so-called covalently bridged cyclic tertiary phosphine.

[0055] In the context of this invention, non-limiting examples of "covalently bridged cyclic tertiary phosphine" include compounds of formula (4):

[0056] Equation (4) In equation (4), m is an integer from 1 to 6.

[0057] In the context of this invention, "cyclodiene" should be understood as a cyclic hydrocarbon containing two double bonds.

[0058] In the context of this invention, "π-donor aromatic ligand" should be understood as a compound containing a single benzene ring, wherein the benzene ring is optionally substituted with an alkyl group. Examples of π-donor aromatic ligands include benzene and 4-isopropyltoluene. Detailed Implementation

[0059] The object of this invention is the use of a separated or non-separated (in-situ generated) catalyst comprising a central metal M and at least one strong σ-donor ligand in a process for storing hydrogen and / or in a process for releasing hydrogen, wherein the strong σ-donor ligand is selected from the group consisting of NHCN-heterocyclic carbene ligands and Pws water-soluble phosphine ligands, wherein hydrogen storage and hydrogen release are based on a formate-bicarbonate equilibrium, wherein: M can be selected from non-platinum transition metals, p-block metals, and f-block metals; NHC is an N-heterocyclic carbene ligand, preferably selected from the group consisting of: (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron, 1-R 1 -3-R 2 -imidazol-2-subunit, 1-R 1 -3-R 2 -imidazoline-2-subunit and 1-R 1 -3-R 2 -benzimidazole-2-subunit, where R 1 and R 2 Each of the following is a straight-chain or branched alkyl, benzyl or phenyl group having 1 to 6 carbon atoms, which is either unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms. Pws is a water-soluble phosphine ligand, selected from the group consisting of the following: The general formula is PR 1 R 2 R 3 Tertiary phosphine, of which R 1 R 2 and R 3 Independently, it is a straight-chain or branched alkyl or phenyl group with 1 to 5 carbon atoms, wherein the alkyl group may be substituted with an OH group or a sulfonic acid group, and the phenyl group may be substituted with an alkyl group and / or a sulfonic acid group with 1 to 6 carbon atoms, provided that R 1 R 2 and R 3 At least one of them contains an OH group or a sulfonic acid group; or cyclic tertiary phosphine; or The general formula is R 4 2P-bridge-PR 5 2-diphosphine, where R 4 and R 5 Independently, it is a straight-chain or branched alkyl or phenyl group with 1 to 5 carbon atoms, wherein the alkyl group may be substituted with an OH group or a sulfonic acid group, and the phenyl group may be substituted with an alkyl or sulfonic acid group with 1 to 6 carbon atoms. 4 2 and PR 5 2 can have the same or different meanings, provided that R 4 and R 5 At least one of them contains an OH group or a sulfonic acid group; wherein the bridging group is a straight-chain alkylene group with 1 to 6 carbon atoms, preferably methylene, ethylene, propylene, butylene, or hexylene; or Diphosphine, which contains cyclic tertiary phosphine groups bridged by covalent bonds.

[0060] Throughout this specification, unless otherwise stated, the term "catalyst" is used to include both non-separated (in-situ generated) catalysts and separated catalysts.

[0061] In one embodiment of the invention, M in the catalyst is selected from the group consisting of non-platinum transition metals, lanthanum, and tin.

[0062] In another embodiment of the invention, M in the catalyst is selected from the group consisting of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, yttrium, molybdenum, lanthanum, and tin.

[0063] In another embodiment of the invention, M in the catalyst is selected from the group consisting of non-platinum transition metals.

[0064] In another embodiment of the invention, M in the catalyst is selected from titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, yttrium, and molybdenum.

[0065] In another embodiment of the invention, M in the catalyst is lanthanum.

[0066] In another embodiment of the invention, M in the catalyst is tin.

[0067] In another embodiment of the invention, M in the catalyst is selected from titanium, vanadium, chromium, manganese, iron, cobalt, nickel, and copper.

[0068] In another embodiment of the invention, M in the catalyst is selected from manganese, iron, cobalt, nickel, and copper.

[0069] In one embodiment of the invention, the NHC in the catalyst is selected from the group consisting of: (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron, 1,3-dimethylimidazol-2-yl, 1-ethyl-3-methylimidazol-2-yl (emim), 1-methyl-3-propylimidazol-2-yl, 1-butyl-3-methylimidazol-2-yl (bmim), 1-methyl-3-pentylimidazol-2-yl, 1,3-diethylimidazol-2-yl, 1-ethyl-3-propylimidazol-2-yl, 1-ethyl-3-butylimidazol-2-yl, 1-ethyl-3-pentylimidazol-2-yl - Subunit, 1,3-dipropylimidazol-2-subunit, 1-propyl-3-butylimidazol-2-subunit, 1-propyl-3-pentylimidazol-2-subunit, 1,3-dibutylimidazol-2-subunit, 1-butyl-3-pentylimidazol-2-subunit, 1,3-dipentylimidazol-2-subunit, 1,3-diisopropylimidazol-2-subunit, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-subunit, 1-methyl-3-phenylimidazol-2-subunit, 1-ethyl-3-phenylimidazol-2-subunit, 1-propyl-3-phenylimidazol-2-subunit, 1-butyl-3-phenylimidazol-2-subunit, 1-pentyl-3-phenylimidazol-2-subunit, 1,3-diphenyl Imidazole-2-subunit, 1-benzyl-3-methylimidazol-2-subunit (Bnmim), 1-hexyl-3-methylimidazol-2-subunit (hexmim), 1,3-dimethylimidazoline-2-subunit, 1-methyl-3-ethylimidazoline-2-subunit, 1-methyl-3-propylimidazoline-2-subunit, 1-methyl-3-butylimidazoline-2-subunit, 1-methyl-3-pentylimidazoline-2-subunit, 1,3-diethylimidazoline-2-subunit, 1-ethyl-3-propylimidazoline-2-subunit, 1-ethyl-3-butylimidazoline-2-subunit, 1-ethyl-3-pentylimidazoline-2-subunit, 1,3-dipropylimidazoline-2-subunit, 1-propylimidazoline-2-subunit 1,3-Butylimidazoline-2-ylidene, 1-propyl-3-pentylimidazoline-2-ylidene, 1,3-dibutylimidazoline-2-ylidene, 1-butyl-3-pentylimidazoline-2-ylidene, 1,3-dipentylimidazoline-2-ylidene, 1,3-diisopropylimidazoline-2-ylidene, 1,3-bis(2,4,6-trimethylphenyl)imidazoline-2-ylidene, 1-methyl-3-phenylimidazoline-2-ylidene, 1-ethyl-3-phenylimidazoline-2-ylidene, 1-propyl-3-phenylimidazoline-2-ylidene, 1-butyl-3-phenylimidazoline-2-ylidene, 1-pentyl-3-phenylimidazoline-2-ylidene, 1,3-diphenylimidazoline-2-ylidene, 1,3-Dimethylbenzimidazole-2-ylene, 1-Methyl-3-ethylbenzimidazole-2-ylene, 1-Methyl-3-propylbenzimidazole-2-ylene, 1-Methyl-3-butylbenzimidazole-2-ylene, 1-Methyl-3-pentylbenzimidazole-2-ylene, 1,3-Diethylbenzimidazole-2-ylene, 1-Ethyl-3-propylbenzimidazole-2-ylene, 1-Ethyl-3-butylbenzimidazole-2-ylene, 1-Ethyl-3-pentylbenzimidazole-2-ylene, 1,3-Dipropylbenzimidazole-2-ylene, 1-Propyl-3-butylbenzimidazole-2-ylene, 1-Propyl-3-pentylbenzimidazole- 2-Idempotent, 1,3-dibutylbenzimidazole-2-imidazolium, 1-butyl-3-pentylbenzimidazole-2-imidazolium, 1,3-dipentylbenzimidazole-2-imidazolium, 1,3-diisopropylbenzimidazole-2-imidazolium, 1,3-bis(2,4,6-trimethylphenyl)benzimidazole-2-imidazolium, 1-methyl-3-phenylbenzimidazole-2-imidazolium, 1-ethyl-3-phenylbenzimidazole-2-imidazolium, 1-propyl-3-phenylbenzimidazole-2-imidazolium, 1-butyl-3-phenylbenzimidazole-2-imidazolium, 1-pentyl-3-phenylbenzimidazole-2-imidazolium, and 1,3-diphenylbenzimidazole-2-imidazolium. For the preparation of non-separated catalysts, suitable precursors of the listed NHC ligands can be used as NHC precursors.

[0070] In another embodiment of the invention, the NHC in the catalyst is selected from the group consisting of: 1-ethyl-3-methylimidazolium-2-yl (emim), 1-butyl-3-methylimidazolium-2-yl (bmim), 1-hexyl-3-methylimidazolium-2-yl (hexmim), and 1-benzyl-3-methylimidazolium-2-yl (Bnmim), and (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron.

[0071] In one embodiment of the invention, the Pws in the catalyst is selected from the group consisting of: The general formula is PR 1 R 2 R 3 Tertiary phosphine, selected from the group consisting of: P(CH2OH)3[tris(hydroxymethyl)phosphine], or Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the ortho position ( o tppms, o tppds, o tppts), Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the meta position ( m tppms, m tppds, mtppts), and Li, Na, K or Cs salts of triphenylphosphine monosulfonated at the para position (tppts), and triphenylphosphine monosulfonated at the para position (tppts), p tppms); and 1,3,5-Triaza-7-phosphaadamantane (pta).

[0072] In another embodiment of the invention, the Pws in the catalyst is selected from the group consisting of: The general formula is R 4 2P-bridge-PR 5 2 phosphine, of which PR 4 2 and PR 5 2 is independently selected from: P(CH2OH)2 (bis(hydroxymethyl)phosphino), PPh2 (diphenylphosphino), Li, Na, K, or Cs salts of diphenylphosphino monosulfonated or disulfonated at the ortho position, Li, Na, K, or Cs salts of diphenylphosphino monosulfonated or disulfonated at the meta position, and Li, Na, K, or Cs salts of diphenylphosphino monosulfonated or disulfonated at the para position; "bridge" represents an alkylene group with 1 to 6 carbon atoms; and According to the compound of formula (4):

[0073] Equation (4) In equation (4), m is an integer from 1 to 6.

[0074] In another embodiment of the invention, the Pws in the catalyst is selected from the group consisting of Li, Na, K, or Cs salts of triphenylphosphine monosulfonated, disulfonated, or trisulfonated at the meta position. m tppms, m tppds, m tppts); 1,3,5-triaza-7-phosphaadamantane (pta).

[0075] In another embodiment of the invention, the Pws in the catalyst is selected from the group consisting of tetrasulfonated 1,2-bis(diphenylphosphino)ethane (dppets), tetrasulfonated 1,3-bis(diphenylphosphino)propane (dpppts), and compounds of formula (4).

[0076] According to the embodiments, the isolated or non-isolated (in-situ generated) catalyst according to the present invention corresponds to general formula (I), (II) or (III): [M(NHC) n (Pws) p (L 1 ) q (L 2 ) r (I), or [Fe3(NHC)n' (Pws) p' (L 1 ) q' (L 2 ) r' (II) or [Co2(NHC) n" (Pws) p" (L 1 ) q" (L 2 ) r" (III) in M, NHC, and Pws are as defined above; L¹ is a negatively charged ligand, preferably selected from the group consisting of: H - F - Cl - ,Br - I - OH - BF4 - PF6 - HCO3 - (bicarbonate), HCO2 - (Formate), CH3CO2 - (Acetate), [CH3COCHCOCH3] - (Acetylacetone), cyanide, isocyanate, nitrite, nitrate, thiocyanate, isothiocyanate, SO4² - and O² - ; L² is a neutral (nonionic) ligand selected from the group consisting of: H₂O, CO (carbonyl); MeOH; dimethyl sulfoxide or acetonitrile; a 5- to 10-membered ring cyclodiene, optionally substituted with one or more substituents selected from alkyl and phenyl groups of 1 to 5 carbon atoms; a 6- to 10-carbon π-donor aromatic ligand; and In general formula (I), n, p, q and r are 0, 1, 2, 3 or 4, provided that n+p is at least 1 and n+p+q+r ≤ 8; In general formula (II), n' is 0 or 1, p' is 1, 2 or 3, q' is 0, and r' = 12-n'-q'-r'-p'; In general formula (III), n" is 0 or 1, p" is 1 or 2, q" is 0, and r" = 8-n"-q"-r"-p"; Wherein, if n, p, q, r, n', p', q', r', n", p", q" and / or r" are greater than 1, then NHC, Pws, L¹ and / or L² can be the same or different.

[0077] In general formula (I), L¹ represents a negatively charged ligand. Suitable negatively charged ligands are well known to those skilled in the art. In embodiments of the present invention, L¹ is selected from the group consisting of: H - F - Cl - ,Br - I - OH - BF4 - PF6 - HCO3 - (bicarbonate), HCO2 - (Formate), CH3CO2 - (Acetate), [CH3COCHCOCH3] - (Acetylacetone), cyanide, isocyanate, nitrite, nitrate, thiocyanate, isothiocyanate, SO4² - and O² - .

[0078] In another embodiment of the invention, in general formula (I), L¹ is H - F - Cl - ,Br - I - BF4 - PF6 - CH3CO2 - (acetate), SO4² - or O² - .

[0079] In another embodiment of the invention, in general formula (I), L¹ is H - F - Cl - ,Br - I - CH3CO2 - (acetate), SO4² - or O² - .

[0080] In another embodiment of the invention, in general formula (I), L¹ is F - Cl - ,Br - I - SO4² - or O² - .

[0081] In another embodiment of the invention, in general formula (I), L¹ is H - F - Cl- ,Br - I - or CH3CO2 - (Acetate).

[0082] In general formulas (I), (II), or (III), L² represents a neutral ligand. Suitable ligands are well known to those skilled in the art. In one embodiment of the invention, L² is selected from the group consisting of: H₂O; CO (carbonyl); MeOH; dimethyl sulfoxide or acetonitrile; a 5- to 10-membered ring cyclodiene, optionally substituted with one or more substituents selected from alkyl and phenyl groups of 1 to 5 carbon atoms; or a 6- to 10-carbon π-donor aromatic ligand.

[0083] In another embodiment of the invention, the optionally substituted 5- to 10-membered ring cyclodiene is selected from the group consisting of: 1,5-cyclodiene, cyclopentadiene, 1,2,3,4,5-pentamethylcyclopentadiene and 1,2,3,4,5-pentaphenylcyclopentadiene.

[0084] In another embodiment of the invention, the 6 to 10 carbon atom π-donor aromatic ligand is selected from the group consisting of benzene and 4-isopropyltoluene.

[0085] In another embodiment of the invention, in general formula (I), (II) or (III), L² is CO, H2O, MeOH, CH3CN or dimethyl sulfoxide.

[0086] In another embodiment of the present invention, L² is CO, H₂O, MeOH, or CH₃CN.

