Alkane dehydrogenation nanocatalyst and method for preparing the same

Abstract

The present invention relates to a catalyst composition comprising nanoparticles in a sufficient porous support, said nanoparticles comprising one or more elements selected from the group of group 10 elements, a cocatalyst, a promoter and an organic molecule as an organic stabilizer. The invention also includes a specific way of making said catalyst composition as well as the use of said catalyst in the selective non-oxidative dehydrogenation of alkanes.

Description

[0001] Cross-reference with related applications

[0002] This application claims the benefit of European patent application EP21382154.9, filed on February 24, 2021. Technical Field

[0003] This invention relates to the field of nanocatalysts for non-oxidative dehydrogenation of alkanes to obtain light olefins and aromatic compounds. It also relates to the value-added processing of light hydrocarbons, primarily for use in the chemical industry. Background Technology

[0004] Currently, the production of polymer components, namely propylene and butadiene, is carried out via the cracking of fossil naphtha. Cracking generates significant CO2 emissions due to its high energy requirements (i.e., reaction temperatures of 800–1200 °C). Recently, dehydrogenation of light alkanes (C1–C8 alkanes) has emerged as a more efficient and sustainable alternative for polymer component production. To date, non-oxidative dehydrogenation (nODH) methods have been applied on an industrial scale, but success has been limited due to technological limitations (i.e., inefficient catalyst stability and thermodynamic limitations), economic limitations (i.e., high OPEX associated with rapid catalyst deactivation and regeneration cycle requirements), and sustainability limitations (i.e., significant greenhouse gas (GHG) emissions associated with poor catalyst performance and catalyst regeneration methods).

[0005] Current catalyst preparation methods are described, for example, in patent document EP0328507A1 (Fina Research). EP0328507 discloses a method for catalytic dehydrogenation of propane in the presence of hydrogen, at a molar ratio of 0.05 to 0.5 moles of hydrogen per mole of propane, on a catalyst composed of an alumina support containing at least one Group 10 metal, a co-catalyst, and a promoter. The method includes the step of passing the feed to be dehydrogenated through a catalyst containing 0.2 to 1 wt% platinum, 0.15 to 1 wt% tin as a co-catalyst, and 0.8 to 2 wt% potassium as a promoter. The catalyst is obtained by: passing the feed containing the co-catalyst and... The alumina support calcined at a temperature between 450 and 550°C is first treated with a platinum compound, followed by calcination in air and reduction in the presence of hydrogen at a temperature between 450 and 550°C; then an intermediate treatment is performed to deposit potassium, followed by calcination at a temperature between 380 and 550°C; finally, a second treatment with a platinum compound is performed, followed by calcination at a temperature not exceeding 525°C; the dehydrogenation is carried out in the presence of a catalyst at a temperature between 530°C and 650°C, 5.0 x 10⁻⁶. 4 Pa up to 3.0 x 10 5 The test was conducted under pressures between Pa and weights between 1 and 10 spacetime velocities.

[0006] Sattler et al. disclosed some catalysts used in nODH in a method commercially known as Oleflex (owned by UOP-Honeywell). In this method, propane and isobutane are dehydrogenated at 520-705 °C and 1-3 bar using a catalyst consisting of Pt nanoparticles (1 wt% of total catalyst) on an alumina (Al₂O₃) support catalyzed with Na or K (0.1 wt% of total catalyst) and also containing Sn nanoparticles (1-2 wt% of total catalyst). The catalyst provides 22% to 70% alkane conversion (yield) and propylene selectivity within 70-90%. The reaction is carried out in a fluidized bed reactor consisting of three separate sections: several reactors in series, a product recovery station, and a catalyst regeneration section. The catalyst lifetime is 1 to 3 years, thus new catalyst is continuously added to the reactor system in the Oleflex method. Using this method results in coke deposition and sintering of the Pt nanoparticles, while catalyst particle wear is attributed to the fluidized bed. This requires the removal of coke from the catalyst during regeneration (by combustion) and the addition of chlorine to help redisperse Pt in such catalysts (see Sattler et al., 2014, Catalytic Dehydrogenation of Light Alkanes on Metals and MetalOxides, Chemical Reviews vol.no.114,pp:10613-10653).

[0007] Other nanocatalysts for nODH of alkanes containing Pt and an additional metal (i.e. Ga) and exhibiting high selectivity (around 98-99%) for propylene have also been disclosed. For example, Searles et al. (2018) proposed using Ga-Pt nanocatalysts supported on SiO2 to provide high activity, selectivity, and stability in propane nODH. The catalyst was prepared by a surface organometallic chemistry method and an initial wet impregnation method, and it achieved an alkane conversion percentage of around 32% and a propylene selectivity of over 99% at 550 °C (see Searles et al., 2018, Highly Productive Propane Dehydrogenation Catalyst Using Silica-Supported Ga-Pt Nanoparticles Generated from Single-Sites, Journal of American Chemical Society 140, pp.:11674-11679).

[0008] However, most of these catalysts lose their initial catalytic activity during the regeneration cycle, as this cycle typically involves the use of aggressive conditions. Furthermore, since alkane dehydrogenation is an endothermic reaction, the catalysts are also impaired by the high temperatures required to convert propane and other alkanes to olefins (i.e., propylene). Additionally, coke formation occurs as a byproduct of the reaction, which must be burned off at high temperatures to regenerate catalytic activity. Moreover, many catalysts are obtained through complex methods involving several steps and sophisticated equipment and high temperatures.

[0009] Pt-In nanoparticles in a solid support (SIRAL) for propane dehydrogenation catalysis have also been disclosed to provide high conversion and selectivity of propylene (see Wang et al., 2017, Colloidal Synthesis of Pt-In Bimetallic Nanoparticles for Propane Dehydrogenation, Can. J. Chem 1-29). Wang et al. proposed a colloidal synthesis of bimetallic nanoparticles using polyvinylpyrrolidone (PVP) to obtain nanoparticles with uniform elemental distribution, controllable composition, and narrow particle size distribution. The synthesis of the bimetallic nanoparticles is carried out as follows: first, the support (SIRAL), solvent (diethylene glycol), and PVP are mixed; the mixture is further heated at 220 °C; then, organometallic precursors of the metal (In(acac)3 and Pt(acac)2) are added and the mixture is held at 220 °C for a period of time, and then cooled at 70 °C and maintained for 7 hours. As previously mentioned, this method produces catalysts with high conversion and selectivity. However, preparing small-sized (1-2 nm) nanoparticles in colloidal suspensions using PVP and other polymeric compounds means that significant amounts of polymer will subsequently be removed from the nanoparticle surface. This makes the synthesis process lengthy and expensive. Another drawback of using polymeric compounds such as PVP is that coke forms on the catalyst surface and deactivates it due to the high temperatures required for alkane-to-olefin conversion. Therefore, decoking and regeneration are required at even higher temperatures (i.e., exceeding 700 °C), which may otherwise shorten the catalyst's lifetime.

[0010] Although good catalysts for alkane nODH have been provided, there is still a need for other catalysts with high catalytic conversion, activity, and selectivity, and / or high catalytic conversion. Catalytic conversion is measured as the percentage of moles of compound per mole of feed into the reactor that are dehydrogenated per reactor pass (i.e., %mol / mol), which remains constant or slightly decreases with reaction time. Catalytic activity is measured as the number of moles of substrate converted per mole of catalyst active site per unit time (i.e., moles of substrate converted x moles of catalyst active site). -1 xh -1 Catalytic selectivity is measured as the percentage (i.e., %mol / mol) of the expected number of moles of the converted compound per mole of total charge per reactor pass. There remains a need for catalysts that are highly selective, reproducible, and readily available at an acceptable cost. Summary of the Invention

[0011] The inventors have proposed novel catalyst compositions or catalysts comprising nanoparticles having a metal element supported on a support, which can be used for the dehydrogenation of alkanes via nODH and for the aromatization of alkanes and cycloalkanes. These catalyst compositions can be defined as nanocatalysts (or nanocatalyst compositions) because they contain nanoparticles. Specifically, the catalyst compositions are obtained by an innovative nanofabrication method, also proposed by the inventors, for preparing more uniform nanocatalyst compositions.

[0012] Furthermore, in some embodiments, these catalysts are obtained using a one-pot reaction at relatively low temperatures (room temperature to 100°C), thus making the synthesis / production method more economical and reproducible than other methods used to obtain similar catalysts. The catalyst compositions are homogeneous and, moreover, consist of small-sized nanoparticles with extensive surface active regions. Due to their composition, the catalysts are stable and retain their catalytic activity, partly because their surfaces remain clean for extended periods (free from impurities or products deposited on their surfaces and generated by the reactions they catalyze).

[0013] The inventors have surprisingly discovered that the selection of certain metals and combinations of said metals with other elements (all of which are stabilized by specific organic compounds and adsorbed on porous supports) produces highly active catalytic surface regions. Furthermore, said surface regions are not only selective for propylene in nODH, but are also highly stable and do not have the major drawbacks of other catalysts used for the same reaction (i.e., coke formation, passivation side reactions, etc.).

[0014] Therefore, a first aspect of the present invention is a catalyst composition comprising:

[0015] (a) Metal nanoparticles; and

[0016] (b) A porous carrier having a surface region; wherein the nanoparticles (a) are adsorbed on the surface region of the porous carrier;

[0017] The nanoparticles (a) comprise: (i) one or more metal elements of Group 10 of the periodic table; (ii) one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; and (iii) one or more metal elements selected from tin (Sn), gallium (Ga) and indium (In).

[0018] The data below confirm that, for the same reaction, the proposed catalyst compositions imply higher selectivity (>99%) than commercial catalysts, even at similar conversion percentages or rates, in some embodiments. Furthermore, as previously mentioned, their catalytic activity is maintained for a longer period. Therefore, the conversion percentage is maintained or only slightly reduced in the reaction process.

[0019] Compared to certain prior art catalysts that also exhibit high selectivity (97-99%), the catalyst compositions of the present invention are produced by a simpler synthetic method than those of the prior art, requiring only one step in preparation, and are more reproducible. This reproducibility results in more reliable catalysts.

[0020] Therefore, the present invention also discloses a reliable and reproducible method for synthesizing the catalyst composition.

[0021] In a second aspect, the present invention relates to a method for preparing a catalyst composition as defined above, the method comprising, in a one-pot step, decomposing one or more organometallic precursor compounds of one or more Group 10 elements and one or more organometallic precursor compounds of one or more metal elements selected from tin (Sn), gallium (Ga), and indium (In) in the presence of an organic solvent, a porous support, and one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; said one-pot decomposition is carried out in a hydrogen atmosphere at a temperature of 20°C to 100°C and 1.0 x 10⁻⁶ ppm. 5 Pa to 5.0 x 10 5 Perform tests under Pa pressure for 30 minutes to 70 hours.

[0022] As will be described in the determinations below, the catalyst synthesized in this one-pot manner exhibits high activity due to the extremely uniform distribution of elements on the support resulting in small changes in surface area relative to the pure support (i.e., see Brunauer-Emmett-Teller (BET) values), and due to the synthesis (nanofabrication) of well-dispersed small-sized (1-15 nm, more particularly 1-5 nm) nanoparticles at the nanoscale or nanoscale, controlled by the presence of the organic molecules.