[0087] In another embodiment of the invention, L² is CO or H₂O.

[0088] In another embodiment of the invention, in general formula (I), n and p are 0, 1, or 2; q is 0, 1, 2, 3, or 4; and r is 0, 1, 2, 3, or 4, provided that n+p is at least 1. Preferably, n+p+q+r ≤ 8.

[0089] In another implementation, n+p in general formula (I) is 1, 2, or 3. In another implementation, n+p+q+r ≤ 6.

[0090] In another embodiment of the invention, in general formula (I), (II) or (III), NHC is selected from the group consisting of: (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl) nitron, 1,3-dimethylimidazol-2-yl, 1-ethyl-3-methylimidazol-2-yl (emim), 1-methyl-3-propylimidazol-2-yl, 1-butyl-3-methylimidazol-2-yl (bmim), 1-methyl-3-pentylimidazol-2-yl, 1,3-diethylimidazol-2-yl, 1-ethyl-3-propylimidazol-2-yl, 1-ethyl-3-butylimidazol-2-yl, 1-ethyl-3-pentylimidazol-2-yl, 1,3-dipropylimidazolium -2- imidazole, 1-propyl-3-butylimidazol-2-imidazole, 1-propyl-3-pentylimidazol-2-imidazole, 1,3-dibutylimidazol-2-imidazole, 1-butyl-3-pentylimidazol-2-imidazole, 1,3-dipentylimidazol-2-imidazole, 1,3-diisopropylimidazol-2-imidazole, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-imidazole, 1-methyl-3-phenylimidazol-2-imidazole, 1-ethyl-3-phenylimidazol-2-imidazole, 1-propyl-3-phenylimidazol-2-imidazole, 1-butyl-3-phenylimidazol-2-imidazole, 1-pentyl-3-phenylimidazol-2-imidazole, 1,3-diphenylimidazol-2-imidazole, 1 Benzyl-3-methylimidazolium-2-ylene (Bnmim), 1-hexyl-3-methylimidazolium-2-ylene (hexmim), 1,3-dimethylimidazolium-2-ylene, 1-methyl-3-ethylimidazolium-2-ylene, 1-methyl-3-propylimidazolium-2-ylene, 1-methyl-3-butylimidazolium-2-ylene, 1-methyl-3-pentylimidazolium-2-ylene, 1,3-diethylimidazolium-2-ylene, 1-ethyl-3-propylimidazolium-2-ylene, 1-ethyl-3-butylimidazolium-2-ylene, 1-ethyl-3-pentylimidazolium-2-ylene, 1,3-dipropylimidazolium-2-ylene, 1-propyl-3-butylimidazolium 1,3-dibutylimidazoline-2-ylene, 1-propyl-3-pentylimidazoline-2-ylene, 1,3-dibutylimidazoline-2-ylene, 1-butyl-3-pentylimidazoline-2-ylene, 1,3-dipentylimidazoline-2-ylene, 1,3-diisopropylimidazoline-2-ylene, 1,3-bis(2,4,6-trimethylphenyl)imidazoline-2-ylene, 1-methyl-3-phenylimidazoline-2-ylene, 1-ethyl-3-phenylimidazoline-2-ylene, 1-propyl-3-phenylimidazoline-2-ylene, 1-butyl-3-phenylimidazoline-2-ylene, 1-pentyl-3-phenylimidazoline-2-ylene, 1,3-diphenylimidazoline-2-ylene, 1,3-Dimethylbenzimidazole-2-ylene, 1-Methyl-3-ethylbenzimidazole-2-ylene, 1-Methyl-3-propylbenzimidazole-2-ylene, 1-Methyl-3-butylbenzimidazole-2-ylene, 1-Methyl-3-pentylbenzimidazole-2-ylene, 1,3-Diethylbenzimidazole-2-ylene, 1-Ethyl-3-propylbenzimidazole-2-ylene, 1-Ethyl-3-butylbenzimidazole-2-ylene, 1-Ethyl-3-pentylbenzimidazole-2-ylene, 1,3-Dipropylbenzimidazole-2-ylene, 1-Propyl-3-butylbenzimidazole-2-ylene, 1-Propyl-3-pentylbenzimidazole-2-ylene - Subunits, 1,3-dibutylbenzimidazole-2-subunits, 1-butyl-3-pentylbenzimidazole-2-subunits, 1,3-dipentylbenzimidazole-2-subunits, 1,3-diisopropylbenzimidazole-2-subunits, 1,3-bis(2,4,6-trimethylphenyl)benzimidazole-2-subunits, 1-methyl-3-phenylbenzimidazole-2-subunits, 1-ethyl-3-phenylbenzimidazole-2-subunits, 1-propyl-3-phenylbenzimidazole-2-subunits, 1-butyl-3-phenylbenzimidazole-2-subunits, 1-pentyl-3-phenylbenzimidazole-2-subunits, and 1,3-diphenylbenzimidazole-2-subunits; Pws selects from the following groups: The general formula is PR 1 R 2 R 3 Tertiary phosphine, selected from the group consisting of: P(CH2OH)3[tris(hydroxymethyl)phosphine], or Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the ortho position ( o tppms, o tppds, o tppts), Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the meta position ( m tppms, m tppds, m tppts), and Li, Na, K or Cs salts of triphenylphosphine monosulfonated at the para position (tppts), and triphenylphosphine monosulfonated at the para position (tppts), p tppms); and 1,3,5-Triaza-7-phosphaadamantane (pta); The general formula is R 4 2P-bridge-PR 5 2 phosphine, of which PR 4 2 and PR 52 is independently selected from: P(CH2OH)2 (bis(hydroxymethyl)phosphino), PPh2 (diphenylphosphino), Li, Na, K, or Cs salts of diphenylphosphino monosulfonated or disulfonated at the ortho position, Li, Na, K, or Cs salts of diphenylphosphino monosulfonated or disulfonated at the meta position, and Li, Na, K, or Cs salts of diphenylphosphino monosulfonated or disulfonated at the para position; and Compounds of formula (4): (4), Where m is an integer from 1 to 6; L¹ is selected from the following groups: H - F - Cl - ,Br - I - OH - BF4 - PF6 - HCO3 - (bicarbonate), HCO2 - (Formate), CH3CO2 - (Acetate), [CH3COCHCOCH3] - (Acetylacetone), cyanide, isocyanate, nitrite, nitrate, thiocyanate, isothiocyanate, SO4² - and O² - ; L² can be CO, H₂O, MeOH, CH₃CN, or dimethyl sulfoxide.

[0091] In another embodiment of the invention, in a catalyst of general formula (I), (II) or (III) NHC is 1-ethyl-3-methylimidazolium-2-yl (emim), 1-butyl-3-methylimidazolium-2-yl (bmim), 1-hexyl-3-methylimidazolium-2-yl (hexmim), 1-benzyl-3-methylimidazolium-2-yl (Bnmim) or (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl) nitrogen hybrid (nitron); Pws is a Li, Na, K, or Cs salt of triphenylphosphine monosulfonated, disulfonated, or trisulfonated at the meta position. m tppms, m tppds, m tppts), or 1,3,5-triaza-7-phosphaadamantane (pta), tetrasulfonated 1,2-bis(diphenylphosphino)ethane (dppets), tetrasulfonated 1,3-bis(diphenylphosphino)propane (dpppts) or compounds of formula (4): (4), Where m is an integer from 1 to 6, L¹ is H - F - Cl - ,Br - I - CH3CO2 - (acetate), SO4² - or O² - ;and L² can be CO, H₂O, MeOH, CH₃CN, or dimethyl sulfoxide.

[0092] In another embodiment of the invention, in a catalyst of general formula (I), (II) or (III) NHC is 1-ethyl-3-methylimidazolium-2-yl (emim), 1-butyl-3-methylimidazolium-2-yl (bmim), 1-hexyl-3-methylimidazolium-2-yl (hexmim), 1-benzyl-3-methylimidazolium-2-yl (Bnmim) or (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl) nitrogen hybrid (nitron); Pws is a Li, Na, K, or Cs salt of triphenylphosphine monosulfonated, disulfonated, or trisulfonated at the meta position. m tppms, m tppds, m tppts), or 1,3,5-triaza-7-phosphaadamantane (pta); L¹ is Cl - ,Br - CH3CO2 - SO4² - or O² - ;and L² represents CO or H₂O.

[0093] In one embodiment of the present invention, the catalyst is a catalyst of general formula (I): [M(NHC) n (Pws) p (L 1 ) q (L 2 ) r ](I), in, M is selected from non-platinum transition metals and tin, with manganese, iron, cobalt, nickel and copper being preferred; NHC is an N-heterocyclic carbene ligand, preferably selected from the group consisting of: (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron, 1-R 1 -3-R 2 -imidazol-2-subunit, 1-R 1 -3-R 2 -imidazoline-2-subunit and 1-R 1 -3-R 2 -benzimidazole-2-subunit, where R 1 and R 2 Each is an independent straight-chain or branched alkyl or phenyl group having 1 to 5 carbon atoms, which is either unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms. Pws is a water-soluble phosphine ligand, selected from the group consisting of the following: The general formula is PR 1 R 2 R 3 Tertiary phosphine, of which R 1 R 2 and R 3 Independently, it is a straight-chain or branched alkyl or phenyl group with 1 to 5 carbon atoms, wherein the alkyl group may be substituted with an OH group or a sulfonic acid group, and the phenyl group may be substituted with an alkyl group and / or a sulfonic acid group with 1 to 6 carbon atoms, provided that R 1 R 2 and R 3 At least one of them contains an OH group or a sulfonic acid group; or The general formula is R 4 2P-bridge-PR 5 2-diphosphine, where R 4 and R 5 Independently, it is a straight-chain or branched alkyl or phenyl group with 1 to 5 carbon atoms, wherein the alkyl group may be substituted with an OH group or a sulfonic acid group, and the phenyl group may be substituted with an alkyl group and / or a sulfonic acid group with 1 to 6 carbon atoms, wherein PR 4 2 and PR 5 2 can have the same or different meanings, provided that R 4 and R 5 It contains at least one OH group or sulfonic acid group; wherein the bridging group is a straight-chain alkylene group with 1 to 6 carbon atoms, preferably methylene, ethylene, propylene, butylene or hexylene; L¹ is a negatively charged ligand, preferably selected from the group consisting of: H - F - Cl - ,Br - I - OH - HCO3 - (bicarbonate), HCO2 -(Formate), CH3CO2 - (Acetate), [CH3COCHCOCH3] - (Acetylacetone), cyanide, isocyanate, nitrite, nitrate, thiocyanate, and isothiocyanate; L² is a neutral (nonionic) ligand selected from the group consisting of: H₂O; CO (carbonyl); a 5- to 10-membered ring cyclodiene, optionally substituted with one or more substituents selected from alkyl and phenyl groups of 1 to 5 carbon atoms; a 6- to 10-carbon π-donor aromatic ligand; dimethyl sulfoxide or acetonitrile; and n, p, q, and r are 0, 1, 2, 3, or 4, provided that n+p is at least 1 and n+p+q+r ≤ 8; furthermore, if n, p, q, and / or r are greater than 1, then NHC, Pws, L¹, and / or L² may be the same or different, respectively.

[0094] For example, in formula (I), the carbene is selected from: (1,4-diphenyl-1H-1,2,4-triazol-4-onth-3-yl)(phenyl) nitron, 1,3-dimethylimidazol-2-yl, 1-ethyl-3-methylimidazol-2-yl, 1-methyl-3-propylimidazol-2-yl, 1-butyl-3-methylimidazol-2-yl, 1-methyl-3-pentylimidazol-2-yl, 1,3-diethylimidazol-2-yl, 1-ethyl-3-propylimidazol-2-yl, 1-ethyl-3-butylimidazol-2-yl, 1-ethyl-3-pentylimidazol-2-yl, 1,3-diphenyl-1H-1,2,4-triazol-4-onth-3-yl), ... propylimidazolium-2-ylene, 1-propyl-3-butylimidazolium-2-ylene, 1-propyl-3-pentylimidazolium-2-ylene, 1,3-dibutylimidazolium-2-ylene, 1-butyl-3-pentylimidazolium-2-ylene, 1,3-dipentylimidazolium-2-ylene, 1,3-diisopropylimidazolium-2-ylene, 1,3-bis(2,4,6-trimethylphenyl)-imidazolium-2-ylene, 1-methyl-3-phenylimidazolium-2-ylene, 1-ethyl-3-phenylimidazolium-2-ylene, 1-propyl-3-phenylimidazolium-2-ylene, 1-butyl-3-phenylimidazolium-2-ylene, 1-pentyl-3-phenylimidazolium-2-ylene - Isomeric groups, including 1,3-diphenylimidazolium-2-ylmeric groups, 1,3-dimethylimidazolium-2-ylmeric groups, 1-methyl-3-ethylimidazolium-2-ylmeric groups, 1-methyl-3-propylimidazolium-2-ylmeric groups, 1-methyl-3-butylimidazolium-2-ylmeric groups, 1-methyl-3-pentylimidazolium-2-ylmeric groups, 1,3-diethylimidazolium-2-ylmeric groups, 1-ethyl-3-propylimidazolium-2-ylmeric groups, 1-ethyl-3-butylimidazolium-2-ylmeric groups, 1,3-dipropylimidazolium-2-ylmeric groups, 1-propyl-3-butylimidazolium-2-ylmeric groups, 1-propyl -3-pentylimidazoline-2-ylene, 1,3-dibutylimidazoline-2-ylene, 1-butyl-3-pentylimidazoline-2-ylene, 1,3-dipentylimidazoline-2-ylene, 1,3-diisopropylimidazoline-2-ylene, 1,3-di(2,4,6-trimethylphenyl)-imidazoline-2-ylene; 1-methyl-3-phenylimidazoline-2-ylene, 1-ethyl-3-phenylimidazoline-2-ylene, 1-propyl-3-phenylimidazoline-2-ylene, 1-butyl-3-phenylimidazoline-2-ylene, 1-pentyl-3-phenylimidazoline-2-ylene, 1,3-diphenylimidazoline-2-ylene;1,3-Dimethylbenzimidazole-2-ylene, 1-Methyl-3-ethylbenzimidazole-2-ylene, 1-Methyl-3-propylbenzimidazole-2-ylene, 1-Methyl-3-butylbenzimidazole-2-ylene, 1-Methyl-3-pentylbenzimidazole-2-ylene, 1,3-Diethylbenzimidazole-2-ylene, 1-Ethyl-3-propylbenzimidazole-2-ylene, 1-Ethyl-3-butylbenzimidazole-2-ylene, 1-Ethyl-3-pentylbenzimidazole-2-ylene, 1,3-Dipropylbenzimidazole-2-ylene, 1-Propyl-3-butylbenzimidazole-2-ylene, 1-Propyl-3-pentylbenzimidazole -2-ylenetrile, 1,3-dibutylbenzimidazole-2-ylenetrile, 1-butyl-3-pentylbenzimidazole-2-ylenetrile, 1,3-dipentylbenzimidazole-2-ylenetrile, 1,3-diisopropylbenzimidazole-2-ylenetrile, 1,3-bis(2,4,6-trimethylphenyl)benzimidazole-2-ylenetrile, 1-methyl-3-phenylbenzimidazole-2-ylenetrile, 1-ethyl-3-phenylbenzimidazole-2-ylenetrile, 1-propyl-3-phenylbenzimidazole-2-ylenetrile, 1-butyl-3-phenylbenzimidazole-2-ylenetrile, 1-pentyl-3-phenylbenzimidazole-2-ylenetrile, and 1,3-diphenylbenzimidazole-2-ylenetrile.

[0095] In equation (I), Pws is, for example, the general formula PR 1 R 2 R 3 Tertiary phosphine, selected from: P(CH2OH)3[tris(hydroxymethyl)phosphine]; Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the ortho position ( o tppms, o tppds, o tppts); Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the meta position ( m tppms, m tppds, m tppts); and Li, Na, K or Cs salts of triphenylphosphine monosulfonated at the para position (tppts); p (tppms); or cyclic tertiary phosphine, preferably 1,3,5-triaza-7-phosphaadamantane (pta).

[0096] In equation (I), Pws is, for example, the general formula R 4 2P-bridge-PR 5 2 phosphine, of which PR 4 2 and PR 52 is independently selected from: P(CH2OH)2 (bis(hydroxymethyl)phosphin); PPh2 (diphenylphosphin); Li, Na, K or Cs salts of diphenylphosphin monosulfonated or disulfonated at the ortho position; Li, Na, K or Cs salts of diphenylphosphin monosulfonated or disulfonated at the meta position; Li, Na, K or Cs salts of diphenylphosphin monosulfonated or disulfonated at the para position; or covalently bridged cyclic tertiary phosphin, preferably 1,3,5-triaza-7-phosphaadamantane (pta).

[0097] In another embodiment of the catalyst of formula (I), M is manganese, iron, cobalt, nickel, or copper; NHC is 1-ethyl-3-methylimidazolium-2-ylene; Pws is a Li, Na, K, or Cs salt of triphenylphosphine monosulfonated, disulfonated, or trisulfonated at the meta position. m tppms, m tppds, m tppts); L¹ is H - F - Cl - ,Br - I - or CH3CO2 - (Acetate).

[0098] In one embodiment of the invention, the catalyst used is a non-separated (in-situ generated) catalyst produced using the following methods: A water-soluble salt of metal M and at least 1 equimolar amount of NHC precursor and / or Pws ligand relative to the metal ion. in, M, NHC, and Pws are defined as above.

[0099] In embodiments of the present invention, the NHC precursor used to generate the non-separated catalyst is selected from: (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron, and 1-R 1 -3-R 2 -Imidazolium, 1-R 1 -3-R 2 -imidazolinium and 1-R 1 -3-R 2 - A salt of benzimidazolium, wherein R 1 and R 2 Each is independently a straight-chain or branched alkyl, benzyl, or phenyl group having 1 to 6 carbon atoms, which is either unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms.

[0100] In another embodiment, the NHC precursor is selected from: 1-ethyl-3-methylimidazolium chloride (emimCl), 1-butyl-3-methylimidazolium chloride (bmimCl), 1-hexyl-3-methylimidazolium chloride (hexmimCl), 1-benzyl-3-methylimidazolium chloride (BnmimCl), 1-ethyl-3-methylimidazolium acetate (emimAc), 1-butyl-3-methylimidazolium acetate (bmimAc), 1-hexyl-3-methylimidazolium acetate (hexmimAc), and 1-benzyl-3-methylimidazolium acetate (BnmimAc), or (1,4-diphenyl-1H-1,2,4-triazol-4-on-3-yl)(phenyl)nitron.

[0101] In another embodiment of the invention, the NHC precursor used to generate the in-situ generated catalyst is selected from the group consisting of: 1-ethyl-3-methylimidazolium chloride (emimCl), 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride (bmimCl), 1-hexyl-3-methylimidazolium chloride (hexmimCl), 1-benzyl-3-methylimidazolium chloride (BnmimCl), and (1,4-diphenyl-1H-1,2,4-triazol-4-on-3-yl)(phenyl)nitron.

[0102] In another embodiment of the invention, the NHC precursor used to prepare the non-separated catalyst is 1-ethyl-3-methylimidazolium chloride (emimCl), 1-butyl-3-methylimidazolium chloride (bmimCl), 1-hexyl-3-methylimidazolium chloride (hexmimCl), 1-benzyl-3-methylimidazolium chloride (BnmimCl), 1-ethyl-3-methylimidazolium acetate (emimAc), 1 1-Butyl-3-methylimidazolium acetate (bmimAc), 1-hexyl-3-methylimidazolium acetate (hexmimAc), and 1-benzyl-3-methylimidazolium acetate (BnmimAc), (1,4-diphenyl-1H-1,2,4-triazol-4-onth-3-yl)(phenyl)nitron; Pws is a Li, Na, K, or Cs salt of triphenylphosphine monosulfonated, disulfonated, or trisulfonated at the meta position. m tppms, m tppds, m tppts), or 1,3,5-triaza-7-phosphaadamantane (pta).

[0103] The water-soluble salt of metal M used to prepare the in-situ catalyst is a water-soluble salt of the metal defined above. It will be apparent to those skilled in the art that the formation of the complex is generally little affected by the starting salt. Furthermore, the presence of strong σ-donor ligands (NHC and / or Pws) is found to be a key factor in this invention; therefore, there are no particular restrictions on the type of anion in the water-soluble salt, provided that the salt is water-soluble. The latter is necessary because the in-situ catalyst is formed and used in an aqueous reaction medium. Selecting a suitable metal salt is not difficult for those skilled in the art. Typical salts are halides, nitrates, sulfates, acetates, etc., of metal M as defined above. Chlorides or acetates are most commonly used due to their ease of availability.

[0104] Typical metal salts used include: NiCl2×6H2O, CuCl, CuCl2×H2O, FeCl2×4H2O, FeCl3×nH2O, MnCl2×H2O, CoCl2, LaCl3×7H2O, TiOSO4×xH2O×yH2SO4, NH4VO3, (NH4)2MoO4×4H2O, YCl3×6H2O, CrCl3×6H2O, SnCl2×2H2O, cobalt diacetate, copper diacetate, manganese diacetate, NiCO3, etc.

[0105] For the preparation of non-separated catalysts, at least 1 equimolar amount of NHC precursor and / or Pws ligand is used relative to each M metal ion. Typically, no more than six ligands are introduced into the complex, but to promote the complexation reaction, a relatively large excess of ligands, up to 0-10 equimolar amounts of NHC precursor and 0-10 equimolar amounts of Pws ligand, can be used. However, 0-6 equimolar amounts of NHC precursor and 0-6 equimolar amounts of Pws ligand are generally used. In most cases, the NHC precursor and / or Pws ligand are added in a total maximum of 6 equimolar amounts.

[0106] In embodiments of the present invention, the non-separated catalyst is prepared using 0-2 equimolar amounts of NHC precursor and / or 0-2 equimolar amounts of Pws ligand relative to metal ion M, provided that the NHC precursor and Pws ligand are present in an amount of 1-4 equimolar amounts relative to the total amount of metal ion.

[0107] It will be apparent to those skilled in the art that, in the case of non-separated catalysts, the complexes or catalytic units are formed in the reaction mixture from the metal salts and ligands used, the precise molecular formula / structure of which may or may not be known. However, based on the starting materials used, general knowledge, and proven catalytic activity, it can be assumed that the in-situ formed complexes correspond to general formulas (I), (II), or (III).

[0108] The isolated or non-isolated catalysts used according to the invention are optionally used with an excess of ligands, typically an excess of water-soluble phosphine ligands.

[0109] We note that, in the case of a separate catalyst, the catalyst defined by formula (I), (II), or (III) refers to the metal complex compound added to the reaction mixture. It will be apparent to those skilled in the art that the precise molecular formula / structure of the catalytic unit (active substance) formed in the aqueous medium may differ depending on the composition of the reaction mixture (e.g., formation of solvated complexes, conversion of polynuclear starting compounds to mononuclear metal complexes, ligand exchange with excess water-soluble phosphine (Pws), L¹ (ionic), and / or L² (neutral) ligands). Therefore, the given catalyst molecular formula can be considered as a precursor to the actual catalytic unit (active substance).

[0110] It should also be noted that certain metals, particularly iron and cobalt, are known to form polynuclear complexes. Polynuclear complexes comprising a metal (particularly iron or cobalt) as defined in the catalysts of this invention and at least one strong σ-donor ligand selected from N-heterocyclic carbene ligands and water-soluble phosphine ligands also fall within the scope of this invention. These catalysts are defined by general formulas (II) and (III) and are considered to be closely analogous to the catalysts characterized by general formula (I).

[0111] It is obvious to those skilled in the art that if Pws is a polydentate ligand, then the ligand can coordinate with a metal atom through one or more P atoms.

[0112] We also note that, in the case of the negative ion (L¹) in the formula of the catalyst, it is not always clear whether the ion is indeed coordinated in the complex as a ligand or should be considered more as an antiion. However, in the context of this invention, the anion in the formula in the embodiments is considered as an L¹ ligand.

[0113] The present invention also relates to a process for releasing hydrogen, wherein the process includes, in an aqueous reaction system, decomposing formate in the presence of a catalyst as defined above, to produce CO-free gas. x The byproduct hydrogen gas, the formate is preferably sodium formate (HCO2Na), lithium formate (HCO2Li), cesium formate (HCO2Cs) and / or potassium formate (HCO2K).

[0114] The hydrogen release process is carried out in an oxygen-free atmosphere at an elevated temperature and at a pH greater than 8, wherein the elevated temperature is preferably 60-100°C, more preferably 60-80°C, and the pH is preferably pH=8.3±0.2.

[0115] The present invention also relates to a process for storing hydrogen, wherein the process includes, in an aqueous reaction system, in the presence of a catalyst as defined above, reacting bicarbonate (HCO3) - The bicarbonate is hydrogenated to produce a formate, wherein the bicarbonate is preferably sodium bicarbonate (NaHCO3), lithium bicarbonate (LiHCO3), cesium bicarbonate (CsHCO3) and / or potassium bicarbonate (KHCO3), and the formate is preferably sodium formate (HCO2Na), lithium formate (HCO2Li), cesium formate (HCO2Cs) and / or potassium formate (HCO2K).

[0116] The hydrogen storage process is carried out in an oxygen-free atmosphere at an elevated temperature and an H2 pressure of 1-1200 bar, wherein the elevated temperature is preferably 60-100°C, more preferably 80°C, and the H2 pressure is preferably 10-100 bar, more preferably 30-40 bar, and even more preferably 30 bar or 40 bar.

[0117] If the catalytic hydrogenation of bicarbonate to formate according to the invention and the catalytic decomposition of formate to bicarbonate according to the invention are combined in such a way that the steps mentioned are carried out in the same reaction system in an aqueous medium in the presence of a water-soluble catalyst, i.e., the reactants and reaction products are formed in a reversible reaction cycle, a hydrogen storage system, preferably a hydrogen accumulator, can be formed.

[0118] Therefore, the present invention also relates to a process for releasing and storing hydrogen, the process comprising the following steps: i) In an aqueous reaction system, in the presence of the catalyst as defined above, formate is decomposed to produce CO-free products. x The byproduct hydrogen gas (H2), wherein the formate is preferably sodium formate (HCO2Na), lithium formate (HCO2Li), cesium formate (HCO2Cs), and / or potassium formate (HCO2K); and ii) In an aqueous reaction system, in the presence of the catalyst used in step i), the bicarbonate (HCO3) produced in step i) is reacted... - The bicarbonate is hydrogenated to produce formate, wherein the bicarbonate is preferably sodium bicarbonate (NaHCO3), lithium bicarbonate (LiHCO3), cesium bicarbonate (CsHCO3), and potassium bicarbonate (KHCO3), and the formate is preferably sodium formate (HCO2Na), lithium formate (HCO2Li), cesium formate (HCO2Cs), and / or potassium formate (HCO2K). The decomposition of the formate is carried out in an anaerobic atmosphere at an elevated temperature and at a pH greater than 8, wherein the elevated temperature is preferably 60-100°C, more preferably 60-80°C, and the pH is preferably pH=8.3±0.2. Furthermore, the hydrogenation step of the bicarbonate is carried out in an oxygen-free atmosphere at an elevated temperature and an H2 pressure of 1-1200 bar, wherein the elevated temperature is preferably 60-100°C, more preferably 80°C, and the H2 pressure is preferably 10-100 bar, more preferably 30-40 bar, more preferably 30 bar or 40 bar. Furthermore, the reactants and products are formed in a reversible reaction cycle of the reaction system using the formate decomposition step and the bicarbonate hydrogenation step, and this reaction cycle is optionally repeated.

[0119] Therefore, according to embodiments of the present invention, the process for storing hydrogen and the process for releasing hydrogen are carried out in a single reaction system, namely a hydrogen storage system.

[0120] Hydrogen storage systems can be used in such a manner that the catalytic hydrogenation of bicarbonate takes place in a hydrogenation reactor near a renewable energy production facility to store energy generated beyond immediate demand (energy not immediately used). The formate solution is then transported and the hydrogen is released in another facility (for use, for example, directly in a chemical reaction, or for generating electricity, for example, in a fuel cell). The remaining bicarbonate solution can then be returned to the hydrogenation reactor for re-hydrogenation. In this case, although the hydrogen storage system is chemically considered the same system, it is not called a hydrogen accumulator.

[0121] According to a more preferred embodiment, the reaction is carried out in the same reaction system and in the same device, in which case the hydrogen storage system is a hydrogen accumulator.

[0122] The present invention also relates to the use of the hydrogen storage system according to the invention for storing and releasing (if needed) the hydrogen required for the operation of fuel cells (or other devices that require H2).

[0123] The method for preparing the metal complexes used as catalysts as described in this specification is detailed below. The compounds used as starting materials are commercially available.

[0124] Preparation method A A-1. Preparation of free carbene Under inert conditions, 1.09 equivalents of t-BuOK (2.7305 mmol) were added to a solution of the desired NHC chloride (most commonly emim, bmim, etc.) (2.5051 mmol) in 8 mL of THF (after stirring at room temperature for 15 minutes), followed by an additional 20 minutes of stirring. The pale yellow mixture was then passed through a Hyflo Super-Cel filter. ® Filtration with filter aids.