[0023] The catalyst composition can also be defined by its preparation method. Therefore, another part of the invention is a catalyst composition comprising:

[0024] (a) Metal nanoparticles; and

[0025] (b) A porous carrier having a surface region, wherein the nanoparticles (a) are adsorbed on the surface region of the porous carrier;

[0026] The nanoparticles (a) therein comprise: (i) one or more metal elements of Group 10 of the periodic table; (ii) one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; and (iii) one or more metal elements selected from tin (Sn), gallium (Ga) and indium (In);

[0027] The catalyst composition can be obtained by decomposing one or more organometallic precursor compounds of one or more Group 10 elements and one or more organometallic precursor compounds of one or more metal elements selected from tin (Sn), gallium (Ga), and indium (In) in a one-pot process in the presence of an organic solvent, a porous support, and one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; the one-pot decomposition is carried out in a hydrogen atmosphere at a temperature of 20°C to 100°C and 1.0 x 10⁻⁶ ppm. 5 Pa to 5.0 x 10 5 Perform tests under Pa pressure for 30 minutes to 70 hours.

[0028] As previously stated, the catalyst compositions described are particularly useful in the dehydrogenation of alkanes to olefins. These catalysts are highly efficient and selective in the nODH of alkanes (primarily propane). The proposed catalyst compositions provide high yields or conversions of alkanes to olefins (primarily propylene).

[0029] Therefore, in a third aspect, the present invention relates to a method for preparing one or more (C2-C4)-olefins and / or one or more (C6)-aromatic compounds, the method comprising non-oxidative dehydrogenation of (C2-C4)-alkanes and / or (C3-C4)-olefins or, for the preparation of said one or more (C6)-aromatic compounds, non-oxidative dehydrogenation of (C2-C4)-alkanes and / or (C6)-cycloalkanes, said dehydrogenation being carried out by contacting a feed stream comprising said (C2-C4)-alkanes and / or (C3-C4)-olefins or said (C2-C4)-alkanes and / or (C6)-cycloalkanes with a catalyst composition defined in the first aspect to obtain said one or more olefins and one or more aromatic compounds.

[0030] The third aspect includes a method for preparing one or more (C2-C4)-olefins via non-oxidative dehydrogenation of (C2-C4)-alkanes or (C3-C4)-olefins that have been further dehydrogenated, and also includes a method for preparing one or more (C6)-aromatic compounds derived from the non-oxidative dehydrogenation of (C2-C4)-alkanes and from the non-oxidative dehydrogenation of (C6)-cycloalkanes if the (C6)-cycloalkanes are present in the feed stream composition in contact with the catalyst. For example, benzene can be produced from two molecules of propane (C3H8), which is dehydrogenated and condensed to give one molecule of benzene (C6H6) and five hydrogen (H2) molecules; or from one molecule of cyclohexane (C6H6)... 12 The cyclohexane is dehydrogenated to produce one molecule of benzene (C6H6) and three hydrogen (H2) molecules.

[0031] Another aspect of the invention is the use of the catalyst composition defined in the first aspect in the non-oxidative dehydrogenation of alkanes. That is, the use of the catalyst composition as defined above in the first aspect in non-oxidative propane dehydrogenation (PDH), non-oxidative butane-butene dehydrogenation (BDH), and propane aromatization. Attached Figure Description

[0032] Figure 1 Transmission electron microscopy (TEM) images of Pt-NPs prepared in THF (solvent, not an organic stabilizer) via an organometallic method or stabilized by PPh3 and NHC-CO2 are shown. Dimension reference: 20 nm.

[0033] Figure 2 TEM images of Pt-NPs (Pt (wt%): a)1, b)2, c)3, d)4, e)5) stabilized with NHC-CO2 and the support Na-ZSM5(5f) are shown. Dimension reference value: 100 nm.

[0034] Figure 3 TEM images of PtSn-NPs (Pt10 and Pt11) containing PPh3 (a) and without stabilizers (b).

[0035] Figure 4 The diagram illustrates a one-pot organometallic synthesis using the PtSn-L-NP@ support. L represents the ligand, which signifies an organic stabilizer.

[0036] Figure 5 High-resolution transmission electron microscopy (HRTEM) images of Pt6c(Al2O3), Pt7c(Li-Al2O3), Pt8c(Na-ZSM5), and Pt9c(H-ZSM5) in a Pt 2 wt%–Sn 1 wt% molar ratio (Pt / Sn 1:1). Size reference: 20 nm.

[0037] Figure 6 The diagram illustrates the mechanism of the proposed Sn and Pt precursors' decomposition on the support.

[0038] Figure 7 This illustrates the percentage (%) of propane conversion and the percentage (%) of propylene selectivity in nODH (PDH) of propane, comparing the results with and without poisoning in the feed stream, using toxic molecules, CO2, or no poisoning. Hollow circles show the change in reaction results over time (X-axis, in hours) in the presence of poisoning. Solid circles show the results without poisoning. Detailed Implementation Plan

[0039] Unless otherwise stated, all terms used in this application should be understood in their commonly known meaning in the art. Further, more specific definitions of certain terms used in this application are set forth below and are intended to apply uniformly throughout this specification and claims, unless otherwise expressly stated, which provides for a broader definition.

[0040] As used herein, the indefinite article “a” (and “an”) is synonymous with “at least one” or “one or more”. Unless otherwise stated, the definite article used herein, such as “the”, also includes the plural form of the noun.

[0041] As used herein, the term "nanoparticle" (and abbreviated as NP for abbreviation purposes) generally refers to a particle having at least two dimensions at the nanoscale, and particularly all three dimensions at the nanoscale (1-100 nm). In this specification, nanoparticles range from about 1.0 nm to about 15.0 nm. More specifically, they range from 1.0 nm to about 5.0 nm, and even more specifically, from 1.0 to 3.0 nm. Regarding the shape of the nanoparticles described herein, spherical and polyhedral shapes are included. In a particular embodiment, the nanoparticle is spherical.

[0042] As used herein, the term "size" refers to a characteristic physical dimension. For example, in the case of substantially spherical nanoparticles, the size of the nanoparticle corresponds to its diameter. When referring to a set of nanoparticles as having a specific size, it is envisioned that the set of nanoparticles may have a size distribution around the specified size. Therefore, the size of a set of nanoparticles as used herein may refer to a pattern of size distribution, such as the peak size of the size distribution. Furthermore, when not perfectly spherical, the diameter is the equivalent diameter of a sphere including the object.

[0043] When the diameter / size of nanoparticles is mentioned in this specification, it refers to the particle size measured by transmission electron microscopy (TEM). The size is also confirmed (verified) by X-ray diffraction (XRD).

[0044] As used herein, the term "catalyst composition" is understood to mean a composition consisting of a catalyst (active phase) and any other suitable component, such as a catalyst support. The catalyst compositions of the present invention are suitable for, for example, the non-oxidative dehydrogenation of alkanes, and particularly for, for example, the non-oxidative dehydrogenation of propane. Also in this specification, for abbreviation purposes, the catalyst composition is also referred to as M-NP, where M is one or more metals (Pt, Pd, Ni, Sn, Ga, In), and NP represents nanoparticles. The catalyst composition may also be referred to as M-NP@support, where @support represents a specific porous (e.g., mesoporous) support for adsorbing metal nanoparticles.

[0045] Throughout this specification and claims, the term (C2-C4)-olefin should be interpreted as straight-chain or branched, and covers propylene, ethylene, and butene (but-1-ene, (2Z)-but-2-ene, (2E)-but-2-ene, 2-methylprop-1-ene). The term (C2-C4)-alkane should be interpreted as straight-chain or branched, and in certain embodiments covers ethane, propane, and butane (n-butane and isobutane). The term aromatic (C6)-compound should be interpreted as benzene optionally substituted with a (C1-C4)-alkyl or -OR1 group, wherein R1 is selected from hydrogen (H) and (C1-C4)-alkyl, and covers benzene, toluene, o-xylene, m-xylene, and p-xylene. The term (C6)-cycloalkane compound refers to cyclohexane optionally substituted with a (C1-C4)-alkyl or -OR1 group, where R1 is selected from hydrogen (H) and (C1-C4)-alkyl, and covers cyclohexane, methylcyclohexane, or o-dimethylcyclohexane, m-dimethylcyclohexane, and p-dimethylcyclohexane. The (C1-C4)-alkyl group is methyl, ethyl, propyl, and butyl (n-butyl, isopropyl).

[0046] As described above, this invention relates to catalyst compositions comprising:

[0047] (a) Metal nanoparticles; and

[0048] (b) A porous carrier having a surface region; wherein the nanoparticles (a) are adsorbed on the surface region of the porous carrier;

[0049] The nanoparticles (a) comprise: (i) one or more metal elements of Group 10 of the periodic table; (ii) one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; and (iii) one or more metal elements selected from tin (Sn), gallium (Ga) and indium (In).

[0050] The one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides are also referred to herein as "nano-preparation control agents," "organic ligands," or "organic stabilizers." These are organic compounds that are adsorbed in a certain way onto one or more metal atoms that form part of the nanoparticles, such that during or after the preparation of the catalyst composition, the one or more elemental atoms neither aggregate with nor agglomerate with other surrounding nanoparticles (which also include the elemental atoms and the organic molecules selected from organophosphorus compounds and N-heterocyclic carbides). Therefore, these organic compounds act as nano-preparation control agents in the nanoparticles to prevent aggregation or agglomeration with other nanoparticles. This ensures that the nanoparticles are small and well dispersed in a predetermined volume or area. Furthermore, the inventors have observed that the presence of these organic molecules controls the final composition of the nanoparticles (i.e., the average diameter and size distribution of the nanoparticles, shape and crystallinity (alloys and core-shells), good distribution on the support, uniform composition in different regions of the support, and improved catalyst performance by controlling the reactivity of the nanoparticle sites).

[0051] For catalytic systems different from those of the present invention and for different reactions, the presence of certain organic molecules (i.e., nanomanufacturing controllers) in nanoparticles has been previously disclosed; for example, the hydrogenation of alkynes to obtain alkenes, which is carried out at temperatures of around 60°C, much lower than the dehydrogenation of alkane (typically around 100°C). See, for example, catalysts containing nickel (Ni), copper (Cu), and palladium (Pd) or combinations thereof (Ni-Cu, Pd-Cu) nanoparticles stabilized by C-coordinated N-heterocyclic carbides (NHC; or 1,3-dimethylimidazolium carbides) and obtained in a one-pot process via the decomposition of metal precursors (see Lomelí-Rosales et al., 2019, A general one-pot methodology for the preparation of monoand bimetallic nanoparticles supported on carbon nanotubes: application in thesemi-hydrogenation of alkynes and acetylene), Chem. Eur. J. 10.1002 / chem. 201901041).

[0052] However, it is generally accepted in the field of catalysts that each catalyst is suited to a specific reaction, and catalyst exchange between various reactions is usually meaningless because it is ineffective. Furthermore, optimization for one catalyst may not work for other catalysts that can be used to catalyze very different reactions.

[0053] The term "organophosphorus compound," also referred to as "P-coordination compound" in this specification, refers to an organic compound containing phosphorus (P). An example of an organophosphorus compound is phosphine. Phosphine (or phosphane) originates from the substitution of one or more hydrogen centers in the PH3 molecule by an organic substituent R (alkyl, aryl), yielding PH3. 3-x R x (Or PR1R2R3 if all H atoms are substituted) — an organophosphine, commonly referred to as phosphine, which can be primary, secondary, or tertiary phosphine depending on the number of hydrogen atoms substituted. In this invention, a specific and exemplary organophosphine is triphenylphosphine (PPh3). The general formula for phosphine is described below.

[0054]

[0055] In a specific embodiment of the catalyst composition according to the first aspect, the organophosphorus compound is a compound of formula (I):

[0056]

[0057] Where n is an integer of 0 or 1, and when n is 1, Z is oxygen (= O); and R1, R2, and R3 are each independently selected from:

[0058] -(C1-C 10 (C1-C4)-alkyl, particularly (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl, and (C1-C4)-alkanoyloxy, are all considered to be straight-chain or branched.

[0059] -Optionally substituted phenyl groups, especially those substituted with (C1-C4)-alkyl and / or -OH groups;

[0060] - A group represented by -CP(R4)(R5), wherein R4 and R5 are independently selected from hydrogen (H), phenyl and optionally substituted phenyl groups;

[0061] - A group represented by -N(R6)(R7), where R6 and R7 are independently selected from (C1-C2). 10(C1-C4)-alkyl, particularly (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl, and (C1-C4)-alkanoyloxy, are all considered to be straight-chain or branched; and

[0062] -Group-O-R8, wherein R8 is an optionally substituted C6-aromatic ring.

[0063] When n is 0 in formula (I), those skilled in the art understand that Z does not exist, and the organophosphorus compound of formula (I) has a pair of free electrons of phosphorus (P) atom.

[0064] When at least one of R1 to R3 in formula (I) is a group represented by -N(R6)(R7), the resulting organophosphorus compound is in fact a phosphonium amide. A specific example of a phosphonium amide is tris(dimethylamino)phosphine.

[0065] In another particular embodiment, the organophosphorus compound is selected from the phosphines disclosed above, and includes oxidized phosphine (i.e., including -P=O groups) and phosphorous amides (i.e., including at least one -N(R6)(R7) group) and phosphites / salts.

[0066] Phosphite esters / salts should be understood as salts of phosphorous acid, or uncharged phosphites containing or derived from the trivalent negative group PO3. Hydrogen phosphite is an ion. Its chemical formula is HPO3. 2- It contains phosphorus in the +3 oxidation state. The ester is a compound of the following formula, wherein Rx, Rx', and Rx" are the same or different groups, for example (C1-C2). 10 Alkyl or C6-aromatic rings (e.g., phenyl):

[0067]

[0068] In another specific embodiment of the catalyst composition of the present invention, the organophosphorus compound is a compound of formula (I), which is phosphine, wherein n is an integer of 0 or 1, and when n is 1, Z is oxygen (=O); and wherein R1, R2 and R3 are each independently selected from:

[0069] -(C1-C 10 (C1-C4)-alkyl, particularly (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl, and (C1-C4)-alkanoyloxy, are all considered to be straight-chain or branched.

[0070] -Optionally substituted phenyl groups, especially those substituted with (C1-C4)-alkyl and / or -OH groups;

[0071] - A group represented by -CP(R4)(R5), wherein R4 and R5 are independently selected from hydrogen (H), phenyl, and optionally substituted phenyl groups, and

[0072] - A group represented by -N(R6)(R7), where R6 and R7 are independently selected from (C1-C2). 10 (C1-C4)-alkyl, especially (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl and (C1-C4)-alkanoyloxy, are all considered to be straight-chain or branched.

[0073] In a more specific embodiment, the phosphine is selected from triphenylphosphine, 1,2-bis(diphenylphosphine)methane, tris(dimethylamino)phosphine, diphenylphosphine oxide, and trioctylphosphine oxide, and combinations thereof.

[0074] In an optional and another specific embodiment of the catalyst composition according to the invention, the organophosphorus compound is a compound of formula (I), which is a phosphite wherein n is 0, and wherein R1, R2 and R3 are each a group -O-R8, wherein R8 is an optionally substituted C6-aromatic ring, particularly substituted with a specific (C1-C4)-alkyl group.

[0075] In even more specific embodiments, the compound of formula (I) is triphenyl phosphite.

[0076] Therefore, in other words, in a specific embodiment of the catalyst composition of the first aspect, the organic molecule is selected from N-heterocyclic carbenes and organophosphorus compounds selected from phosphites and phosphine, wherein the phosphine includes oxidized phosphine and phosphorus amide. Specifically, the organophosphorus compound is selected from triphenylphosphine, 1,2-bis(diphenylphosphine)methane, tris(dimethylamino)phosphine, diphenylphosphine oxide and trioctylphosphine oxide, triphenyl phosphite and combinations thereof. The chemical formulas listed above, including phosphine and phosphites, are shown below:

[0077]

[0078]

[0079] The term "alkyl" includes (C1-C4)-alkyl, (C1-C4)-alkyl, and (C1-C4)-alkyl. 10 (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl, and (C1-C4)-alkanoyloxy are all considered to be straight-chain or branched. 10Examples of alkyl groups are methyl, ethyl, propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl. The term "aryl" refers to a group having a ring system of 1-3 rings, said rings being aromatic and being either isolated or partially / completely fused, and having 5-6 members, each independently selected from C, CH, N, NH, O, and S where chemically possible, and said ring system optionally substituted by one or more groups independently selected from (C1-C6)alkyl, (C1-C6)alkoxy, nitro, cyano, and halogen groups. Examples of aryl groups include phenyl and benzyl.

[0080] The “C-coordinated N-heterocyclic carbene” also referred to in this specification as “the carbon adduct of N-heterocyclic carbene” is a carbene of the formula RN2C:, where “R” is a (C2-C) atom that forms a heterocycle with two N atoms. n The N-heterocyclic carbide is an alkyl group, and the C atom is coordinated (i.e., added) to another carbon-containing compound (i.e., carbon dioxide). The carbon dioxide adduct of the N-heterocyclic carbide reacts under reaction conditions used for catalyst preparation to form an N-heterocyclic carbide (RN2C:) and another carbon-containing compound (i.e., carbon dioxide). In this invention, a specific and exemplary carbon adduct of the N-heterocyclic carbide is a 1,3-dimethylimidazolium carbide or ester (NHC-CO2) as shown below, which yields 1,3-dimethylimidazolium carbide.

[0081]

[0082] The Group 10 metals are nickel (Ni), palladium (Pd), and platinum (Pt). These elements are atoms that catalyze the reaction. In a specific embodiment of the catalyst composition, the nanoparticles (a) contain at least platinum (Pt) or nickel (Ni). In another specific embodiment of the first aspect, the nanoparticles contain Pt and / or a combination of Ni and Pd.

[0083] The one or more metal elements selected from tin (Sn), gallium (Ga), and indium (In) are co-catalysts in the catalyst composition. Therefore, they also increase the rate of chemical reactions catalyzed by the Group 10 metal elements in the nanoparticles and synergistically enhance each other's catalytic activity (better yield and / or selectivity).

[0084] In a specific embodiment of the first aspect, optionally combined with any of the above or below embodiments, one or more of tin (Sn), gallium (Ga), and indium (In) are in the nanoparticles (a) and on the surface region of the porous support (b). Indeed, any of these co-catalysts, particularly those closely attached to the nanoparticles (a), are primarily adsorbed on the surface region of the primary nanoparticles (a') that is only closely attached to the one or more Group 10 metal elements, and they are also on the surface region of the porous support (b). Therefore, the catalyst composition comprises:

[0085] (a) Nanoparticles comprising the aforementioned Group 10 metal element, one or more cocatalysts, and one or more organic molecules selected from organophosphorus compounds and N-heterocyclic compounds; and

[0086] (b) A porous support comprising nanoparticles adsorbed on its surface and one or more cocatalysts independent of the nanoparticles (i.e. not forming part of the nanoparticles).

[0087] In yet another specific embodiment, the nanoparticles of the catalyst composition contain two or three elements selected from Sn, Ga, and In (i.e., co-catalysts).

[0088] In another specific embodiment of the catalyst composition of the first aspect, which is optionally combined with the above or other embodiments, the composition further comprises one or more co-catalysts, specifically alkali metal elements, more specifically selected from lithium (Li) and sodium (Na).

[0089] A catalyst promoter is a substance or element added to a solid catalyst composition to improve its performance in a chemical reaction. Catalyst promoters enhance the action (efficiency) of the catalyst, but they do not possess any catalytic activity.

[0090] The nanoparticles in the catalyst composition have diameters of less than 1.0 nm to 15 nm, particularly 0.5 nm to 15 nm, and more particularly 1.0 to 15.0 nm (e.g., 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, and 15.0). Nanoparticles containing Ni as the sole Group 10 element, as well as Sn and / or Ga, have diameters of 10.0 nm to 15.0 nm.

[0091] The Pt-containing nanoparticles have a diameter ranging from 1.0 nm to 5.0 nm. Generally, smaller nanoparticle sizes lead to better catalyst performance because the dispersion of the number of available active metal sites is maximized. This results in more efficient utilization of the precious metal. Thus, in another specific embodiment of the catalyst according to the first aspect, the nanoparticles have a diameter of 1.0-5.0 nm, including diameters of 1.0, 2.0, 3.0, 4.0, and 5.0 nm, more particularly 1.0 to 3.0 nm, including diameters of 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, and 3.0 nm, and even more particularly a diameter of 1.0 to 2.0 nm. As will be illustrated in the examples below, the diameter of all these nanoparticles refers to the diameter determined by TEM.

[0092] In another specific embodiment, the catalyst composition according to the first aspect has a concentration of 100 to 500 m. 2 / g of specific surface area according to BET theory (in m²) 2 / g (calculated).

[0093] The BET surface area used in this paper was determined by nitrogen (N2) adsorption technology (ASTM D-3663-03, ASTM International, October 2003; or ISO 9277, standard for calculating the specific surface area of ​​solids based on the BET method). The Brunauer-Emmett-Teller (BET) theory aims to explain the physical adsorption of gas molecules on solid surfaces and serves as the basis for an important analytical technique for measuring the specific surface area of ​​materials. In the field of solid-state catalysis, the surface area of ​​a catalyst is a crucial factor in its catalytic activity.

[0094] In another specific embodiment, in the catalyst composition according to the first aspect, the molar ratio of the one or more organic molecules to one or more total metal elements is 0.05-0.25:1. The molar ratio is determined by, for example, X-ray photoelectron spectroscopy, which measures the bands corresponding to P, N, or C associated with the metal bands. Typically, each nanoparticle contains 30-40 metal atoms, and the nanoparticle contains 5-10 organic molecules that act as stabilizers for the nanoparticle.