[0125] A-2. Metallic Carbene ([M(NHC)]) n (L1 ) q (L 2 ) r Preparation of coordination compounds Add an appropriate amount of metal salt (e.g., M-chloride [e.g.]) NiCl 2 ×6H 2 O, CuCl, CuCl 2 ×H 2 O, FeCl 2 × 4H 2 O, FeCl 3 ×nH 2 O, MnCl 2 ×H 2 O, CoCl 2 LaCl 3 ×7H 2 O, NH 4 VO 3 、(NH 4 ) 2 MoO 4 ×4H 2 O, YCl 3 ×6H 2 O、 CrCl 3 ×6H 2 O, SnCl 2 ×2H 2 O、TiOSO 4 ×xH 2 O×yH 2 SO A solution of [4](2.5051 mmol) in 5 mL of THF was stirred at 50 °C for 40 min. Simultaneously, a free carbene solution was prepared as described in A-1. (The metal salt and carbene were equimolar.) Then, the yellow solution of the free carbene was added to the solution of the metal salt under inert conditions, and the reaction mixture was refluxed for 4 h. After 4 h, the mixture was cooled. The desired product ([M(NHC)) was then... n (L 1 ) q (L 2 ) r The precipitate is removed from the solution by pipetting, and the resulting material is then washed with ether and dried under vacuum. If the desired product does not precipitate from the reaction mixture, the solution is evaporated, washed with ether, and dried under vacuum.

[0126] A-3. Metal-carbene-phosphine ([M(NHC)]) n (Pws) p (L 1 ) q (L 2 ) r Synthesis of coordination compounds Under inert conditions, the M-carbene complex (50 mg) obtained at point A-2 was dissolved in 8 mL of methanol, and then an appropriate amount (1 equivalent) of phosphine compound (Pws: m tppms, m (tppts). The mixture was then stirred at 50°C for 4 hours. After the reaction time was complete, the solution was cooled and then evaporated. The resulting catalyst was washed with diethyl ether and dried under vacuum.

[0127] It should be noted that step A-2 above is primarily used to introduce carbene ligands (NHC), and step A-3 is used to introduce phosphine ligands (Pws). However, during the reaction, L¹ ionic ligands and L² neutral ligands from components present in the reaction mixture can also be introduced into the complex (e.g., the anion of the weighed salt or H₂O molecules from the water of crystallization in the salt; furthermore, the coordination solvent itself can remain in the coordination layer as an anionic or neutral ligand). This consideration is applied in a similar manner to the following preparation routes D and E.

[0128] Preparation method B Preparation of B-1. [Mn(CO)4Br(NHC)] A solution of [Mn(CO)₅Br] (2.5051 mmol) in 5 mL of THF was stirred at 50 °C for 40 min. Simultaneously, a free carbene solution was prepared as described in A-1 (metal salt and carbene were 1 equivalence). Then, the yellow solution of free carbene was added to the [Mn(CO)₅Br] solution under inert conditions, and the reaction mixture was refluxed for 4 h. After 4 h, the mixture was cooled. The solution was evaporated, washed with diethyl ether, and dried under vacuum.

[0129] B-2.[Mn(CO)2-3Br(NHC)(Pws) 1-2 Preparation of coordination compounds The [Mn(CO)4Br(NHC)] complex (1.0281 mmol) prepared according to B-1 was dissolved in 15 mL of THF, and an appropriate amount of 1 or 2 equivalents of phosphine (Pws: ) was added under a nitrogen atmosphere. m (tppms, pta). Then stir at 50°C for 4 hours. If the desired product precipitates from the solution, remove the solution phase with a pipette, wash the solid residue with diethyl ether, and then dry the resulting material under vacuum. If the product does not precipitate from the reaction mixture, evaporate the solution, wash with diethyl ether, and then dry under vacuum.

[0130] Preparation method C C-1.[Fe3(CO) 11 Preparation of (NHC) Add an appropriate amount of [Fe3(CO)] 12 A solution of 2.5051 mmol of carbene in 5 mL of THF was stirred at 50 °C for 40 minutes. Simultaneously, a solution of free carbene was prepared as described in A-1. Then, the yellow solution of free carbene was added in equimolar amounts to [Fe3(CO)] under inert conditions. 12 The mixture was placed in a solution and the reaction mixture was refluxed for 4 hours. After 4 hours, the mixture was cooled. The solution was evaporated, washed with ether, and dried under vacuum.

[0131] C-2.[Fe3(CO) 10 Preparation of [(NHC)(Pws)], [Fe3(CO)9(NHC)(Pws)2] and [Fe3(CO)8(NHC)(Pws)3] [Fe3(CO)] prepared according to C-1 11 The (NHC)] complex (0.6629 mmol) was dissolved in 15 mL of THF, and an appropriate amount (1-3 equivalents) of phosphine (Pws:) was added under a nitrogen atmosphere. m (tppms, pta). Then stir at 50°C for 4 hours. Finally, cool the solution; the solid product precipitates during cooling. Remove the solution phase with a pipette, wash the resulting material with diethyl ether, and then dry under vacuum.

[0132] Preparation method D Preparation of D-1.Ag-NHC At room temperature, a solution of 1.30 mmol NHC chloride (NHC: emim, bmim, Bnmim, hexmim) in 10 mL of dichloromethane was added to a suspension of 0.65 mmol Ag₂O in 20 mL of dichloromethane, and the reaction mixture was stirred at reflux for 3 hours. Almost all of the Ag₂O reacted, and the black suspension became a clear solution. This solution was then passed through a Hyflo Super-Cel filter. ® Filtration with a filter aid was used to remove unreacted Ag₂O. The solvent was removed under vacuum, and the resulting material was used to prepare the corresponding M-NHC complexes.

[0133] D-2. Metallic Carbene ([M(NHC)]) n (L 1 ) q (L 2 ) r Preparation of coordination compounds A solution of a metal salt (0.85 mmol) in 0.5 mL of 2-methoxyethanol was added in small portions to a solution of Ag-NHC (0.49 mmol) prepared according to D-1 in 20 mL of dichloromethane. The resulting reaction mixture was then stirred at reflux temperature for 4 hours. After cooling the reaction mixture, the solution was passed through a Hyflo Super-Cel... ® Filter with a filter aid to remove AgCl. Remove the solvent under vacuum. Wash the remaining viscous substance with diethyl ether until a solid material is obtained. Finally, the obtained [M(NHC)] n (L 1 ) q (L 2 ) r Complexes can be used directly in catalytic reactions.

[0134] D-3. Metal-carbene-phosphine ([M(NHC)]) n (Pws) p (L 1 ) q (L 2 ) r Synthesis of coordination compounds Water-soluble phosphine (Pws: equivalent to metal) m tppms, m tppts, pta) are added to various [M(NHC)] compounds prepared according to D-2. n (L 1 ) q (L 2 ) r The complex was dissolved in methanol, and the resulting solution was stirred at 50°C for 4 hours. After the reaction time, it was passed through a Hyflo Super-Cel reactor. ® Filter with a filter aid. Remove the solvent under vacuum. Then, wash the residue with ether until a solid material is obtained, and finally dry it under vacuum.

[0135] Preparation method E E-1.[M(Nitron)(L 1 ) q (L 2 ) r Preparation of ] At room temperature, 0.64 mmol nitron dissolved in 10 mL acetonitrile was added dropwise to 0.64 mmol of a metal salt [e.g., nitron]. NiCl 2 ×6H 2 O, CuCl, CuCl 2 ×H 2 O, FeCl 2 ×4H 2 O, FeCl 3 ×nH 2 O, MnCl 2 ×H 2 O, CoCl 2 LaCl 3 × 7H 2 O、TiOSO 4 ×xH 2 O×yH 2 SO 4] In a solution of 10 mL acetonitrile. The mixture was then stirred at reflux temperature for 6 hours, and the solvent was removed under vacuum. The resulting material was washed with diethyl ether and dried under vacuum. The solid material thus obtained ([M(Nitron)(L)) 1 ) q (L 2 ) r It can be used directly in catalytic reactions.

[0136] E-2. Metal-nitron-phosphine ([M(Nitron)(Pws)) p (L 1 ) q (L 2 ) r Synthesis of coordination compounds Water-soluble phosphine (Pws: equivalent to metal) m tppms, m tppts, pta) were added to various [M(Nitron)(L) compounds prepared according to E-1. 1 ) q (L 2 ) r The complex was dissolved in methanol, and the resulting solution was stirred at 50°C for 4 hours. After the reaction time, it was passed through a Hyflo Super-Cel reactor. ® Filter with a filter aid. Remove the solvent under vacuum. Then, wash the residue with ether until a solid material is obtained, and finally dry it under vacuum.

[0137] The application results of the novel catalysts prepared by different methods are summarized in Table 3-10. In each case, the preparation method of the complex and its activity are specified separately.

[0138] Examples of the implementation schemes are described below, wherein the catalyst generated or prepared and isolated in AE by the above method exhibits catalytic activity in the dehydrogenation and / or hydrogenation process of a given reaction system.

[0139] Example Description of a general dehydrogenation reaction system: Reaction conditions: [formate] / [M] = 5-200; T = 60-80℃; reaction time = 1-2 hours; V = 2-5 mL; the amount of formate converted is determined by HPLC, and the conversion rate values ​​in all cases refer to the conversion (consumption) of the initial formate.

[0140] Dehydrogenation is always carried out in an oxygen-free atmosphere (in the presence of nitrogen). An oxygen-free atmosphere may also be provided, for example, with argon. Furthermore, dehydrogenation is always carried out at pH = 8.3 ± 0.2 to ensure that the loss of stored material is avoided, including the decomposition of bicarbonate and the formation of carbon dioxide, as previously described.

[0141] Example 1: Study on the role of cobalt complex catalysts in dehydrogenation i. Metal salt: cobalt diacetate; NHC precursor: 1-ethyl-3-methylimidazolium chloride; Pws: m tppts-Na3 At room temperature, mix the following substances in 3 mL of MeOH: 10 mg cobalt diacetate × 4H₂O (0.04 mmol), 12 mg emim (HCl) (0.082 mmol), and 8.5 mg Na₂CO₃ (0.081 mmol). Stir the resulting solution for 1 hour, then add 62 mg of... m tppts-Na3 (2 equivalents). A pale purple, powdery solution was obtained during 1 hour of stirring. The solvent was removed under vacuum, and 2.0 mL of water and 100 mg of potassium formate (1.2 mmol) were added to the residue. Dehydrogenation was carried out at 60 °C for 1 hour. The experiment was performed twice, and the conversion rate was 10-11% as determined by HPLC.

[0142] ii. Metal salt: cobalt diacetate; NHC precursor: 1-ethyl-3-methylimidazolium chloride At room temperature, the following substances were mixed in 2 mL of MeOH: 25 mg cobalt diacetate × 4H₂O (0.1 mmol), 30 mg emim (HCl) (0.2 mmol), and 21 mg Na₂CO₃ (0.2 mmol). The resulting solution was stirred for 1 hour to obtain a bluish-purple solution. The solvent was removed under vacuum, and 2.0 mL of water and 96 mg of potassium formate (1.14 mmol) were added to the residue. Dehydrogenation was carried out at 60 °C for 1 hour. This experiment was performed twice, and the conversion rate was determined by HPLC to be 11–13%.

[0143] iii. Metal salt: cobalt diacetate; NHC precursor: 1-ethyl-3-methylimidazolium acetate; Pws: m tppts-Na3 At room temperature, mix the following substances in 2 mL of MeOH: 30 mg cobalt diacetate × 4H₂O (0.12 mmol), 40 mg (0.24 mmol) emim acetate, and 140 mg m 0.23 mmol of Na₂CO₃ was added to the resulting pink solution. The solution was stirred for 72 hours to obtain a pink solution containing a pale white solid. After filtration, the solvent was removed under vacuum, and 2.0 mL of water and 112 mg of potassium formate (1.33 mmol) were added to the residue. Dehydrogenation was carried out at 60 °C for 1 hour. This experiment was performed 5 times, and the conversion rate was determined by HPLC to be 15-22%.

[0144] iv. Metal salt: cobalt diacetate; NHC precursor: 1-ethyl-3-methylimidazolium acetate At room temperature, the following substances were mixed in 5 mL of MeOH: 20 mg cobalt diacetate × 4H₂O (0.08 mmol) and 27 mg emim acetate (0.16 mmol). The resulting deep pink solution was stirred for 23 hours, and the solvent was removed under vacuum. 2.0 mL of water and 104 mg potassium formate (1.24 mmol) were added to the resulting purple viscous substance (which had dissolved). Dehydrogenation was carried out at 60 °C for 1 hour. This experiment was performed four times, and the conversion rate was determined by HPLC to be 6-11%.

[0145] v. Systematic research (Table 3): Commonly used reaction conditions The mass of the Co-complex was 10 mg, the potassium formate was 25 mg, the water was 2.0 mL, the reaction time was 2 hours, the temperature was 80 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0146] Table 3

[0147] Example 2: Study on the role of copper complex catalysts in dehydrogenation i. Metal salt: [CuCl]; NHC precursor: 1-ethyl-3-methylimidazolium acetate; Pws: m tppts-Na3 At room temperature, the following substances were mixed in 2 mL of MeOH: 10 mg [CuCl] (0.1 mmol) and 14 mg emim acetate (0.08 mmol). 22 mg Na₂CO₃ (0.21 mmol) was added to the resulting yellowish-green solution, and the mixture was stirred for 1 hour to obtain a yellowish-green solution and a yellowish-green solid. 62 mg of [CuCl] was then added to this solution. m0.1 mmol of tppts-Na3 was added and stirred for 0.5 hours. The solvent was then removed under vacuum, and 2.0 mL of water and 52 mg of potassium formate (0.62 mmol) were added to the residue. Dehydrogenation was carried out at 60 °C for 1 hour. This experiment was performed once, and the conversion rate was 8% as determined by HPLC.

[0148] ii. Metal salt: Copper diacetate; NHC precursor: 1-ethyl-3-methylimidazolium chloride; Pws: m tppts-Na3 Mix the following substances in 2 mL of water: 10 mg copper diacetate (0.055 mmol) and 90 mg... m 0.144 mmol of Na3 was dissolved in tppts to obtain a pale green solution. NaBH4 solution (5 equivalents) was slowly added dropwise to the resulting solution while cooling with ice. The solution was stirred for 1 hour to obtain a pinkish-red solution, to which 20 mg of emim (HCl) (0.136 mmol) was added. After stirring for 0.5 hours, 100 mg of potassium formate (1.2 mmol) was added. Dehydrogenation was carried out at 60 °C for 1 hour. This experiment was performed twice, and the conversion rate was determined by HPLC to be 3-5%.

[0149] iii. Metal salt: Copper diacetate; Pws: m tppts-Na3 Mix the following substances in 2 mL of water: 10 mg copper diacetate (0.055 mmol) and 90 mg... m 0.144 mmol of tppts-Na3 was used to obtain a pale green solution, to which 100 mg of potassium formate (1.2 mmol) was added. Dehydrogenation was carried out at 60 °C for 1 hour. The experiment was performed twice, and the conversion rate was 20% as determined by HPLC.