[0095] Another specific embodiment of the catalyst composition, optionally combined with any of the above or below catalyst composition embodiments, is that the porous support is selected from porous supports based on alumina, silica, mesoporous zeolites, and related aluminosilicates. According to IUPAC definitions, solids containing pores with a pore size (i) > 50 nm are called macroporous, solids containing pores with a pore size (ii) 1-50 nm are called mesoporous, and solids containing pores with a pore size (iii) < 1 nm are called microporous. In a specific embodiment of the catalyst composition optionally combined with any of the above or below embodiments, the support is a mesoporous support.

[0096] The term "alumina-based" means that the porous support primarily comprises or is composed of alumina (Al₂O₃). Similarly, "silica-based" means that the mesoporous support primarily comprises or is composed of silica (SiO₂). Likewise, the expression "zeolite- and related aluminosilicates" means that the porous support primarily comprises or is composed of aluminosilicates of several chemical formulas.

[0097] In selecting alumina, it is specifically chosen from γ-Al₂O₃ and θ-Al₂O₃, as well as alumina catalyzed by alkali metal elements (Li-Al₂O₃ and Na-Al₂O₃). Methods for preparing these alumina supports are disclosed, for example, in the following study: Rouge et al., (2019), A smarter approach to catalysts by design: Combining surface organometallic chemistry on oxide and metal gives selective catalysts for dehydrogenation of 2,3-dimethylbuthane, Molecular Catalysis 471, 21-26. (See the Examples section for more details).

[0098] In more specific embodiments, zeolite-type materials (particularly ZSM-5 zeolite) are materials with no or only a few acidic sites, which have been selected for targeting propane dehydrogenation (PDH) and butane dehydrogenation (BDH) reactions, while zeolites with a large number of acidic sites have been selected for targeting aromatization reactions. Methods for preparing these zeolite supports are disclosed, for example, et al., (2008), Methanol to gasoline over zeolite H-ZSM-5: Improved catalyst performance by treatment with NaOH, Applied Catalysis A: General 345, 43-50.

[0099] The nanoparticles in the catalyst composition are uniformly distributed across the entire surface of the porous support. In a particular embodiment, the support exhibits a pore size in the mesopore range of 1 nm to 50 nm. In a particular embodiment, the support exhibits a pore size in the micropore range of approximately 1 nm.

[0100] In another specific embodiment of the catalyst composition of the first aspect, the weight percentage of the one or more Group 10 metal elements is 0.2 to 5.0%, more particularly 0.2 to 2.5%, or even more particularly 0.2 to 2.0%, and the weight percentage of the one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides is 0.05 to 0.2%, wherein all percentages are relative to the total weight of the catalyst composition, and therefore relative to the total weight of the catalyst composition comprising metal nanoparticles and porous supports, co-catalysts and optional co-catalysts (if present).

[0101] In a more specific embodiment, the weight percentage of the one or more Group 10 elements is from 0.5 wt% to 2.5 wt% relative to the total weight of the catalyst composition, more particularly from 1.0 wt% to 2.5 wt%, including 1.0, 1.5, 2.0 and 2.5 wt%.

[0102] When the terms "% by weight," "w / w," or "weight percentage" are indicated in this specification, they refer to the amount of a single component relative to the total weight of the composition or, if specifically mentioned, the other components. For example, 1% by weight of Pt means 1% by weight of platinum in the final catalyst composition. When the catalyst composition contains two or more of platinum (Pt), nickel (Ni), and palladium (Pd), the above weight percentage corresponds to a percentage of each element or the sum of the elements.

[0103] As described above, the catalyst composition comprises tin (Sn), gallium (Ga), indium (In), and combinations thereof. In a more specific embodiment, the one or more metal elements are selected from Sn, Ga, and In, and the weight percentage is 0.15 to 1.0% relative to the total weight of the catalyst composition. In another specific embodiment, the catalyst composition comprises 0.8 to 2.0% by weight of one or more co-catalysts, particularly selected from lithium (Li), sodium (Na), and combinations thereof, all percentages relative to the total weight of the catalyst composition. As previously stated, when the catalyst composition comprises two or more of Sn, Ga, and In as a co-catalyst or Li and Na as a co-catalyst, the aforementioned weight percentages correspond to the percentage of each element (e.g., Sn) or the sum of all elements (e.g., Sn and Ga in a Pt / Ga_NP@ support).

[0104] In another specific embodiment of the first aspect, the catalyst composition comprises:

[0105] (a) Metal nanoparticles; and

[0106] (b) A porous carrier having a surface region, wherein the nanoparticles (a) are adsorbed on the surface region of the porous carrier;

[0107] The nanoparticles (a) comprise: (i) 0.2 to 5.0% by weight of one or more metals from Group 10 of the periodic table; (ii) 0.05 to 0.2% by weight of one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; and (iii) 0.15 to 1.0% by weight of one or more metals selected from Sn, Ga, and In, all percentages relative to the total weight of the catalyst composition; and

[0108] The porous support (b) contains 0.8 to 2.0% by weight of one or more co-catalysts such as Li and / or Na, the percentage being relative to the total weight of the catalyst composition.

[0109] Furthermore, in another more specific embodiment of the catalyst composition of the first aspect, optionally combined with embodiments of the above or any of the compositions described below, it comprises:

[0110] (a) Metal nanoparticles; and

[0111] (b) A porous carrier having a surface region, wherein the nanoparticles (a) are adsorbed on the surface region of the porous carrier;

[0112] The nanoparticles (a) comprise: (i) one or more metallic elements selected from Group 10 of the periodic table, such as platinum (Pt) and nickel (Ni); (ii) one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; and (iii) one or more metallic elements selected from tin (Sn) and gallium (Ga).

[0113] In another specific embodiment of the catalyst composition, the nanoparticles are multimetallic nanoparticles comprising Group 10 atoms, particularly Ni and / or Pt and optionally Pd atoms, and Sn, Ga, In atoms and combinations thereof as co-catalysts, or consisting of these atoms; the nanoparticles are stabilized with an organophosphorus compound (i.e., a P-coordination compound) such as phosphine. Specific phosphine includes PPh3.

[0114] In a particular embodiment of the first aspect, optionally combined with embodiments of any of the compositions described above or below, the nanoparticles comprise Pt as the sole Group 10 element and PPh3 as an organic stabilizer (i.e., a specific example of an organophosphorus compound), and it further comprises one or more elements selected from Sn, Ga, and In.

[0115] In another specific embodiment of the catalyst composition, the nanoparticles are bimetallic or bielemental nanoparticles comprising, or composed of, Group 10 atoms, particularly Ni or Pt atoms and one of Sn, Ga, and In atoms (i.e., co-catalysts), or consisting of Group 10 atoms, particularly Ni or Pt atoms and one of Sn, Ga, and In atoms (i.e., co-catalysts). The bimetallic nanoparticles are stabilized with an organophosphorus compound (i.e., a P-coordination compound) such as phosphine, more particularly PPh3. In a more specific embodiment, the bimetallic nanoparticles comprise Pt atoms and Sn atoms, as well as an organophosphorus compound as an organic stabilizer.

[0116] In another specific embodiment of this catalyst composition having bimetallic nanoparticles, the catalyst composition further comprises one or more co-catalyst atoms of Sn, Ga, and In adsorbed on the surface region of a selected porous support. In yet another more specific embodiment, the total catalyst contains Pt in the range of 1.0 to 2.0 wt%, and Sn in the total catalyst (both in the nanoparticles and adsorbed on the support) in the range of 0.2 to 0.7 wt%. In yet another more specific embodiment, the total catalyst contains Pt in the range of 1.0 to 2.0 wt%, and Ga in the total catalyst (both in the nanoparticles and adsorbed on the support) in the range of 0.2 to 0.7 wt%. In yet another more specific embodiment, the total catalyst contains Pt in the range of 1.0 to 2.0 wt%, and In in the total catalyst (both in the nanoparticles and adsorbed on the support) in the range of 0.2 to 0.7 wt%. In yet another more specific embodiment of the catalyst composition having at least bimetallic nanoparticles, the total catalyst contains Ni in the range of 1.0 to 2.0% by weight, and Sn in the total catalyst (in the nanoparticles and adsorbed on the support) in the range of 0.2 to 0.7% by weight.

[0117] In another specific embodiment of the catalyst composition, it comprises trimetallic nanoparticles. In a more specific embodiment, the trimetallic nanoparticles comprise Pt, Ni, and Sn. In such a more specific embodiment of the catalyst composition having trimetallic nanoparticles, the weight percentage of Ni and Pt in the total catalyst is in the range of 1.0 to 2.0 wt%, and the weight percentage of Sn in the total catalyst (in the nanoparticles and adsorbed on the support) is 0.2 to 0.7 wt%.

[0118] The specific combinations of the metal in the nanoparticles with several mesoporous carriers as previously disclosed are illustrated in the examples below.

[0119] This specification also discloses catalyst compositions having single-metal nanoparticles adsorbed on a porous support (along the surface region). Specifically, the nanoparticles are metal nanoparticles containing only platinum (Pt) atoms and an organophosphorus compound (i.e., a P-coordination compound) such as phosphine, particularly PPh3. In another, more specific embodiment of such a catalyst containing single-metal nanoparticles, the total catalyst contains 1.0% to 5.0% by weight of Pt.

[0120] Another aspect of the invention is a method for preparing the catalyst composition defined in the first aspect, the method comprising, in a one-pot step, decomposing one or more organometallic precursor compounds of one or more Group 10 elements and one or more organometallic precursor compounds of one or more metal elements selected from tin (Sn), gallium (Ga), and indium (In) in the presence of an organic solvent, a porous support, and one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; said one-pot decomposition is carried out in a hydrogen atmosphere at a temperature of 20°C to 100°C and 1.0 x 10⁻⁶ ppm. 5 Pa up to 5.0 x 10 5 Perform tests under Pa pressure for 30 minutes to 70 hours.

[0121] If the catalyst composition must contain a co-catalyst, particularly one selected from Li and Na, these elements are added to the reaction mixture, or they are provided with a porous support by reacting the porous support with an alkali metal base (i.e., sodium hydroxide (NaOH) for zeolites or an organometallic lithium reagent for alumina) (see [link to relevant documentation]). (See et al. (2008) and Rouge et al. (2019), ibid.)

[0122] In a specific embodiment of the preparation method, the one or more organometallic precursor compounds are added in an amount of 1 mole of Group 10 atoms per 0.1 to 1.0 mole of one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbenes (i.e., organic nanofabrication controllers).

[0123] Therefore, the initial ratio of organic nano-preparing agents (i.e., organic ligands or organic stabilizers) in the nanoparticle formulation is 0.1-1.0 moles per mole of Group 10 metal, and the final ratio of organic nano-preparing agents in the nanoparticles separated in the catalyst (i.e., in the nanocatalyst composition) depends on the variation of the nano-preparing agents in the ratio of 0.1-1.0 moles per mole of Group 10 metal.

[0124] In yet another specific embodiment of the method according to the second aspect, the organometallic precursor compound is selected from bis(diphenylmethylacetone) and tri(diphenylmethylacetone) of Group 10 metals, 1,5-cyclooctadiene dimethyl of Group 10 metals, (C1-C4)-alkyl complexes of cocatalyst elements Sn, Ga, and In, and combinations of all these organometallic precursors. In a more specific embodiment, the organometallic precursor compound is selected from tri(diphenylmethylacetone)platinum (abbreviated as Pt2(dba)3), 1,5-cyclooctadiene dimethylplatinum (abbreviated as Pt2(dba)3), and 1,5-cyclooctadiene dimethylplatinum (abbreviated as Pt2(dba)3). (II) (COD)Me2), dicyclooctadiene nickel (abbreviated as Ni) (0) (COD)2), Tetrabutyltin (abbreviated as Sn)(IV) Bu4), tetramethyltin (abbreviated as Sn) (IV) Me4), tributyltin hydride (abbreviated as HSn) (IV) Bu3), hexabutyltin (abbreviated as Sn2) (III) Bu6), hexamethyltin (abbreviated as Sn2) (III) Me6), N,N'-di-tert-butyl-2,3-diamidotin (abbreviated as Sn) (II) C 12 H 26 N2) trimethylgallium (abbreviated as GaMe3) and cyclopentadienyl indium (abbreviated as InCp).

[0125] In another specific embodiment of the preparation method, optionally combined with any of the above or below method embodiments, the organic solvent is selected from ether-containing solvents (especially tetrahydrofuran, methyltetrahydrofuran, dioxane and diethyl ether), aromatic solvents (especially benzene, toluene, anisole, methyl anisole and xylene), and alkanes (especially cyclohexane, hexane, pentane) and mixtures thereof.

[0126] In another specific embodiment of the preparation method, optionally combined with any of the above or below method embodiments, the organophosphorus compound is a compound of formula (I) as defined in the first aspect of the invention and its corresponding embodiments. Therefore, the method is specifically carried out using an organophosphorus compound of formula (I) selected from phosphites or esters and phosphine, wherein the phosphine includes oxidized phosphine and phosphine amides. Specifically, the organophosphorus compound used to carry out the method is selected from triphenylphosphine, 1,2-bis(diphenylphosphine)methane, tris(dimethylamino)phosphine, diphenylphosphine oxide and trioctylphosphine oxide, triphenyl phosphite, and combinations thereof.

[0127] In a particular embodiment, the catalyst preparation method is carried out in a hydrogen atmosphere at room temperature (20°C to 35°C) and 2.0 x 10⁻⁶ ppm. 5 Pa to 4.0 x 10 5 The test was conducted at a pressure of Pa. More specifically, it was performed in a hydrogen atmosphere at room temperature and 3.0 x 10⁻⁶ Pa. 5 The process is carried out under a pressure of Pa. Hydrogen gas provides a reducing environment, which, as will be described below, initiates the reduction of the organometallic compound to obtain a metal that adheres closely to the nanoparticles and / or is deposited on the surface of a selected support.

[0128] In an alternative embodiment, the catalyst is prepared in a hydrogen atmosphere at a temperature of 90°C to 100°C and 2.0 x 10⁻⁶ ppm. 5 Pa to 4.0 x 10 5 The test was conducted at a pressure of Pa. More specifically, it was performed in a hydrogen atmosphere at 100°C and 3.0 x 10⁻⁶ Pa.5 The test was conducted under a pressure of Pa.

[0129] As described above, in certain embodiments, the catalyst composition can also be defined by the preparation method of the second aspect. Therefore, all specific embodiments of the second aspect are applicable to the catalyst compositions that can be obtained therefrom.

[0130] Therefore, the present invention also includes a catalyst composition comprising:

[0131] (a) Metal nanoparticles; and

[0132] (b) A porous carrier having a surface region; wherein the nanoparticles (a) are adsorbed on the surface region of the porous carrier;

[0133] The nanoparticles (a) therein comprise: (i) one or more metal elements of Group 10 of the periodic table; (ii) one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; and (iii) one or more metal elements selected from tin (Sn), gallium (Ga) and indium (In);

[0134] The catalyst composition can be obtained as follows: in a one-pot process, in the presence of an organic solvent, a porous support, and one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides, one or more organometallic precursor compounds of one or more Group 10 elements and one or more organometallic precursor compounds of one or more metal elements selected from tin (Sn), gallium (Ga), and indium (In) are decomposed; the one-pot decomposition is carried out in a hydrogen atmosphere at a temperature of 20°C to 100°C and 1.0 x 10⁻⁶ ppm. 5 Pa to 5.0 x 10 5 Perform tests under Pa pressure for 30 minutes to 70 hours.

[0135] As previously stated, the one-pot synthesis of the catalyst composition is highly advantageous because it is a simple, affordable, and reliable method for preparing the highly effective and selective catalysts of the present invention.

[0136] However, an alternative synthesis mode for the catalyst composition begins with a colloidal suspension containing metal nanoparticles as a suspended discrete phase in an organic solvent as a continuous phase. These colloidal suspensions are then deposited onto a porous support via an impregnation method.

[0137] The method for loading colloidal nanoparticles onto a support comprises two steps. In the first step, in a Fisher-Porter reactor, a desired organometallic precursor (containing one or more metal elements selected from tin (Sn), gallium (Ga), indium (In), platinum (Pt), or palladium (Pd)) is placed in the presence of one or more organic molecules (i.e., nanofabrication controllers) selected from organophosphorus compounds and N-heterocyclic carbides. The mixture is then subjected to a hydrogen atmosphere (particularly 1.0 x 10⁻⁶) in the presence of an organic solvent. 5 Pa to 5.0 x 10 5 The mixture was decomposed under pressure (Pa) and heated at 20°C to 100°C for 30 minutes to 70 hours. The remaining hydrogen pressure was then vented, and the colloidal nanoparticle dispersion was maintained under an inert atmosphere. In the second step, following an impregnation procedure, a determined volume of the colloidal nanoparticle dispersion was added via a conduit to a Schlenk flask containing the selected support (e.g., Al₂O₃ and ZSM-5) according to the desired metal percentage on the support, and the mixture was exposed to ultrasound to facilitate diffusion of the nanoparticles within the support pore system. The mixture was then stirred for 1 to 7 days. The resulting mixture was filtered and washed with anhydrous degassed hexane. The material was dried under vacuum and stored under an inert atmosphere.

[0138] This alternative approach involves two steps, but it remains affordable and less complex compared to methods used to obtain certain commercial catalysts currently used in the n-ODH field. Furthermore, another advantage of this approach is that the support can be selected according to the end-user's needs.

[0139] Therefore, the present invention also includes a colloidal suspension catalyst composition comprising metal nanoparticles (a) suspended in an organic solvent (b), wherein said nanoparticles (a) comprise: (i) one or more metal elements of Group 10 of the periodic table; (ii) one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; and (iii) one or more metal elements selected from tin (Sn), gallium (Ga) and indium (In).

[0140] These colloidal suspensions are specifically obtained by the following method: decomposing one or more organometallic precursor compounds of one or more Group 10 elements and one or more organometallic precursor compounds of one or more metal elements selected from tin (Sn), gallium (Ga), and indium (In) in an organic solvent and one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; the one-pot decomposition is carried out in a hydrogen atmosphere at a temperature of 20°C to 100°C and 1.0 x 10⁻⁶ m³ / h. 5 Pa to 5.0 x 10 5 Perform tests under Pa pressure for 30 minutes to 70 hours.

[0141] The nanoparticles in the catalyst composition of the first aspect of the present invention are also applicable to colloidal suspensions of these nanoparticles, which are specific embodiments of one or more of the Group 10 metals of the periodic table, Sn, Ga and In, or a combination of specific organic molecules selected from organophosphorus compounds and N-heterocyclic carbenes.

[0142] In certain embodiments, the organic solvents in these colloidal suspensions are selected from ether-containing solvents (especially tetrahydrofuran, methyl-tetrahydrofuran, dioxane and diethyl ether), aromatic solvents (especially benzene, toluene, anisole, methyl anisole and xylene), and alkanes (especially cyclohexane, hexane, pentane) and mixtures thereof.

[0143] Similarly, the specific organometallic precursor compounds and their initial and final molar ratios to organic molecules, specific temperature ranges, and times disclosed in the method for preparing the catalyst composition of the first aspect are also applicable to the preparation of these colloidal suspensions, which are also conceived as intermediates for obtaining the catalyst composition of the first aspect.

[0144] The present invention also relates to a method for producing one or more (C2-C4)-olefins and / or one or more (C6)-aromatic compounds, the method comprising non-oxidative dehydrogenation of (C2-C4)-alkanes and / or (C3-C4)-olefins or, for the production of one or more (C6)-aromatic compounds, non-oxidative dehydrogenation of (C2-C4)-alkanes and / or (C6)-cycloalkanes, wherein the dehydrogenation is carried out using the steps of contacting a feed stream comprising the (C2-C4)-alkanes and / or (C3-C4)-olefins or the (C2-C4)-alkanes and / or (C6)-cycloalkanes with a catalyst composition defined in the first aspect to obtain the one or more olefins and one or more aromatic compounds.

[0145] In a particular embodiment of a method for producing one or more (C2-C4)-olefins and / or one or more (C6)-aromatic compounds, the olefins are selected from ethylene, propylene, and butadiene, and the one or more aromatic compounds are selected from benzene, toluene, o-xylene, m-xylene, p-xylene, and mixtures thereof.

[0146] The term “non-oxidative dehydrogenation” is understood to mean dehydrogenation in the absence of oxidants such as oxygen or carbon dioxide, i.e., the amount of oxidant in the feed stream containing alkane is at most 1 vol based on the feed stream.

[0147] The examples below illustrate that when the catalyst of the present invention (first aspect) is used, propane is highly and selectively converted to propylene (without other side reactions). Therefore, in a specific embodiment of the method for obtaining (C2-C4)-olefins and / or (C6)-aromatic compounds from alkanes and (C6)-cycloalkanes, the alkane is propane, and the obtained olefin is propylene.

[0148] In another specific embodiment of the method for obtaining (C2-C4)-olefins in the third aspect, nODH of (C3-C4)-olefins as 2-butene (C4-olefin) is carried out to obtain butadiene (another more oxidized C4-olefin).

[0149] In yet another specific embodiment of the method for obtaining (C2-C4)-olefins, butadiene is obtained by nODH comprising a mixture of 2-butene (C4-olefin) and butane (C4-alkane).

[0150] In another specific embodiment of the method, the non-oxidative dehydrogenation is carried out at a temperature of 400 to 650°C. In yet another specific embodiment, it is carried out at a temperature of 500 to 600°C, including 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, and 600°C.

[0151] In another specific embodiment of the method, the non-oxidative dehydrogenation is carried out at a feed flow rate of 1.5 mL / min to 3.0 mL / min of (C2-C4)-alkanes and / or (C6)-aromatic compounds, and in a specific instance, it is carried out at a feed flow rate of 3.0 mL / min, the feed flow comprising (C2-C4)-alkanes, more particularly propane, or consisting thereof.

[0152] In another specific embodiment of the method, the non-oxidative dehydrogenation is carried out in the presence of an inert gas, which is applied, in particular, at a flow rate of 10.5 to 21 mL / min. In a specific embodiment, the inert gas is selected from argon (Ar) and nitrogen (N2). In a more specific embodiment, the gas is Ar, and its flow rate in the feed stream is 21 mL / min.