[0150] iv. Systematic studies (Table 4): Commonly used reaction conditions The mass of Cu(I) complex was 10 mg, potassium formate was 25 mg, water was 2.0 mL, the reaction time was 2 hours, the temperature was 60 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0151] Table 4

[0152] v. Systematic research (Table 5): Commonly used reaction conditionsThe mass of Cu(II) complex was 10 mg, potassium formate was 25 mg, water was 2.0 mL, the reaction time was 2 hours, the temperature was 60 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0153] Table 5

[0154] Example 3: Study on the role of nickel complex catalysts in dehydrogenation i. Systematic studies (Table 6): Commonly used reaction conditions The mass of the Ni(II) complex was 10 mg, the potassium formate was 25 mg, the water was 2.0 mL, the reaction time was 2 hours, the temperature was 60 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0155] Table 6

[0156] Example 4: Study on the role of manganese complex catalysts in dehydrogenation i. Metal salt: manganese diacetate; NHC precursor: 1-ethyl-3-methylimidazolium acetate At room temperature, the following substances were mixed in 2 mL of MeOH: 23 mg manganese diacetate (0.13 mmol) and 46 mg emim acetate (0.27 mmol), yielding a colorless solution. 28 mg Na₂CO₃ (0.26 mmol) was then added to this solution. The solution was stirred for 20 hours, yielding a pale yellow / brown solution and a pale brown solid. After filtration, the solvent was removed under vacuum. 2.0 mL of water and 121 mg potassium formate (1.44 mmol) were added to the residue. Dehydrogenation was carried out at 60 °C for 1 hour. This experiment was performed twice, and the conversion rate, as determined by HPLC, was 14–15%.

[0157] ii. Metal salt: Manganese diacetate; Pws: m tppts-Na3 Mix the following substances in 7 mL of water: 17 mg manganese diacetate (0.1 mmol) and 380 mg manganese diacetate (0.1 mmol). m 0.6 mmol of Na₂BH₄ solution was added dropwise to this solution while cooling with ice. The resulting solution was stirred for 2 hours (yellow solution). 115 mg of potassium formate (1.37 mmol) was added to the resulting solution. Dehydrogenation was carried out at 60 °C for 1 hour. The conversion rate was 55% as determined by HPLC.

[0158] iii. Metal salt: manganese diacetate; NHC precursor: 1-ethyl-3-methylimidazolium chloride; Pws: m tppts-Na3 Mix the following substances in 7 mL of water: 17 mg manganese diacetate (0.1 mmol) and 380 mg manganese diacetate (0.1 mmol). m 0.6 mmol of Na₂BH₄ solution was added dropwise to this solution while cooling with ice. The resulting solution was stirred for 2 hours (yellow solution). 132 mg of emim (HCl) (0.9 mmol) was added to the resulting solution (the solution color did not change). 115 mg of potassium formate (1.37 mmol) was added to this solution. Dehydrogenation was carried out at 60 °C for 1 hour. The conversion rate was 25% as determined by HPLC.

[0159] iv. Metal salt: manganese diacetate; NHC precursor: 1-ethyl-3-methylimidazolium acetate; Pws: m tppts-Na3 Mix the following substances in 4 mL of MeOH: 36 mg manganese diacetate (0.21 mmol), 70 mg emim acetate (0.41 mmol), and 320 mg... m 0.51 mmol of tppts-Na3 was reacted to obtain a yellowish solution. 44 mg of Na2CO3 (0.42 mmol) was then added to this solution. The solution was stirred at room temperature for 20 hours, yielding a pale yellow solution and an off-white solid. After filtration, the solvent was removed under vacuum, resulting in a brown, viscous substance. 2.0 mL of water was added to this substance (resulting in a clear, yellowish solution) and 108 mg of potassium formate (1.29 mmol). Dehydrogenation was carried out at 60 °C for 1 hour. The conversion rate, as determined by HPLC, was 10%.

[0160] v. Metal complex: [MnCl2( m tppms-Na)2] 15 mg of the previously prepared [MnCl2( m The [tppms-Na)2] complex (0.016 mmol) was dissolved in 2 mL of water to obtain a colorless, clear solution. 27 mg of potassium formate (0.32 mmol) was added to this solution. Dehydrogenation was carried out at 60 °C for 2 hours. This experiment was performed twice, and the conversion rate, as determined by HPLC, was 2–3%.

[0161] vi. Systematic research (Table 7): Commonly used reaction conditionsThe mass of the Mn(II) complex was 10 mg, the potassium formate was 25 mg, the water was 2.0 mL, the reaction time was 2 hours, the temperature was 60 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0162] Table 7

[0163] vii. Systematic research (Table 8): Commonly used reaction conditions The mass of the Mn(I) complex was 10 mg, the potassium formate was 25 mg, the water was 2.0 mL, the reaction time was 2 hours, the temperature was 80 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0164] Table 8

[0165] Example 5: Study on the role of iron complex catalysts in dehydrogenation i. Systematic studies (Table 9): Commonly used reaction conditions The mass of Fe(II) complex was 10 mg, potassium formate was 25 mg, water was 2.0 mL, the reaction time was 2 hours, the temperature was 60 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0166] Table 9

[0167] ii. Systematic studies (Table 10): Common reaction conditions The mass of Fe(0) complex was 10 mg, potassium formate was 25 mg, water was 2.0 mL, the reaction time was 2 hours, the temperature was 60 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0168] Table 10

[0169] Example 6: Study on the role of lanthanum complex catalysts in dehydrogenation i. Systematic studies (Table 11): Common reaction conditions The mass of the La(III) complex was 10 mg, the potassium formate was 25 mg, the water was 2.0 mL, the reaction time was 2 hours, the temperature was 60 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0170] Table 11

[0171] Example 7: Study on the role of titanium complex catalysts in dehydrogenation i. Systematic studies (Table 12): Common reaction conditions The mass of Ti(IV) complex was 10 mg, potassium formate was 25 mg, water was 2.0 mL, the reaction time was 2 hours, the temperature was 80 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0172] Table 12

[0173] Example 8: Study on the role of tin complex catalysts in dehydrogenation.

[0174] i. Systematic studies (Table 13): Common reaction conditions The mass of Sn(II) complex was 10 mg, potassium formate was 25 mg, water was 2.0 mL, the reaction time was 2 hours, the temperature was 80 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0175] Table 13

[0176] Example 9: Study on the role of vanadium complex catalysts in dehydrogenation.

[0177] i. Systematic studies (Table 14): Common reaction conditions The mass of the V(V) complex was 10 mg, the potassium formate was 25 mg, the water was 2.0 mL, the reaction time was 2 hours, the temperature was 80 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0178] Table 14

[0179] Example 10: Study on the role of chromium complex catalysts in dehydrogenation i. Systematic studies (Table 15): Common reaction conditions The mass of the Cr(III) complex was 10 mg, the potassium formate was 25 mg, the water was 2.0 mL, the reaction time was 2 hours, the temperature was 80 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0180] Table 15

[0181] Example 11: Study on the role of yttrium complex catalysts in dehydrogenation i. Systematic studies (Table 16): Common reaction conditions The mass of the Y(III) complex was 10 mg, the potassium formate was 25 mg, the water was 2.0 mL, the reaction time was 2 hours, the temperature was 80 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0182] Table 16

[0183] Example 12: Study on molybdenum complex catalysts in dehydrogenation.

[0184] i. Systematic studies (Table 17): Common reaction conditions The mass of the Mo(VI) complex was 10 mg, the potassium formate was 25 mg, the water was 2.0 mL, the reaction time was 2 hours, the temperature was 80 °C, and all measurements were repeated 2-3 times. The average conversion achieved is shown in the table (standard deviation is ±0.5%).

[0185] Table 17

[0186] Description of a general hydrogenation reaction system: Reaction conditions: [bicarbonate] / [M] = 20-100; T = 80℃; p(H2) = 30 or 40 bar; volume of solution used V = 20 mL; the amount of formate formed in the reaction mixture was determined by HPLC and expressed as concentration (mM; for undiluted reaction mixture).

[0187] Hydrogenation was always carried out in an oxygen-free atmosphere (in the presence of nitrogen). Furthermore, hydrogenation was always carried out at pH = 8.3 ± 0.2.

[0188] Example 13: Study on the application of cobalt complex catalysts in hydrogenation i. Metal salt: cobalt diacetate; NHC precursor: 1-ethyl-3-methylimidazolium acetate; Pws: m tppts-Na3 At room temperature, mix the following substances in 2 mL of MeOH: 30 mg cobalt diacetate × 4H₂O (0.12 mmol), 40 mg emine acetate (0.24 mmol), and 140 mg cobalt diacetate × 4H₂O (0.12 mmol). m0.23 mmol of tppts-Na3 was added to the resulting pink solution. 25 mg of Na2CO3 (0.24 mmol) was added to the solution. The solution was stirred for 72 hours to obtain a pink solution containing a pale white solid. After filtration, the solvent was removed under vacuum. The evaporated Co complex, 20.0 mL of H2O, and subsequently 200 mg of potassium bicarbonate (2.0 mmol) were added to a 100 mL reactor. Hydrogenation was carried out at 80 °C and 40 bar H2 pressure. HPLC yielded 3 mM and 4 mM formate salts after 1 h and 2 h of reaction time, respectively.

[0189] ii. Metal complex: [CoCl2(1-ethyl-3-methylimidazol-2-yl)] (A); 10 mg of [CoCl2(1-ethyl-3-methylimidazol-2-yl)] was weighed and added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.56 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0190] iii. Metal complex: [CoCl2(1-butyl-3-methylimidazolium-2-ylidene)] (A); 10 mg of [CoCl2(1-butyl-3-methylimidazolium-2-yl)] was weighed and added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 0.72 mM and 1.09 mM formate salts after 2 h and 65 h of reaction time, respectively.

[0191] iv. Metal complex: [CoCl2(1-ethyl-3-methylimidazol-2-yl) () m tppms-Na)](A; Weigh out 7 mg of [CoCl2(1-ethyl-3-methylimidazol-2-yl) () m [tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.9 mM formate was obtained by HPLC after a reaction time of 2 hours.

[0192] v. Metal complex: [CoCl2(1-ethyl-3-methylimidazol-2-yl))( m tppts-Na3)](A; Weigh 20 mg of [CoCl2(1-ethyl-3-methylimidazol-2-yl) () m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 1.24 mM formate was obtained by HPLC after a reaction time of 65 hours.

[0193] vi. Metal complex: [CoCl2(1-butyl-3-methylimidazol-2-yl))( m tppts-Na3)](A; Weigh 20 mg of [CoCl2(1-butyl-3-methylimidazol-2-ylidene))( m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 0.18 mM and 0.26 mM formate after 4 h and 17 h of reaction time, respectively.

[0194] vii. Metal complex: [CoCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid) m tppts-Na3)](E) Weigh 30 mg of the previously prepared [CoCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid) m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.2252 mM formate was obtained by HPLC over 25 hours.

[0195] Example 14: Study on the application of copper complex catalysts in hydrogenation i. Metal salt: [CuCl]; Pws: m tppts-Na3 Weigh out 10 mg CuCl (0.1 mmol) and 80 mg m0.13 mmol of tppts-Na3 was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 40 bar H2 pressure. HPLC yielded 1.4 mM, 2.3 mM, and 3.4 mM formate salts after reaction times of 1 h, 2 h, and 4 h, respectively.

[0196] ii. Metal complex: [CuCl(1-ethyl-3-methylimidazol-2-ylidene)] (A); Weigh out 40 mg [CuCl(1-ethyl-3-methylimidazol-2-ylidene)] and 20 mg m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.32 mM formate was obtained by HPLC after a reaction time of 21 hours.

[0197] iii. Metal complex: [CuCl(1-ethyl-3-methylimidazol-2-yl)] (A); Pws: m tppts-Na3 Weigh out 20 mg of [CuCl(1-ethyl-3-methylimidazol-2-ylidene)] and 20 mg of... m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 2.62 mM formate was obtained by HPLC after a reaction time of 20 hours.

[0198] iv. Metal complex: [CuCl(1-ethyl-3-methylimidazol-2-yl) () m tppms-Na)](A; Weigh 10 mg of [CuCl(1-ethyl-3-methylimidazol-2-yl)]( m [tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.5 mM formate was obtained by HPLC after a reaction time of 2 hours.

[0199] v. Metal complex: [CuCl(1-ethyl-3-methylimidazol-2-yl))( m tppts-Na3)](A;Pws:m tppts-Na3 Weigh 10 mg of [CuCl(1-ethyl-3-methylimidazol-2-yl)]( m tppts-Na3)] and 10mg m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.2 mM formate was obtained by HPLC after a reaction time of 19 hours.

[0200] vi. Metal complex: [CuCl(1-butyl-3-methylimidazol-2-ylide))( m tppts-Na3)](A; Weigh 10 mg of [CuCl(1-butyl-3-methylimidazol-2-ylidene)] m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded formate salts of 0.4 mM, 1.05 mM, and 3.94 mM after reaction times of 2 h, 3 h, and 17 h, respectively.

[0201] vii. Metal complex: [CuCl(1-butyl-3-methylimidazol-2-ylidene))( m tppts-Na3)](A;Pws: m tppts-Na3 Weigh 10 mg of [CuCl(1-butyl-3-methylimidazol-2-ylidene)] m tppts-Na3)] and 10mg m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded formate salts of 0.23 mM, 0.36 mM, and 0.57 mM after reaction times of 2 h, 3 h, and 17 h, respectively.

[0202] viii. Metal complex: [CuCl2(1-ethyl-3-methylimidazol-2-yl))( m tppms-Na)](A; Weigh 20 mg of [CuCl2(1-ethyl-3-methylimidazol-2-yl)]( m[tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.34 mM formate was obtained by HPLC after a reaction time of 18 hours.

[0203] ix. Metal complex: [CuCl2(1-ethyl-3-methylimidazol-2-yl)] m tppts-Na3)](A; Weigh out 40 mg of [CuCl2(1-ethyl-3-methylimidazol-2-yl)]( m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.14 mM formate was obtained by HPLC after a reaction time of 18 hours.

[0204] x. Metal complex: [CuCl2(1-butyl-3-methylimidazol-2-ylidene)] (A); 23 mg of [CuCl2(1-butyl-3-methylimidazolium-2-yl)] was weighed and added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.26 mM formate was obtained by HPLC after a reaction time of 17 hours.

[0205] xi. Metal complex: [CuCl2(1-butyl-3-methylimidazolium-2-ylidene))( m tppms-Na)](A; Weigh out 40 mg of [CuCl2(1-butyl-3-methylimidazol-2-ylidene))( m [tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.36 mM formate was obtained by HPLC after a reaction time of 18 hours.

[0206] xii. Metal complex: [CuCl(1,4-diphenyl-1H-1,2,4-triazol-4-onth-3-yl)(phenyl)nitrogen hybrid)] (E); Pws: m tppts-Na3 Weigh 17 mg of the previously prepared [CuCl(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid)] and 19 mg m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.3855 mM formate was obtained by HPLC over 25 hours.