[0153] In another specific embodiment of the method, the non-oxidative dehydrogenation is carried out in the presence of hydrogen at a flow rate of 0 to 3.0 mL / min. In a more specific embodiment, the hydrogen flow rate is 0.1 to 3.0 mL / min. In yet another more specific embodiment, the hydrogen flow rate is 0 to 1.5 mL / min. These hydrogen streams provide 0 to 0.5 mol of hydrogen per mole of (C2-C4)-alkanes and / or (C6)-aromatic compounds.

[0154] In another specific embodiment of the method, the non-oxidative dehydrogenation is at 5.0 x 10⁻⁶. 4 Pa to 1.5 x 10 5 Under Pa pressure, in a specific implementation scheme, 1.0 x 10 5 It is carried out under a pressure of Pa (bar).

[0155] In yet another, more specific embodiment of the method of the third aspect, the non-oxidative dehydrogenation is carried out at a temperature of 400 to 650°C, comprising a feed flow rate of 0.1 mL / min to 3.0 mL / min of (C2-C4)-alkane (3.0 mL / min propane in a specific example), 10.5 to 21 mL / min of inert gas (21 mL / min argon (Ar) in a specific example), and 0 to 1.5 mL / min of hydrogen (0.5 mL / min hydrogen in a specific example); and the non-oxidative dehydrogenation is carried out at a temperature of 5.0 x 10⁻⁶ °C. 4 Pa to 1.5 x 10 5 Pa, in a specific implementation scheme, 1.0 x 10 5 The test was conducted at a pressure of Pa (1 bar).

[0156] In a more specific example of the method, it is performed at a temperature of 530°C and a feed flow rate comprising 3 mL / min of (C2-C4)-alkanes (particularly propane), 21 mL / min of argon, and 1 mL / min of hydrogen, and 1 bar (1 x 10⁻⁶). 5 It is carried out under a pressure of (Pa).

[0157] The inventors also recognize that the method for producing olefins and / or aromatic compounds can achieve even better performance and yield if it further includes a catalyst pretreatment step. In another specific embodiment of the method, it further includes a catalyst pretreatment comprising exposing the catalyst composition to a hydrogen flow rate of 10 to 20 mL / min for a period of 4 to 16 hours, while increasing the temperature from 20°C to 500°C-600°C at a rate of 1°C / min.

[0158] In another embodiment, the non-oxidative dehydrogenation is carried out in the presence of a poisoning molecule.

[0159] Finally, in yet another specific embodiment of the method for producing one or more (C2-C4)-olefins and / or one or more (C6)-aromatic compounds in the third aspect, the amount of the catalyst composition is 20 to 200 mg per unit total feed stream volume. These amounts of catalyst composition result in highly selective (selectivity greater than 99%) conversion of the propane feed and significantly higher conversion rates (23-25% at 530°C and 1 bar) and stability compared to conventional catalysts.

[0160] Therefore, in a specific example, the novel catalyst composition is suitable for a method of non-oxidative catalytic dehydrogenation of propane, the method comprising passing the feed to be dehydrogenated over a catalyst (i.e., the catalyst composition) containing 0.2 to 5.0%, particularly 0.2 to 2.0 wt%, of Group 10 elements (nickel, palladium, and platinum, and combinations thereof) (the Group 10 elements are in nanoparticles), 0.05 to 0.2 wt% of organic molecules (N-coordination compounds such as amines, P-coordination compounds such as phosphine, C-coordination N-heterocyclic carbides, and combinations thereof) as nano-manufacturing controllers (which are also in close proximity to the nanoparticles), the catalyst further containing 0.15 to 1.0 wt% of co-catalysts (tin, gallium, and indium, and combinations thereof), and 0.8 to 2 wt% of alkali metal elements (lithium and sodium) as co-catalysts, and the catalyst is used in a one-pot process, through the catalyst and co-catalyst organometallic precursors in the presence of the organic molecules (i.e., nano-manufacturing controllers) and a mesoporous support, in a hydrogen atmosphere (1.0 x 10⁻⁶). 5 Pa to 5.0 x 10 5 The dehydrogenation is obtained by controlled decomposition in a solution at a specific temperature (25 to 100 °C) and Pa. Dehydrogenation proceeds via the following sequence: pre-reduction of alkanes at a temperature between 450 and 550 °C in the presence of hydrogen, and dehydrogenation of alkanes at a temperature between 530 and 650 °C, 5.0 x 10⁻⁶ ppm. 4 Pa to 3.0 x 10 5 Pressure between Pa and total flow rate of 200 to 120,000 mL x gcat -1 xh -1 (2 to 14400 mL propane x gcat) -1 xh -1 Dehydrogenation at the gas spacetime velocity (GHSV) between )

[0161] This document also discloses catalyst compositions, which are defined as comprising:

[0162] (a) Metal nanoparticles; and

[0163] (b) A porous carrier having a surface region; wherein the nanoparticles (a) are adsorbed on the surface region of the porous carrier;

[0164] The nanoparticles (a) comprise: (i) one or more metals of Group 10 of the periodic table; and (ii) one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides, wherein at least one Group 10 element in the nanoparticles is platinum (Pt) or nickel (Ni), and wherein when the nanoparticles comprise Ni as the only Group 10 element, it further comprises tin (Sn) and / or gallium (Ga), and when the nanoparticles comprise Pt as the only Group 10 element, the molar ratio of the one or more organic molecules to the one or more Group 10 metals is 0.05-0.25:1.

[0165] A method for preparing a catalyst composition as defined in the preceding paragraph is also disclosed, the method comprising, in a one-pot step, decomposing one or more organometallic precursor compounds of one or more Group 10 elements, i.e., organometallic precursor compounds containing platinum and / or nickel, in the presence of an organic solvent, a porous support, and one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; said one-pot decomposition is carried out in a hydrogen atmosphere at a temperature of 20°C to 100°C and 1.0 x 10⁻⁶ ppm. 5 Pa to 5.0 x 10 5 The reaction is carried out at a pressure of Pa for 30 minutes to 70 hours; and wherein when the catalyst composition contains nanoparticles containing nickel as the sole Group 10 element, the one or more organometallic precursor compounds contain tin and / or gallium; and when the catalyst composition contains platinum as the sole Group 10 element, the molar ratio of Pt to one or more organic molecules in the reaction will give a final molar ratio of organic molecules to Pt of 0.05-0.25:1.

[0166] Therefore, another part of the present invention is a catalyst composition comprising:

[0167] (a) Metal nanoparticles; and

[0168] (b) A porous carrier having a surface region; wherein the nanoparticles (a) are adsorbed onto the surface region of the mesoporous carrier;

[0169] The nanoparticles (a) comprise: (i) one or more metal elements of Group 10 of the periodic table; and (ii) one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides, wherein at least one element in the nanoparticles is platinum (Pt) and / or nickel (Ni), and wherein if the nanoparticles comprise Ni as the only Group 10 element, they also comprise tin (Sn) and / or gallium (Ga), and when the nanoparticles comprise Pt as the only Group 10 element, the molar ratio of the one or more organic molecules to the one or more Group 10 metal elements is 0.05-0.25:1;

[0170] The catalyst composition can be obtained as follows: in a one-pot step, in the presence of an organic solvent, a mesoporous support, and one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides, one or more organometallic precursor compounds of Group 10 elements, i.e., organometallic precursor compounds containing platinum (Pt) and / or nickel (Ni), are decomposed; the one-pot decomposition is carried out in a hydrogen atmosphere at a temperature of 20°C to 100°C and 1.0 x 10⁻⁶ ppm. 5 Pa up to 5.0 x 10 5 The reaction is carried out under a pressure of Pa for a period of 30 minutes to 70 hours; and wherein when the catalyst composition contains nanoparticles containing nickel as the only Group 10 element, the one or more organometallic precursor compounds contain tin (Sn) and / or gallium (Ga); and wherein when the catalyst composition contains nanoparticles containing platinum as the only Group 10 element, the molar ratio of Pt to one or more organic molecules in the reaction will give a final molar ratio of organic molecules to Pt of 0.05-0.25:1.

[0171] A method for preparing a catalyst composition is also disclosed, the catalyst comprising:

[0172] (a) Metal nanoparticles comprising one or more metals of Group 10 of the periodic table and one or more metals selected from tin (Sn), gallium (Ga), and indium (In); and

[0173] (b) A porous carrier having a surface region; wherein the nanoparticles (a) are adsorbed onto the surface region of the mesoporous carrier;

[0174] The method includes, in a one-pot step, the decomposition of one or more organometallic precursor compounds of one or more Group 10 elements in the presence of an organic solvent and a porous support, and the decomposition of one or more organometallic precursor compounds of one or more metal elements selected from tin (Sn), gallium (Ga), and indium (In); the one-pot decomposition is carried out in a hydrogen atmosphere at a temperature of 20°C to 100°C and 1.0 x 10⁻⁶ ppm. 5 Pa to 5.0 x 10 5 Perform tests under Pa pressure for 30 minutes to 70 hours.

[0175] As will be illustrated in the examples below, the method described in the preceding paragraph allows for the production of PtSn nanoparticles with an average diameter of 1.42 nm. The Pt content in the catalyst composition is 1.328 wt% (relative to the total weight of the catalyst composition and measured by ICP). The Sn content is 1.381 wt% (relative to the total weight of the catalyst composition and measured by ICP). The molar ratio of Pt to Sn is 1.71.

[0176] Therefore, in a specific instance of this method, the Group 10 element is Pt. In another specific instance, the metallic element is tin (Sn). In even more specific instances, the Group 10 element is Pt, and the element is tin (Sn).

[0177] Compared to other methods that use nanoparticles of one or more Group 10 elements and one or more metallic elements selected from tin (Sn), gallium (Ga), and indium (In) to obtain these catalysts, this method presupposes an advantageous approach because it implies lower costs in terms of the use of lower temperatures and implementation times. Simultaneously, the resulting catalyst compositions comprise nanoparticles with very low average diameters, making them highly useful in nODH reactions.

[0178] Throughout this specification and claims, the word "comprising" and its variations are not intended to exclude other technical features, additives, components, or steps. Furthermore, the word "comprising" covers situations where it means "composed of." Other objects, advantages, and features of the invention will become apparent to those skilled in the art upon review of this specification, or may be learned through practice of the invention. The following embodiments are provided for illustrative purposes only and are not intended to limit the invention. Moreover, the invention covers all possible combinations of the specific and preferred embodiments described herein.

[0179] Example

[0180] Example 1. Preparation of a single-metal nanocatalyst as a preliminary experimental product

[0181] Extensive research has been conducted on the preparation of single-metal Pt-nanocatalysts via organometallic methods, including the synthesis of single-metal colloids and supported Pt nanoparticles (Pt-NPs). For example, regarding Pt-colloid systems, the decomposition of Pt2(dba)3 organometallic precursors using various types of stabilizers (organic molecules acting as nanofabrication controllers), such as polymers (Pt1 with polyvinylpyrrolidone) and ligands (Pt2 and Pt3 with N- and P-ligands), has been reported. Depending on the gas and solvent properties, stabilizer / metal ratio, reactant concentration, and temperature, various shapes of Pt nanostructures have been obtained, such as isolated small Pt-NPs, dendritic crystals, or crystalline nanowires.

[0182] First, the effect of organic stabilizers was evaluated by preparing some colloidal Pt-NPs, which were obtained by decomposing Pt2(dba)3 in THF at 3 bar under H2 atmosphere and room temperature (rt), and stabilized with various organic molecules: none ( Figure 1 Pt4c THF), triphenylphosphine (PPh3), Figure 1 Pt4e) and 1,3-dimethylimidazolium carboxylate (NHC-CO2, Figure 1 (Pt4f). In all cases, the decomposition of the Pt precursor was quantitative, yielding small Pt-NPs in all cases. TEM image analysis of these samples showed Pt-NPs of 2-3 nm.

[0183] The effect of metal loading on the carrier:

[0184] The catalyst composition was then first produced using two mesoporous zeolites, NaZSM5 and HZSM5. The methods for obtaining the zeolites are known to those skilled in the art (see, for example...). (Et., (2008), as cited above). The synthesis was carried out in THF, although it is equally feasible in toluene. An organometallic approach was used, and NHC-CO2 was currently used as a stabilizer (i.e., as a source of carbene). First, the effect of metal loading was evaluated using NaZSM5. Five catalysts with different nominal metal loadings (Pt5a-Pt5e, 1, 2, 3, 4, and 5 wt%) were prepared by in-situ decomposition of Pt2(dba)3 in the presence of NHC-CO2 at 3 bar under H2 atmosphere and at room temperature. TEM analysis showed the formation of small (3-4 nm) nanoparticles in all cases. Figure 2 The study revealed that 1% by weight was the optimal metal loading, exhibiting a uniform Pt-NP distribution and the absence of aggregates. This method was also used to evaluate HZSM5. Other catalyst compositions were then prepared using alumina-based supports (Al2O3, Li-Al2O3). Li-Al2O3 supports can be prepared as known to those skilled in the art. In short, the Al2O3 support... 3-500 Solutions of lithium organometallic compounds (e.g., n-butyllithium) in polar solvents (e.g., cyclohexane) were added, and the solvent was washed off after the suspension was stirred overnight at room temperature (see Rouge et al., (2019), cited above). Pt-NPs loaded at 1 and 2 wt% on these alumina supports exhibited smaller Pt-NPs (1–2 nm) compared to Pt-NPs in NaZSM5.

[0185] The effect of PPh3 in bimetallic supported catalysts using toluene:

[0186] Although bimetallic catalysts are disclosed in more detail in Example 2 below, examples using PPh3 as an organic stabilizer and toluene as a solvent are also disclosed here. Pt 2 wt% – Sn 1 wt% and four supports were used: Al2O3 (Pt6c), Li-Al2O3 (Pt7c), Na-ZSM5 (Pt8c), and H-ZSM5 (Pt9c). Using PPh3 as a ligand resulted in the formation of small PtSn-NPs (i.e., 1-2 nm) on the four supports.

[0187] 1% Pt (prepared using PPh3 as an organic stabilizer and toluene as a solvent, as a comparison) on bare supports, Al2O3 (Pt6a), Li-Al2O3 (Pt7a), Na-ZSM5 (Pt8a), and H-ZSM5 (Pt9a), and as a comparative support, Al2O3 (Pt6b), Li-Al2O3 (Pt7b), Na-ZSM5 (Pt8b), and H-ZSM5 (Pt9b) were measured using a Micrometrics ASAP 2020 Physisorption instrument. The surface area measures (i.e., BET (Brunauer, Emmett, and Teller) isotherms, pore size, and pore distribution) of 2 wt% Pt-Sn stabilized with PPh3 on Al2O3 (Pt6c), Li (0.46%)-Al2O3 (Pt7c), Na-ZSM5 (Pt8c), and H-ZSM5 (Pt9c) were compared. Surface area is a measure of the exposed surface of a solid sample at the molecular scale. The BET theory is the most popular model for determining this area. The specific surface area of ​​a product can vary in processing methods, particularly in particle size reduction. Any subsequent changes in the manufacturing process can affect porosity and surface area. These changes can lead to unexpected variations in desired properties. Samples are typically prepared by heating while a gas is purged or flown over the sample to remove impurities. The prepared sample is then cooled with liquid nitrogen and analyzed by measuring the volume of gas adsorbed at a specific pressure. Therefore, the above samples were pretreated under vacuum at 250°C for 4 hours. The results regarding the alumina support are shown in Table 1. The area (i.e., 125 ± 9 m²) of the samples with and without NP is shown. 2 / g) and pore volume (0.65±0.06cm³) 3 The differences in ( / g) values ​​were not significant, which are attributed to the small differences in the efficiency of the pretreatment of each sample (i.e., the accuracy of the sample weighing method, the true vacuum achieved in the pretreatment, and the temperature, etc.). This means that the pores of the support are partially filled but not blocked, thus allowing for a comparison of the catalytic performance of these materials. Similar trends were observed using Na-ZSM5, H-ZSM5, and Li-Al2O3.

[0188] Table 1. BET results of alumina-supported catalysts

[0189] sample <![CDATA[BET(m 2 / g)]]> <![CDATA[Total pore volume (cm 3 / g)]]> <![CDATA[Al2O3 support]]> 116 0.69 <![CDATA[Pt6a Pt(1%)-PPh3@Al2O3]]> 134 0.71 <![CDATA[Pt6b Pt(2%)-PPh3@Al2O3]]> 113 0.60 <![CDATA[Pt6c Pt(2%) / Sn(1%)-PPh3@Al2O3]]> 126 0.71

[0190] Example 2 - Preparation of PtSn nanocatalysts with Sn(III and IV) precursors (catalyst composition of the present invention)

[0191] 2.1. Determination of organic stabilizers in PtSn colloidal NPs using Sn(III and IV) precursors

[0192] Bimetallic PtSn-NPs (Pt10) were prepared at room temperature and 3 bar under H2 with Pt2(dba)3 and SnBu4 as organometallic precursors in the presence of PPh3 as a possible phosphine (although all phosphines can be used) and toluene, at a Pt / Sn molar ratio of 1:1. By TEM, Pt10 exhibited small and well-dispersed NP sizes of 2.0–2.3 nm. Figure 3 (a)). These values ​​are consistent with those provided by XRD (grain size 1.25 ± 0.06 nm (data not shown)). Bimetallic PtSn NP(Pt11) without the use of PPh3 was also obtained. Figure 3 (b) However, the formation of aggregates was observed, demonstrating the positive effect of the phosphine (i.e., PPh3) stabilizer. Therefore, these results provide evidence for the importance of organic stabilizers in the one-step preparation of PtSn-NP via organometallic methods. (Washing solution) 31 The P NMR analysis did not show a phosphorus signal, indicating that phosphorus compounds were still present on the catalyst surface.

[0193] Then, different metal precursors and their combinations were analyzed. The decomposition of Pt and Sn precursors at 100 °C was monitored by GC-TCD quantification of certain products (i.e., methane and butane) arising from metathesis in aliquots of the reaction mixture collected at regularly timed intervals. The metal precursors are: for Pt, Pt... (0) 2(dba)3 and Pt (II) (COD)(Me)2, and for Sn(III) and Sn(IV), the precursors are, for example, SnBu4, HSnBu3, SnMe4, and Sn2Bu6. See the chemical formulas below, which also list other organometallic precursors that can be used to prepare the catalyst compositions of the present invention:

[0194]

[0195] The results showed that in the presence of SnBu4, the Pt precursor (Pt (0) 2(dba)3(Pt12) or Pt (II)(COD)(Me)2(Pt13)) decomposes quantitatively over a period of <15-20 hours, and SnBu4 decomposes partially over a period of >40 hours (2-4% for (Pt12) and 7-10% for (Pt13).

[0196] In Pt (II) In the presence of (COD)(Me)2 and over a period of >40 h, Sn(III) and Sn(IV) precursors decompose to less than 15%, for example, SnBu4 decomposes by 5-10% (Pt13) and HSnBu3 (Pt14) by 10% to 15%. Similar behavior was observed for SnMe4 (Pt15) and Sn2Bu6 (Pt16).

[0197] 2.2. Bimetallic Pt-Sn-NP supported using Sn(III and IV) precursors

[0198] The decomposition of Pt (O and II) and Sn (III and IV) precursors on four supports: Al₂O₃, Li-Al₂O₃, Na-ZSM₅, and H-ZSM₅ was performed. An overview of the synthesis of supported bimetallic NPs is provided in [the original text]. Figure 4 The decomposition was carried out at 100°C using Pt2(dba)3 and SnBu4 as organometallic precursors and phosphine (i.e., PPh3) as an organic stabilizer. Figure 4 The samples exhibited nominal metal loadings of 2% wt% Pt and 1% wt% Sn (Pt / Sn molar ratio of 1:1) and were labeled as Pt6c(Al2O3), Pt7c(Li-Al2O3), Pt8c(Na-ZSM5), and Pt9c(H-ZSM5). The decomposition of Pt and Sn precursors was monitored by inductively coupled plasma optical emission spectrometry (ICP-OES) and gas chromatography-TCD with a thermal conductivity detector to measure Pt and Sn content in the gas phase products generated from the decomposition of precursors and SEM-EDX. The average diameter and dispersion of nanoparticles were measured by HAADF-STEM (see [link to HAADF-STEM]). Figure 5 ), and the crystalline phase was studied by XRD.

[0199] The results showed (data not shown) that: (a) the Pt- precursor was quantitatively decomposed into small Pt-NPs, and the decomposition rate was unaffected by the support properties; (b) the Sn- precursor was partially decomposed, and the decomposition rate varied with the support properties in the order Al2O3(Pt6c) >> Li-Al2O3(Pt7c) = Na-ZSM-5(Pt8c) >> H-ZSM-5(Pt9c) >>> no support (the behavior is attributed to the presence of amphoteric protons, i.e., Al-OH groups, on the alumina surface); and (c) Sn(III and IV) precursors (e.g., SnBu4) decomposed very rapidly in the presence of Al2O3 (70 to 100% after 40 h). The higher reactivity of Al2O3 compared to H-ZSM-5 may be related to the larger and more readily accessible OH sites of the SnBu4 precursor within the support pore system. Furthermore, the Pt / Sn molar ratio of a large region (measurement area 500 nm x 500 nm) was investigated by ESEM-EDX to examine the presence of large aggregates and the homogeneity of the microstructure in different regions. The following observations were made: (a) the synthetic method produced small NPs that were well dispersed on the support; and (b) different Pt / Sn ratios were measured using ESEM depending on the region analyzed. In some regions, Sn was more abundant than Pt, indicating that the decomposition of the Sn precursor also occurred at the support site.