[0207] Example 15: Study on the application of nickel complex catalysts in hydrogenation i. Metal salt: NiCO3; NHC precursor: 1-ethyl-3-methylimidazolium chloride; Pws: m tppts-Na3 Weigh out 20 mg NiCO3 (0.168 mmol), 30 mg 1-ethyl-3-methylimidazolium-2-ylene (HCl) (0.205 mmol), and 50 mg m 0.08 mmol of tppts-Na3 was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 40 bar H2 pressure. HPLC yielded 1 mM and 2.3 mM formate salts after 2 h and 4 h of reaction time, respectively.

[0208] ii. Metal complex: [NiCl2(1-ethyl-3-methylimidazol-2-yl) () m tppts-Na3)](A; Weigh 10 mg of the previously prepared [NiCl2(1-ethyl-3-methylimidazol-2-yl)]( m [tppts-Na3] (0.012 mmol) was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 40 mg potassium bicarbonate (0.4 mmol). Hydrogenation was carried out at 80 °C and 40 bar H2 pressure. HPLC yielded 0.1 mM and 0.2 mM formate salts after 2 h and 4 h of reaction time, respectively.

[0209] iii. Metal complex: [NiCl2(1-ethyl-3-methylimidazol-2-ylidene)] (A); 10 mg of [NiCl2(1-ethyl-3-methylimidazol-2-yl)] was weighed and added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.28 mM formate was obtained by HPLC after a reaction time of 18 hours.

[0210] iv. Metal complex: [NiCl2(1-ethyl-3-methylimidazol-2-yl)] (A); Pws: m tppts-Na3 Weigh out 20 mg of [NiCl2(1-ethyl-3-methylimidazol-2-ylidene)] and 20 mg of... m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 6.06 mM formate was obtained by HPLC after a reaction time of 2 hours.

[0211] v. Metal complex: [NiCl2(1-ethyl-3-methylimidazol-2-yl)] (A); Pws: m tppms-Na Weigh out 40 mg of [NiCl2(1-ethyl-3-methylimidazol-2-ylidene)] and 40 mg of... m tppms-Na was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 1.18 mM formate was obtained by HPLC after a reaction time of 2 hours.

[0212] vi. Metal complex: [NiCl2(1-ethyl-3-methylimidazol-2-ylene) ( m tppms-Na)](A;Pws: m tppts-Na3 Weigh 10 mg of [NiCl2(1-ethyl-3-methylimidazol-2-yl)]( m tppms-Na)] and 20mg m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.54 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0213] vii. Metal complex: [NiCl2(1-butyl-3-methylimidazol-2-ylidene)] (A); Pws: m tppts-Na3 Weigh out 13 mg [NiCl2(1-butyl-3-methylimidazol-2-ylidene)] and 20 mg m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 0.66 mM and 1.14 mM formate after 2 h and 5 h of reaction time, respectively.

[0214] viii. Metal complex: [NiCl2(1-butyl-3-methylimidazol-2-ylidene))( m tppts-Na3)](A; Weigh 10 mg of [NiCl2(1-butyl-3-methylimidazol-2-ylidene))( m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.44 mM formate was obtained by HPLC after a reaction time of 20 hours.

[0215] ix. Metal complex: [NiCl2(1-butyl-3-methylimidazolium-2-ylidene) ( m tppms-Na)](A;Pws: m tppts-Na3 Weigh 20 mg of [NiCl2(1-butyl-3-methylimidazol-2-ylidene)] m tppms-Na)] and 20mg m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.37 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0216] x. Metal complex: [NiCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onth-3-yl)(phenyl)nitrogen hybrid)] (A); Pws: m tppts-Na3 Weigh out 7.5 mg of [NiCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid] and ... m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 0.252 mM and 0.342 mM formate salts after 4 h and 17 h of reaction time, respectively.

[0217] xi. Metal complex: [NiCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid) m tppts-Na3)](A; Weigh 20 mg of [NiCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid compound) m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 0.303 mM and 0.349 mM formate after 4 h and 17 h of reaction time, respectively.

[0218] Example 16: Study on the role of manganese complex catalysts in hydrogenation processes i. Metal complex: [MnCl2(1-ethyl-3-methylimidazol-2-yl))( m tppts-Na3)](A; Weigh 10 mg of the previously prepared [MnCl2(1-ethyl-3-methylimidazol-2-yl) ( m [0.012 mmol of potassium bicarbonate (tppts-Na3)] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 40 mg of potassium bicarbonate (0.4 mmol). Hydrogenation was carried out at 80 °C and 40 bar H2 pressure. 0.1 mM and 0.2 mM formate were obtained by HPLC after 19 h and 4 h of reaction time, respectively.

[0219] ii. Metal complexes: [MnCl2( m tppts-Na3)2](A; Weigh 15 mg of the previously prepared [MnCl2( m[tppts-Na3)2] (0.016 mmol) was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 100 mg potassium bicarbonate (1 mmol). Hydrogenation was carried out at 80 °C and 40 bar H2 pressure. 0.9–1.0 mM formate was obtained by HPLC after a reaction time of 2 hours.

[0220] iii. Metal complex: [MnCl2(1-ethyl-3-methylimidazol-2-yl)] (A); Pws: m tppts-Na3 Weigh out 20 mg of [MnCl2(1-ethyl-3-methylimidazol-2-ylidene)] and 20 mg of... m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.45 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0221] iv. Metal complex: [MnCl2(1-ethyl-3-methylimidazol-2-yl)] (A); Pws: m tppts-Na3 Weigh out 40 mg of [MnCl2(1-ethyl-3-methylimidazol-2-ylidene)] and 40 mg of... m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 2.08 mM formate was obtained by HPLC after a reaction time of 17 hours.

[0222] v. Metal complex: [MnCl2(1-ethyl-3-methylimidazol-2-yl)] (A); Pws: m tppms-Na Weigh out 20 mg of [MnCl2(1-ethyl-3-methylimidazol-2-ylidene)] and 20 mg of... m tppms-Na was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.24 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0223] vi. Metal complex: [MnCl2(1-ethyl-3-methylimidazol-2-yl)] (A); Pws:m tppms-Na Weigh out 40 mg of [MnCl2(1-ethyl-3-methylimidazol-2-ylidene)] and 40 mg of... m tppms-Na was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 1.19 mM and 3.72 mM formate after 4 h and 66 h of reaction time, respectively.

[0224] vii. Metal complex: [MnCl2(1-ethyl-3-methylimidazol-2-yl))( m tppms-Na)](A;Pws: m tppts-Na3 Weigh 20 mg of [MnCl2(1-ethyl-3-methylimidazol-2-yl) () m tppms-Na)] and 20mg m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.31 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0225] viii. Metal complex: [MnCl2(1-butyl-3-methylimidazol-2-ylidene)] (A); Pws: m tppts-Na3 Weigh out 20 mg of [MnCl2(1-butyl-3-methylimidazol-2-ylidene)] and 20 mg of... m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.77 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0226] ix. Metal complex: [MnCl2(1-butyl-3-methylimidazolium-2-yl))( m tppms-Na)](A;Pws: m tppts-Na3 Weigh 20 mg of [MnCl2(1-butyl-3-methylimidazol-2-ylidene)] m tppms-Na)] and 20mg mtppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.32 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0227] x. Metal complex: [MnCl2(1-butyl-3-methylimidazol-2-ethylenedimethyl)] m tppts-Na3)](A;Pws: m tppms-Na Weigh 20 mg of [MnCl2(1-butyl-3-methylimidazol-2-ylidene)] m tppts-Na3)] and 20mg m tppms-Na was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.54 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0228] xi. Metal complex: [MnBr(CO)4(1-ethyl-3-methylimidazol-2-ylidene)] (B); 50 mg of [MnBr(CO)4(1-ethyl-3-methylimidazol-2-yl)] was weighed and added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 1.35 mM formate was obtained by HPLC after a reaction time of 17 hours.

[0229] xii. Metal complex: [MnBr(CO)4(1-ethyl-3-methylimidazol-2-ylidene)] (B); Pws: m tppts-Na3 Weigh out 20 mg of [MnBr(CO)4(1-ethyl-3-methylimidazol-2-ylidene)] and 20 mg of... m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 2.61 mM formate was obtained by HPLC after a reaction time of 17 hours.

[0230] xiii. Metal complex: [MnBr(CO)3(1-ethyl-3-methylimidazol-2-ylene))(m tppms-Na)](B;Pws: m tppts-Na3 Weigh 20 mg of [MnBr(CO)3(1-ethyl-3-methylimidazol-2-ylidene))( m tppms-Na)] and 20mg m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.57 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0231] xiv. Metal complex: [MnBr(CO)2(1-ethyl-3-methylimidazol-2-yl))( m tppms-Na)2](B;Pws: m tppts-Na3 Weigh 20 mg of [MnBr(CO)2(1-ethyl-3-methylimidazol-2-yl) () m tppms-Na)2] and 20mg m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 1.78 mM formate was obtained by HPLC after a reaction time of 20 hours.

[0232] xv. Metal complex: [MnCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid) m tppts-Na3)](E) Weigh 23 mg of the previously prepared [MnCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl) nitrogen hybrid) m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 2.0316 mM formate was obtained by HPLC over 25 hours.

[0233] xvi. Metal complexes: [MnCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid) m tppms-Na)](E) Weigh 40 mg of the previously prepared [MnCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl) nitrogen hybrid) m [tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 2.6511 mM formate was obtained by HPLC over 66 hours.

[0234] Example 17: Study on the role of iron complex catalysts in hydrogenation processes i. Metal complex: [FeCl2(1-ethyl-3-methylimidazol-2-yl))( m tppts-Na3)](A; Weigh 10 mg of the previously prepared [FeCl2(1-ethyl-3-methylimidazol-2-yl)]( m [tppts-Na3] (0.012 mmol) was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 40 mg potassium bicarbonate (0.4 mmol). Hydrogenation was carried out at 80 °C and 40 bar H2 pressure. HPLC yielded 0.8 mM and 1.2 mM formate salts after 17 h and 19 h of reaction time, respectively.

[0235] ii. Metal complex: [FeCl2(1-butyl-3-methylimidazolium-2-ylidene))( m tppts-Na3)2](A; Weigh 20 mg of [FeCl2(1-butyl-3-methylimidazol-2-ylidene))( m [tppts-Na3)2] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 12.26 mM formate was obtained by HPLC after a reaction time of 4 hours.

[0236] iii. Metal complex: [FeCl2(1-butyl-3-methylimidazolium-2-yl))( m tppts-Na3)2](A;Pws: m tppts-Na3 Weigh 20 mg of [FeCl2(1-butyl-3-methylimidazol-2-ylidene))( m tppts-Na3)2] and 20mg mtppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 3.23 mM formate was obtained by HPLC after a reaction time of 17 hours.

[0237] iv. Metal complex: [FeCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid)] (E); Pws: m tppts-Na3 Weigh out 20 mg of [FeCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid)] and 20 mg of [FeCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid)]. m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 1.93 mM and 2.25 mM formate after 3 h and 18 h of reaction time, respectively.

[0238] v. Metal complex: [FeCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid) m tppts-Na3)](E; Weigh 11 mg of [FeCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid compound)( m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 0.336 mM and 0.444 mM formate after 3 h and 18 h of reaction time, respectively.

[0239] Example 18: Study on the application of lanthanum complex catalysts in hydrogenation i. Metal complex: [LaCl3(1-butyl-3-methylimidazol-2-ylidene)] (A); 20 mg of the previously prepared [LaCl3(1-butyl-3-methylimidazolium-2-yl)] was weighed and added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 0.17 mM and 0.32 mM formate salts after 4 h and 18 h of reaction time, respectively.

[0240] ii. Metal complex: [LaCl3(1-ethyl-3-methylimidazol-2-yl) () m tppms-Na)](A; Weigh 10 mg of the previously prepared [LaCl3(1-ethyl-3-methylimidazol-2-yl)]( m [tppms-Na] (0.013 mmol) was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.27 mM formate was obtained by HPLC after a reaction time of 42 hours.

[0241] iii. Metal complex: [LaCl3(1-ethyl-3-methylimidazol-2-yl) () m tppts-Na3)](A; Weigh 40 mg of the previously prepared [LaCl3(1-ethyl-3-methylimidazol-2-yl)]( m [0.04 mmol of potassium bicarbonate (tppts-Na3)] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.76 mM formate was obtained by HPLC after a reaction time of 42 hours.

[0242] iv. Metal complex: [LaCl3(1-butyl-3-methylimidazol-2-yl)] m tppts-Na3)](A; Weigh 46 mg of the previously prepared [LaCl3(1-butyl-3-methylimidazol-2-yl)]( m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.15 mM formate was obtained by HPLC after a reaction time of 17 hours.

[0243] v. Metal complex: [LaCl3(1-butyl-3-methylimidazol-2-yl))( m tppms-Na)](A; Weigh 20 mg of the previously prepared [LaCl3(1-butyl-3-methylimidazol-2-yl)]( m [tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.09 mM formate was obtained by HPLC after a reaction time of 17 hours.

[0244] vi. Metal complex: [LaCl3(1,4-diphenyl-1H-1,2,4-triazol-4-onth-3-yl)(phenyl)nitrogen hybrid)] (E); Pws: m tppts-Na3 Weigh out 40 mg of [LaCl3(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid)] and 40 mg of [LaCl3(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid ...]. m tppts-Na3 were added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2.0 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded formate at 2.3474 mM and 4.007 mM after reaction times of 3 h and 18 h, respectively.

[0245] Example 19: Study on the application of tin complex catalysts in hydrogenation i. Metal complex: [SnCl2(1-ethyl-3-methylimidazol-2-yl))( m tppms-Na)](A; Weigh 67 mg of the previously prepared [SnCl2(1-ethyl-3-methylimidazol-2-yl) ( m [tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 0.08 mM and 0.18 mM formate after 4 h and 17 h of reaction time, respectively.

[0246] ii. Metal complex: [SnCl2(1-butyl-3-methylimidazolium-2-yl))( m tppms-Na)](A; Weigh 40 mg of the previously prepared [SnCl2(1-butyl-3-methylimidazolium-2-ylidene) ( m [tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.336 mM formate was obtained by HPLC over 17 hours.

[0247] iii. Metal complex: [SnCl2(1-butyl-3-methylimidazolium-2-yl))( m tppts-Na3)](A; Weigh 40 mg of the previously prepared [SnCl2(1-butyl-3-methylimidazolium-2-ylidene) ( m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded 0.154 mM and 0.249 mM formate at 4 h and 18 h, respectively.

[0248] iv. Metal complex: [SnCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid) m tppts-Na3)](E) Weigh 40 mg of the previously prepared [SnCl2(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl) nitrogen hybrid) m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.1178 mM formate was obtained by HPLC over 25 hours.

[0249] Example 20: Study on the application of titanium complex catalysts in hydrogenation i. Metal complex: [TiOSO4(1-butyl-3-methylimidazol-2-ylidene))( m tppms-Na)](A; Weigh 10 mg of the previously prepared [TiOSO4(1-butyl-3-methylimidazol-2-ylidene) ( m[tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.303 mM formate was obtained by HPLC over 17 hours.

[0250] Example 21: Study on the application of vanadium complex catalysts in hydrogenation i. Metal complex: [VO3(1-ethyl-3-methylimidazol-2-ylene))( m tppms-Na)](A; Weigh 47 mg of the previously prepared [VO3(1-ethyl-3-methylimidazol-2-yl) ( m [tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.9168 mM formate was obtained by HPLC over 4 hours.

[0251] ii. Metal complex: [VO3(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid) m tppts-Na3)](E) Weigh 40 mg of the previously prepared [VO3(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl) nitrogen hybrid) m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 4.3917 mM formate was obtained by HPLC over 21 hours.

[0252] Example 22: Study on the role of chromium complex catalysts in hydrogenation processes i. Metal complex: [CrCl3(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid) m tppts-Na3)](E) Weigh 26 mg of the previously prepared [CrCl3(1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitrogen hybrid) m[tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. HPLC yielded formate at 0.6509 mM and 1.3409 mM in reaction times of 3 h and 18 h, respectively.

[0253] ii. Metal complex: [CrCl3(1-butyl-3-methylimidazol-2-ylidene)] (A); 40 mg of the previously prepared [CrCl3(1-butyl-3-methylimidazolium-2-yl)] was weighed and added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 1.1661 mM formate was obtained by HPLC over 66 hours.

[0254] Example 23: Study on the application of yttrium complex catalysts in hydrogenation i. Metal complex: [YCl3(1-ethyl-3-methylimidazol-2-ylidene)] (A); 43 mg of the previously prepared [YCl3(1-ethyl-3-methylimidazol-2-yl)] was weighed and added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg of potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 1.2663 mM formate was obtained by HPLC over 21 hours.

[0255] ii. Metal complex: [YCl3(1-ethyl-3-methylimidazol-2-yl))( m tppms-Na)](A; Weigh 40 mg of the previously prepared [YCl3(1-ethyl-3-methylimidazol-2-yl)]( m [tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.4548 mM formate was obtained by HPLC over 21 hours.

[0256] iii. Metal complex: [YCl3(1-ethyl-3-methylimidazol-2-yl))( m tppts-Na3)](A; Weigh 40 mg of the previously prepared [YCl3(1-ethyl-3-methylimidazol-2-yl)]( m[tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.3322 mM formate was obtained by HPLC over 21 hours.

[0257] Example 24: Study on molybdenum complex catalysts in hydrogenation processes i. Metal complex: [MoO4(1-ethyl-3-methylimidazol-2-yl))( m tppms-Na)](A; Weigh 40 mg of the previously prepared [MoO4(1-ethyl-3-methylimidazol-2-yl) ( m [tppms-Na] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.3165 mM formate was obtained by HPLC over 66 hours.

[0258] ii. Metal complex: [MoO4(1-ethyl-3-methylimidazol-2-yl))( m tppts-Na3)](A; Weigh 40 mg of the previously prepared [MoO4(1-ethyl-3-methylimidazol-2-yl) ( m [tppts-Na3] was added to 20.0 mL of pre-bubbled N2 water in a 100 mL reactor, followed by the addition of 200 mg potassium bicarbonate (2 mmol). Hydrogenation was carried out at 80 °C and 30 bar H2 pressure. A 0.078 mM formate was obtained by HPLC over 66 hours.

[0259] Industrial applicability The catalysts and methods described in this specification provide an economically advantageous and cost-effective means for implementing hydrogen storage and release systems suitable for storing hydrogen produced from renewable resources, preferably by implementing hydrogen storage and release in a single system (hydrogen accumulator) in the presence of the same catalyst. The hydrogen release system ensures the production of CO-free hydrogen. x The byproduct hydrogen gas enables hydrogen storage and release systems to operate without the need for continuous or cyclical addition of auxiliary materials (acids or bases).

Claims

1. Use of a separated or non-separated (in-situ generated) catalyst comprising a central metal M and at least one strong σ-donor ligand in a process for storing hydrogen and / or in a process for releasing hydrogen, said strong σ-donor ligand being selected from the group consisting of NHCN-heterocyclic carbene ligands and Pws water-soluble phosphine ligands, wherein hydrogen storage and hydrogen release are based on a formate-bicarbonate equilibrium, wherein: M is selected from non-platinum transition metals, p-block metals, and f-block metals; NHC is an N-heterocyclic carbene ligand, preferably selected from the group consisting of: (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron, 1-R 1 -3-R 2 -imidazol-2-subunit, 1-R 1 -3-R 2 -imidazoline-2-subunit and 1-R 1 -3-R 2 -benzimidazole-2-subunit, where R 1 and R 2 Each of the following is a straight-chain or branched alkyl, benzyl or phenyl group having 1 to 6 carbon atoms, which is either unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms. Pws is a water-soluble phosphine ligand, selected from the group consisting of the following: The general formula is PR 1 R 2 R 3 Tertiary phosphine, of which R 1 R 2 and R 3 Independently, it is a straight-chain or branched alkyl or phenyl group with 1 to 5 carbon atoms, wherein the alkyl group may be substituted with an OH group or a sulfonic acid group, and the phenyl group may be substituted with an alkyl group and / or a sulfonic acid group with 1 to 6 carbon atoms, provided that R 1 R 2 and R 3 At least one of them contains an OH group or a sulfonic acid group; or cyclic tertiary phosphine; or The general formula is R 4 2P-bridge-PR 5 2-diphosphine, where R 4 and R 5 Independently, it is a straight-chain or branched alkyl or phenyl group with 1 to 5 carbon atoms, wherein the alkyl group may be substituted with an OH group or a sulfonic acid group, and the phenyl group may be substituted with an alkyl group or a sulfonic acid group with 1 to 6 carbon atoms. 4 2 and PR 5 2 can have the same or different meanings, provided that R 4 and R 5 At least one of them contains an OH group or a sulfonic acid group; wherein the bridging group is a straight-chain alkylene group with 1 to 6 carbon atoms, preferably methylene, ethylene, propylene, butylene, or hexylene; or Diphosphine, which contains cyclic tertiary phosphine groups bridged by covalent bonds.

2. The use according to claim 1, wherein M in the catalyst is selected from the group consisting of non-platinum transition metals, lanthanum, and tin.

3. The use according to claim 2, wherein M in the catalyst is selected from the group consisting of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, yttrium, molybdenum, lanthanum and tin.

4. The use according to claim 2, wherein M in the catalyst is selected from the group consisting of non-platinum transition metals.

5. The use according to claim 4, wherein M in the catalyst is selected from the group consisting of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, yttrium and molybdenum.

6. The use according to any one of claims 1 to 5, wherein the NHC in the catalyst is selected from the group consisting of: (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron, 1,3-dimethylimidazol-2-yl, 1-ethyl-3-methylimidazol-2-yl (emim), 1-methyl-3-propylimidazol-2-yl, 1-butyl-3-methylimidazol-2-yl (bmim), 1-methyl-3-pentylimidazol-2-yl, 1,3-diethylimidazol-2-yl, 1-ethyl-3-propylimidazol-2-yl, 1-ethyl-3-butylimidazol-2-yl, 1-ethyl -3-pentylimidazol-2-ylene, 1,3-dipropylimidazol-2-ylene, 1-propyl-3-butylimidazol-2-ylene, 1-propyl-3-pentylimidazol-2-ylene, 1,3-dibutylimidazol-2-ylene, 1-butyl-3-pentylimidazol-2-ylene, 1,3-dipentylimidazol-2-ylene, 1,3-diisopropylimidazol-2-ylene, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylene, 1-methyl-3-phenylimidazol-2-ylene, 1-ethyl-3-phenylimidazol-2-ylene, 1-propyl-3-phenylimidazol-2-ylene, 1-butyl-3-phenylimidazol-2-ylene, 1-pentyl-3-phenylimidazol-2-ylene, 1 3-Diphenylimidazolium-2-ylene, 1-benzyl-3-methylimidazolium-2-ylene (Bnmim), 1-hexyl-3-methylimidazolium-2-ylene (hexmim), 1,3-dimethylimidazoline-2-ylene, 1-methyl-3-ethylimidazoline-2-ylene, 1-methyl-3-propylimidazoline-2-ylene, 1-methyl-3-butylimidazoline-2-ylene, 1-methyl-3-pentylimidazoline-2-ylene, 1,3-diethylimidazoline-2-ylene, 1-ethyl-3-propylimidazoline-2-ylene, 1-ethyl-3-butylimidazoline-2-ylene, 1-ethyl-3-pentylimidazoline-2-ylene, 1,3-dipropylimidazoline-2-ylene 1-propyl-3-butylimidazoline-2-ylene, 1-propyl-3-pentylimidazoline-2-ylene, 1,3-dibutylimidazoline-2-ylene, 1-butyl-3-pentylimidazoline-2-ylene, 1,3-dipentylimidazoline-2-ylene, 1,3-diisopropylimidazoline-2-ylene, 1,3-bis(2,4,6-trimethylphenyl)imidazoline-2-ylene, 1-methyl-3-phenylimidazoline-2-ylene, 1-ethyl-3-phenylimidazoline-2-ylene, 1-propyl-3-phenylimidazoline-2-ylene, 1-butyl-3-phenylimidazoline-2-ylene, 1-pentyl-3-phenylimidazoline-2-ylene, 1,3-diphenylimidazoline-2-ylene, 1,3-Dimethylbenzimidazole-2-ylene, 1-Methyl-3-ethylbenzimidazole-2-ylene, 1-Methyl-3-propylbenzimidazole-2-ylene, 1-Methyl-3-butylbenzimidazole-2-ylene, 1-Methyl-3-pentylbenzimidazole-2-ylene, 1,3-Diethylbenzimidazole-2-ylene, 1-Ethyl-3-propylbenzimidazole-2-ylene, 1-Ethyl-3-butylbenzimidazole-2-ylene, 1-Ethyl-3-pentylbenzimidazole-2-ylene, 1,3-Dipropylbenzimidazole-2-ylene, 1-Propyl-3-butylbenzimidazole-2-ylene, 1-Propyl-3-pentylbenzimidazole- 2-Acetyl, 1,3-dibutylbenzimidazole-2-acetyl, 1-butyl-3-pentylbenzimidazole-2-acetyl, 1,3-dipentylbenzimidazole-2-acetyl, 1,3-diisopropylbenzimidazole-2-acetyl, 1,3-bis(2,4,6-trimethylphenyl)benzimidazole-2-acetyl, 1-methyl-3-phenylbenzimidazole-2-acetyl, 1-ethyl-3-phenylbenzimidazole-2-acetyl, 1-propyl-3-phenylbenzimidazole-2-acetyl, 1-butyl-3-phenylbenzimidazole-2-acetyl, 1-pentyl-3-phenylbenzimidazole-2-acetyl and 1,3-diphenylbenzimidazole-2-acetyl.

7. The use according to any one of claims 1 to 6, wherein the Pws in the catalyst is selected from the group consisting of: The general formula is PR 1 R 2 R 3 Tertiary phosphine, selected from the group consisting of: P(CH2OH)3[tris(hydroxymethyl)phosphine]; Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the ortho position ( o tppms, o tppds, o tppts), Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the meta position ( m tppms, m tppds, m tppts), or Li, Na, K or Cs salts of triphenylphosphine monosulfonated at the para position ( p tppms); and 1,3,5-Triaza-7-phosphaadamantane (pta).

8. The use according to any one of claims 1 to 6, wherein the Pws in the catalyst is selected from the group consisting of: The general formula is R 4 2P-bridge-PR 5 2 phosphine, of which PR 4 2 and PR 5 2 is independently selected from: P(CH2OH)2 (bis(hydroxymethyl)phosphino), PPh2 (diphenylphosphino), Li, Na, K, or Cs salts of diphenylphosphino monosulfonated or disulfonated at the ortho position, Li, Na, K, or Cs salts of diphenylphosphino monosulfonated or disulfonated at the meta position, Li, Na, K, or Cs salts of diphenylphosphino monosulfonated or disulfonated at the para position, where "bridge" represents an alkylene group with 1 to 6 carbon atoms; and According to the compound of formula (4): Equation (4) In equation (4), m is an integer from 1 to 6.

9. The use according to claim 7, wherein the Pws in the catalyst is selected from the group consisting of: Li, Na, K, or Cs salts of triphenylphosphine monosulfonated, disulfonated, or trisulfonated at the meta position (…). m tppms, m tppds, m tppts), 1,3,5-triaza-7-phosphaadamantane (pta).

10. The use according to claim 8, wherein the Pws in the catalyst is selected from the group consisting of tetrasulfonated 1,2-bis(diphenylphosphino)ethane (dppets), tetrasulfonated 1,3-bis(diphenylphosphino)propane (dpppts), and compounds of formula (4).

11. The use according to any one of claims 1 to 10, wherein the NHC in the catalyst is selected from the group consisting of: 1-ethyl-3-methylimidazolium-2-yl (emim), 1-butyl-3-methylimidazolium-2-yl (bmim), 1-hexyl-3-methylimidazolium-2-yl (hexmim), and 1-benzyl-3-methylimidazolium-2-yl (Bnmim), and (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron.

12. The use according to any one of claims 1 to 11, wherein the catalyst is represented by general formula (I), (II) or (III): [M(NHC) n (Pws) p (L 1 ) q (L 2 ) r ](I), or [Fe3(NHC) n' (Pws) p' (L 1 ) q' (L 2 ) r' ](II), or [Co2(NHC) n" (Pws) p" (L 1 ) q" (L 2 ) r" ](III), in, M, NHC and Pws are as defined in any one of claims 1 to 11; L 1 For negatively charged ligands, the preferred choice is from the group consisting of: H - F - Cl - ,Br - I - OH - BF4 - PF6 - HCO3 - (bicarbonate), HCO2 - (Formate), CH3CO2 - (Acetate), [CH3COCHCOCH3] - (Acetylacetone), cyanide, isocyanate, nitrite, nitrate, thiocyanate, isothiocyanate, SO4² - and O² - ; L 2 The ligand is a neutral (nonionic) ligand selected from the group consisting of: H₂O; CO (carbonyl); MeOH; dimethyl sulfoxide or acetonitrile; a 5- to 10-membered ring cyclodiene, optionally substituted with one or more substituents selected from alkyl and phenyl groups of 1 to 5 carbon atoms; a 6- to 10-carbon π-donor aromatic ligand; and In general formula (I), n, p, q and r are 0, 1, 2, 3 or 4, provided that n+p is at least 1 and n+p+q+r ≤ 8; In general formula (II), n' is 0 or 1, p' is 1, 2 or 3, q' is 0, and r' = 12-n'-q'-r'-p'; In general formula (III), n" is 0 or 1, p" is 1 or 2, q" is 0, and r" = 8-n"-q"-r"-p"; Where n, p, q, r, n', p', q', r', n", p", q" and / or r" are greater than 1, then NHC, Pws, L 1 and / or L 2 They can be the same or different.

13. The use according to claim 12, wherein L 1 For H - F - Cl - ,Br - I - CH3CO2 - (acetate), SO4² - or O² - ;and L 2 It can be CO, H2O, MeOH, CH3CN, or dimethyl sulfoxide.

14. The use according to any one of claims 1 to 5, wherein the catalyst is represented by general formula (I), (II) or (III): [M(NHC) n (Pws) p (L 1 ) q (L 2 ) r ](I), or [Fe3(NHC) n' (Pws) p' (L 1 ) q' (L 2 ) r' ](II), or [Co2(NHC) n" (Pws) p" (L 1 ) q" (L 2 ) r" ](III), in, NHC is selected from the group consisting of: (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl) nitron, 1,3-dimethylimidazol-2-yl, 1-ethyl-3-methylimidazol-2-yl (emim), 1-methyl-3-propylimidazol-2-yl, 1-butyl-3-methylimidazol-2-yl (bmim), 1-methyl-3-pentylimidazol-2-yl, 1,3-diethylimidazol-2-yl, 1-ethyl-3-propylimidazol-2-yl, 1-ethyl-3-butylimidazol-2-yl, 1-ethyl-3-pentylimidazol-2-yl, 1,3-dipropylimidazolium -2- imidazole, 1-propyl-3-butylimidazol-2-imidazole, 1-propyl-3-pentylimidazol-2-imidazole, 1,3-dibutylimidazol-2-imidazole, 1-butyl-3-pentylimidazol-2-imidazole, 1,3-dipentylimidazol-2-imidazole, 1,3-diisopropylimidazol-2-imidazole, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-imidazole, 1-methyl-3-phenylimidazol-2-imidazole, 1-ethyl-3-phenylimidazol-2-imidazole, 1-propyl-3-phenylimidazol-2-imidazole, 1-butyl-3-phenylimidazol-2-imidazole, 1-pentyl-3-phenylimidazol-2-imidazole, 1,3-diphenylimidazol-2-imidazole, 1 Benzyl-3-methylimidazolium-2-ylene (Bnmim), 1-hexyl-3-methylimidazolium-2-ylene (hexmim), 1,3-dimethylimidazolium-2-ylene, 1-methyl-3-ethylimidazolium-2-ylene, 1-methyl-3-propylimidazolium-2-ylene, 1-methyl-3-butylimidazolium-2-ylene, 1-methyl-3-pentylimidazolium-2-ylene, 1,3-diethylimidazolium-2-ylene, 1-ethyl-3-propylimidazolium-2-ylene, 1-ethyl-3-butylimidazolium-2-ylene, 1-ethyl-3-pentylimidazolium-2-ylene, 1,3-dipropylimidazolium-2-ylene, 1-propyl-3-butylimidazolium 1,3-dibutylimidazoline-2-ylene, 1-propyl-3-pentylimidazoline-2-ylene, 1,3-dibutylimidazoline-2-ylene, 1-butyl-3-pentylimidazoline-2-ylene, 1,3-dipentylimidazoline-2-ylene, 1,3-diisopropylimidazoline-2-ylene, 1,3-bis(2,4,6-trimethylphenyl)imidazoline-2-ylene, 1-methyl-3-phenylimidazoline-2-ylene, 1-ethyl-3-phenylimidazoline-2-ylene, 1-propyl-3-phenylimidazoline-2-ylene, 1-butyl-3-phenylimidazoline-2-ylene, 1-pentyl-3-phenylimidazoline-2-ylene, 1,3-diphenylimidazoline-2-ylene, 1,3-Dimethylbenzimidazole-2-ylene, 1-Methyl-3-ethylbenzimidazole-2-ylene, 1-Methyl-3-propylbenzimidazole-2-ylene, 1-Methyl-3-butylbenzimidazole-2-ylene, 1-Methyl-3-pentylbenzimidazole-2-ylene, 1,3-Diethylbenzimidazole-2-ylene, 1-Ethyl-3-propylbenzimidazole-2-ylene, 1-Ethyl-3-butylbenzimidazole-2-ylene, 1-Ethyl-3-pentylbenzimidazole-2-ylene, 1,3-Dipropylbenzimidazole-2-ylene, 1-Propyl-3-butylbenzimidazole-2-ylene, 1-Propyl-3-pentylbenzimidazole-2-ylene - Subunits, 1,3-dibutylbenzimidazole-2-subunits, 1-butyl-3-pentylbenzimidazole-2-subunits, 1,3-dipentylbenzimidazole-2-subunits, 1,3-diisopropylbenzimidazole-2-subunits, 1,3-bis(2,4,6-trimethylphenyl)benzimidazole-2-subunits, 1-methyl-3-phenylbenzimidazole-2-subunits, 1-ethyl-3-phenylbenzimidazole-2-subunits, 1-propyl-3-phenylbenzimidazole-2-subunits, 1-butyl-3-phenylbenzimidazole-2-subunits, 1-pentyl-3-phenylbenzimidazole-2-subunits, and 1,3-diphenylbenzimidazole-2-subunits; Pws selects from the following groups: The general formula is PR 1 R 2 R 3 Tertiary phosphine, selected from the group consisting of: P(CH2OH)3[tris(hydroxymethyl)phosphine]; Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the ortho position ( o tppms, o tppds, o tppts); Li, Na, K or Cs salts of triphenylphosphine monosulfonated, disulfonated or trisulfonated at the meta position ( m tppms, m tppds, m tppts); And Li, Na, K or Cs salts of triphenylphosphine monosulfonated at the para position ( p tppms); 1,3,5-Triaza-7-phosphaadamantane (pta); The general formula is R 4 2P-bridge-PR 5 2 phosphine, of which PR 4 2 and PR 5 2. Independently selected from: P(CH2OH)2 (bis(hydroxymethyl)phosphin); PPh2 (diphenylphosphin); Li, Na, K or Cs salts of diphenylphosphin monosulfonated or disulfonated at the ortho position; Li, Na, K or Cs salts of diphenylphosphin monosulfonated or disulfonated at the meta position; Li, Na, K or Cs salts of diphenylphosphin monosulfonated or disulfonated at the para position; as well as Compounds of formula (4): (4)， Where m is an integer from 1 to 6; L 1 Choose from the following groups: H - F - Cl - ,Br - I - OH - BF4 - PF6 - HCO3 - (bicarbonate), HCO2 - (Formate), CH3CO2 - (Acetate), [CH3COCHCOCH3] - (Acetylacetone), cyanide, isocyanate, nitrite, nitrate, thiocyanate, isothiocyanate, SO4² - and O² - ; L 2 It can be CO, H2O, MeOH, CH3CN, or dimethyl sulfoxide; In general formula (I), n, p, q and r are 0, 1, 2, 3 or 4, provided that n+p is at least 1 and n+p+q+r ≤ 8; In general formula (II), n' is 0 or 1, p' is 1, 2 or 3, q' is 0, and r' = 12-n'-q'-r'-p'; In general formula (III), n" is 0 or 1, p" is 1 or 2, q" is 0, and r" = 8-n"-q"-r"-p"; Where n, p, q, r, n', p', q', r', n", p", q" and / or r" are greater than 1, then NHC, Pws, L 1 and / or L 2 They can be the same or different.

15. The use according to claim 14, wherein in formula (I), (II) or (III), NHC is 1-ethyl-3-methylimidazolium-2-ylene (emim), 1-butyl-3-methylimidazolium-2-ylene (bmim), 1-hexyl-3-methylimidazolium-2-ylene (hexmim), 1-benzyl-3-methylimidazolium-2-ylene (Bnmim) or (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl) nitrogen hybrid (nitron); Pws is a Li, Na, K, or Cs salt of triphenylphosphine monosulfonated, disulfonated, or trisulfonated at the meta position. m tppms, m tppds, m tppts), or 1,3,5-triaza-7-phosphaadamantane (pta), tetrasulfonated 1,2-bis(diphenylphosphino)ethane (dppets), tetrasulfonated 1,3-bis(diphenylphosphino)propane (dpppts) or compounds of formula (4): (4)， Where m is an integer from 1 to 6, L 1 For H - F - Cl - ,Br - I - CH3CO2 - (acetate), SO4² - or O² - ;and L 2 It can be CO, H2O, MeOH, CH3CN, or dimethyl sulfoxide.

16. The use according to claim 15, wherein in the catalyst of general formula (I), (II) or (III), NHC is 1-ethyl-3-methylimidazolium-2-ylene (emim), 1-butyl-3-methylimidazolium-2-ylene (bmim), 1-hexyl-3-methylimidazolium-2-ylene (hexmim), 1-benzyl-3-methylimidazolium-2-ylene (Bnmim) or (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl) nitrogen hybrid (nitron); Pws is a Li, Na, K, or Cs salt of triphenylphosphine monosulfonated, disulfonated, or trisulfonated at the meta position. m tppms, m tppts), or 1,3,5-triaza-7-phosphaadamantane (pta); L 1 For Cl - ,Br - CH3CO2 - SO4² - or O² - ;and L 2 It is either CO or H2O.

17. The use according to any one of claims 14 to 16, wherein in the catalyst of general formula (I), n and p are 0, 1 or 2, q is 0, 1, 2, 3 or 4, and r is 0, 1, 2, 3 or 4, provided that n+p is at least 1 and n+p+q+r ≤ 8.

18. The use according to any one of claims 1 to 5, wherein the catalyst is a catalyst produced in situ using the following substances: A water-soluble salt of metal M, and at least 1 equimolar amount of NHC precursor and / or Pws ligand relative to the metal ion. in, M and Pws are as defined in any one of claims 1 to 5; The NHC precursor is an N-heterocyclic carbene precursor compound, preferably selected from the group consisting of: (1,4-diphenyl-1H-1,2,4-triazol-4-onthium-3-yl)(phenyl)nitron, 1-R 1 -3-R 2 -Imidazolium salts, 1-R 1 -3-R 2 -Imidazolinium salts and 1-R 1 -3-R 2 - A salt of benzimidazolium, wherein R 1 and R 2 Each is independently a straight-chain or branched alkyl, benzyl, or phenyl group having 1 to 6 carbon atoms, which is either unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms.

19. The use according to claim 18, wherein for the production of the non-separated catalyst, the catalyst used... NHC precursors are selected from the group consisting of: 1-ethyl-3-methylimidazolium chloride (emimCl), 1-butyl-3-methylimidazolium chloride (bmimCl), 1-hexyl-3-methylimidazolium chloride (hexmimCl), 1-benzyl-3-methylimidazolium chloride (BnmimCl), 1-ethyl-3-methylimidazolium acetate (emimAc), 1-butyl-3-methylimidazolium acetate (bmimAc), 1-hexyl-3-methylimidazolium acetate (hexmimAc), 1-benzyl-3-methylimidazolium acetate (BnmimAc), and (1,4-diphenyl-1H-1,2,4-triazol-4-on-3-yl)(phenyl)nitron; Pws is selected from the group consisting of: Li, Na, K, or Cs salts of triphenylphosphine monosulfonated, disulfonated, or trisulfonated at the meta position ( m tppms, m tppds, m tppts), or 1,3,5-triaza-7-phosphaadamantane (pta).

20. The use according to claim 18 or 19, wherein the NHC precursor and / or Pws ligand in at least 1 equimolar amount relative to the metal ion M for forming the non-separated catalyst is 0-10 equimolar amounts of NHC precursor and 0-10 equimolar amounts of Pws ligand relative to the metal ion M, preferably 0-6 equimolar amounts of NHC precursor and 0-6 equimolar amounts of Pws ligand, more preferably 1-6 equimolar amounts of NHC precursor and / or Pws ligand.

21. A process for releasing hydrogen, wherein the process comprises decomposing a formate in an aqueous reaction system in the presence of a catalyst as defined in any one of claims 1 to 20 to produce a CO-free product. x The byproduct hydrogen gas, wherein the formate is preferably sodium formate (HCO2Na), lithium formate (HCO2Li), cesium formate (HCO2Cs) and / or potassium formate (HCO2K). The decomposition of the formate is carried out in an anaerobic atmosphere at an elevated temperature and at a pH greater than 8, wherein the elevated temperature is preferably 60-100°C, more preferably 60-80°C, and the pH is preferably pH=8.3±0.

2.

22. A process for storing hydrogen, wherein the process includes reacting bicarbonate (HCO3-) in an aqueous reaction system in the presence of a catalyst as defined in any one of claims 1 to 20. - The bicarbonate is hydrogenated to produce formate, wherein the bicarbonate is preferably sodium bicarbonate (NaHCO3), lithium bicarbonate (LiHCO3), cesium bicarbonate (CsHCO3) and / or potassium bicarbonate (KHCO3), and the formate is preferably sodium formate (HCO2Na), lithium formate (HCO2Li), cesium formate (HCO2Cs) and / or potassium formate (HCO2K). The hydrogenation step of the bicarbonate is carried out in an oxygen-free atmosphere at an elevated temperature and an H2 pressure of 1-1200 bar, wherein the elevated temperature is preferably 60-100°C, more preferably 80°C, and the H2 pressure is preferably 10-100 bar, more preferably 30-40 bar, and even more preferably 30 bar or 40 bar.

23. A process for releasing and storing hydrogen, wherein the process includes the following steps: i) In an aqueous reaction system, in the presence of the catalyst as defined in any one of claims 1 to 20, decomposing formate to produce CO-free formate. x The byproduct hydrogen gas (H2), wherein the formate is preferably sodium formate (HCO2Na), lithium formate (HCO2Li), cesium formate (HCO2Cs), and / or potassium formate (HCO2K); and ii) In an aqueous reaction system, in the presence of the catalyst used in step i), the bicarbonate (HCO3) produced in step i) is reacted... - The bicarbonate is hydrogenated to produce a formate, wherein the bicarbonate is preferably sodium bicarbonate (NaHCO3), lithium bicarbonate (LiHCO3), cesium bicarbonate (CsHCO3), and potassium bicarbonate (KHCO3), and the formate is preferably sodium formate (HCO2Na), lithium formate (HCO2Li), cesium formate (HCO2Cs), and / or potassium formate (HCO2K). The decomposition of the formate is carried out in an anaerobic atmosphere at an elevated temperature and at a pH greater than 8, wherein the elevated temperature is preferably 60-100°C, more preferably 60-80°C, and the pH is preferably pH=8.3±0.

2. Furthermore, the hydrogenation step of the bicarbonate is carried out in an oxygen-free atmosphere at an elevated temperature and an H2 pressure of 1-1200 bar, wherein the elevated temperature is preferably 60-100°C, more preferably 80°C, and the H2 pressure is preferably 10-100 bar, more preferably 30-40 bar, more preferably 30 bar or 40 bar. Furthermore, the reactants and products are formed in a reversible reaction cycle of the reaction system using the formate decomposition step and the bicarbonate hydrogenation step, and this reaction cycle is optionally repeated.

24. Use of the process according to any one of claims 21 to 23 in a hydrogen storage system, preferably in a hydrogen accumulator.

Images