[0200] Not confined to a single theory, Figure 6 The paper presents a possible mechanism for the decomposition of Pt and Sn when using the aforementioned precursors (based on Basset et al., (1998), Surface Organometallic Chemistry on Metals: Stable Precursors for Surface Alloys Obtained by Stepwise Hydrogenolysis of Sn(n-C4H9)4 on Silica-Supported Platinum Particles). Formation of Sn(n-C4H9)n fragments (Surface Organometallic Chemistry on Metals: Formation of a Stable) Sn(n-C4H9)n Fragment as a Precursor of Surface Alloy Obtained by Stepwise Hydrogenolysis of Sn(n-C4H9)4 on a Platinum Particle Supported on Silica (J. Am. Chem. Soc. 120, 1, 137-146). The mechanism can be summarized in two steps: Step 1 ( Figure 6(a) Sn and Pt precursors begin to react. The Pt precursor (Pt2(dba)3) is hydrogenated, releasing hydrogenated dbaH4. Simultaneously, bare Pt(0) metal atoms begin to grow and nucleate, forming Pt-NPs with hydrides on their surfaces. Meanwhile, the Sn precursor (Sn... (IV) Bu4 (tetrabutyltin) reacts with the -OH groups present in the support, releasing butane molecules each time; step 2 ( Figure 6 (B) Once Pt-NP is formed, Sn can react with the support or Pt-NP.

[0201] Complete characterization of the selected PtSn nanocatalysts:

[0202] This section describes the characterization of four bimetallic Pt / Sn systems stabilized with PPh3 on four different supports (Al2O3 (Pt6c), Li-Al2O3 (Pt7c), Na-ZSM-5 (Pt8c), and H-ZSM-5 (Pt9c)). Table 2 presents a summary of the characterization of the four bimetallic supported catalysts.

[0203] HAADF-STEM. High-angle annular dark-field imaging scanning transmission electron microscopy images were obtained using the FEI TITAN. The average diameter and particle distribution are shown in Table 2. The average diameter ranges from 1.2 to 1.6 nm (Pt6c to Pt9c), confirming the small influence of the support on the nanoparticle size.

[0204] SEM-EDX Two distinct regions of the same sample (Pt6c) were analyzed using scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX): one region with NP analysis and one region without NP, denoted as Spectrum 1 and Spectrum 2 (data not shown). In both cases, C signals (from the support), Al and O (from the support), and Pt and Sn contents varied with region analysis. Although NP was not analyzed in Spectrum 2, Sn was detected in the EDX analysis, confirming the previously described mechanism. Therefore, controlling the composition of Sn is important.

[0205] XRD.X-ray diffraction (XRD) patterns of four Pt / Sn samples (Al₂O₃ (Pt₆c), Li-Al₂O₃ (Pt₇c), Na-ZSM-5 (Pt₈c), and H-ZSM-5 (Pt₉c)) were collected using a Bruker D8 Discover diffractometer and compared with the bare support. The XRD patterns of the loaded systems showed only very small signals corresponding to the metallic phase, due to the low metal loading, small particle size (i.e., a smaller FWHM implies a larger particle size, thus resulting in broader peaks), and the support signal being completely overshadowed by the strongest signals generated by Sn and Pt (data not shown). A comparison of the diffraction patterns of the loaded system (Pt₆c) on Al₂O₃ (data not shown) with the previously reviewed colloidal bimetallic nanoparticle system Pt₁₂ (Pt / Sn-PPh₃) confirms that the observed peaks correspond to the same crystalline phase (i.e., the Pt phase peaks did not migrate due to the low Sn content in the final material).

[0206] Table 2. Summary of characterization of bimetallic PtSn-PPh3 supported nanocatalysts

[0207]

[0208] a Particle size was determined by measuring more than 200 nanoparticles randomly selected from HAADF STEM images. b The Sn / Pt molar ratio was determined by elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0209] c The molar ratios of Sn / Pt, Sn(δ+) / Sn(0) and Pt(δ+) / Pt(0) were determined by XPS analysis.

[0210] The surface area was determined by Brunauer-Emmett-Teller (BET) analysis. The surface area results for the Pt / Sn samples (Al2O3 (Pt6c), Li-Al2O3 (Pt7c), Na-ZSM-5 (Pt8c), H-ZSM-5 (Pt9c)) are collected in Table 2. The differences in surface area and pore volume values ​​between samples containing and without NP are not significant, attributed to the small differences in the efficiency of the individual sample pretreatment (i.e., the accuracy of the sample weighing method, the actual vacuum and temperature achieved in the pretreatment, etc.). This implies that the pores of the support are partially filled without being blocked, thus allowing for comparison of the catalytic performance of these materials. No significant differences in surface area and pore volume were observed when NP was loaded, indicating that the pores of the support are partially filled without being blocked.

[0211] XPSX-ray photoelectron spectroscopy (XPS) was performed using a SPECS PHOIBOS 150 spectrophotometer. Four bimetallic Pt / Sn samples (Al₂O₃ (Pt₆c), Li-Al₂O₃ (Pt₇c), Na-ZSM₅ (Pt₈c), and H-ZSM₅ (Pt₉c)) were analyzed, and the obtained XPS spectra were processed using CASAXPS software to estimate the composition at the support surface and the estimated ratios between different Pt and Sn forms (see Table 2). Correlation deconvolution was performed using the reported binding energies from Sn and Pt. Comparison of the bulk Sn / Pt ratio (ICP-OES value) and the surface Pt / Sn ratio (XPS value) revealed partial segregation of Sn on the Pt surface (i.e., a Pt-rich core and a Sn-rich shell). The extent of this behavior depends on the carrier, with the segregation order being: Na-ZSM-5(Pt8c) > Al2O3(Pt6c) > Li-Al2O3(Pt7c) > H-ZSM-5(Pt9c). Regarding the Sn(δ+) / Sn(0) ratio, the order is: Al2O3(Pt6c) > H-ZSM-5(Pt9c) > Na-ZSM-5(Pt8c) > Li-Al2O3(Pt7c). This difference is attributed to the formation of more Sn. IV The reaction of SnBu4 with the surface material of the support (i.e., Sn) IV Bu4+4Al-OH=Sn IV (AlO)4+Bu-H) with SnBu4 preferably reacting with Pt-NP hydride (nPt) 0 -NP-H+Sn IV Bu4=Pt 0 n Sn 0 The difference in the degree of Pt(δ+) / Pt(0) ratios compared to the catalysts of -NP+4Bu-H is significant. Regarding the Pt(δ+) / Pt(0) ratio, the order is somewhat similar to that of the Sn(δ+) / Sn(0) ratio: Al2O3(Pt6c)≈H-ZSM-5(Pt9c)≈Na-ZSM-5(Pt8c)>Li-Al2O3(Pt7c). This behavior is attributed to the protective effect against oxidation provided by the Sn material on the Pt(0) surface atoms.

[0212] Examples 1 and 2 demonstrate several combinations of porous supports, organic stabilizers, and organometallic precursors that can be used to obtain the catalytic compositions of the present invention through a simple preparation method. The method requires no pretreatment of the support with any co-catalyst and / or any calcination step after the addition of the catalyst, nor any further deposition of the co-catalyst. Furthermore, the method does not involve any lengthy sequence of steps involving different temperatures.

[0213] Example 3. Preparation of PtSn nanocatalysts using Sn(II) precursor

[0214] 3.1. Analysis of organic stabilizers in PtSn colloidal NPs using Sn(II) precursors

[0215] Colloidal PtSn nanoparticles were prepared by reacting Pt2(dba)3 with N,N'-di-tert-butyl-2,3-diamidobutanetin (abbreviated as Sn(II)C). 12 H 26 The decomposition is performed on the N2 precursor. 5 Using Pt2(dba)3 and N,N'-di-tert-butyl-2,3-diamidobutanetin (abbreviated as Sn(II)C) under a Pa H2 atmosphere and at room temperature or 100°C. 12 H 26 The N2 precursor was used as an organometallic precursor, and PPh3 and N-heterocyclic carbenes were used as organic stabilizers. Different solvents (tetrahydrofuran and toluene) and temperatures (room temperature and 100 °C) were also determined. The decomposition of the Pt and Sn precursors at 100 °C was monitored by measuring the Pt and Sn contents using inductively coupled plasma optical emission spectroscopy (ICP-OES) and SEM-EDX. The average diameter and dispersion of the nanoparticles were measured by HAADF-STEM, and the crystalline phase was studied by XRD (see Table 3).

[0216] Table 3. Summary of characterization of bimetallic PtSn colloidal NPs using Sn(II) precursors

[0217]

[0218] a Particle size was determined by measuring more than 200 nanoparticles randomly selected from HAADF STEM images. b The Sn / Pt molar ratio was determined by elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES). c The crystalline phase and grain size were determined by XRD.

[0219] Bimetallic PtSn-rt (Pt17) was prepared using Pt2(dba)3 and N,N'-di-tert-butyl-2,3-diamidobutanetin as organometallic precursors at a Pt / Sn molar ratio of 1:1 in the absence of stabilizers and in the absence of tetrahydrofuran under rt and 3 bar H2. TEM analysis confirmed that Pt17 exhibited a size of 2.7 ± 1.6 nm. XRD diffraction patterns of Pt17 showed that Ptfcc was the dominant crystalline phase with a grain size of 1.61 nm, implying that the measured NP was approximately 1.5 times the grain size.

[0220] For comparison, the same colloidal PtSn-100Pt18 was prepared without any stabilizers, but this time the reaction mixture was heated at 100 °C. Pt18 showed agglomerates with a size of 4.9 ± 1.9 nm as indicated by TEM. The XRD diffraction pattern of Pt18 showed a dominant hexagonal PtSn crystalline phase and a grain size of 4.80 nm, matching the size obtained by TEM.

[0221] The effect of ligands was also investigated by using N-heterocyclic carbides (NHC-CO2) or triphenylphosphine (PPh3) with tetrahydrofuran or toluene (at 3 bar and H2).

[0222] In the presence of NHC, small and well-dispersed nanoparticles (PtSn-NHC-rtNP(Pt19)) of 2.5 ± 0.9 nm were obtained at room temperature. The XRD diffraction pattern of Pt19 showed a dominant Pt fcc crystalline phase and a grain size of 0.93 nm, implying that the measured NPs were approximately twice the grain size. The significant difference observed by TEM and XRD may indicate that the particles observed by TEM consisted of several independent crystals, or that the resolution of the transmission microscope did not allow for the monitoring of nanoparticles smaller than 1 nm.

[0223] If the reaction occurs at 100 °C, small agglomerates (PtSn-NHC-100(Pt20)) with a size of 5.0 ± 3.0 nm are obtained. In this case, the effect of temperature promotes the agglomeration of NPs. The XRD diffraction pattern of Pt20 shows a dominant hexagonal PtSn grain phase and a grain size of 3.14 nm. In this case, the size of the nanoparticles is inconsistent with the size measured in TEM. The smallest unit (grain) is estimated to be around 3.0 nm.

[0224] In the presence of PPh3, small and well-dispersed nanoparticles (PtSn-PPh3-rtNP(Pt21)) of 1.87 ± 0.83 nm were obtained at room temperature. The XRD diffraction pattern of Pt21 showed a dominant Pt fcc crystalline phase and a grain size of 0.57 nm, implying that the measured NP was approximately twice the grain size.

[0225] If the reaction occurs at 100 °C, small and well-dispersed nanoparticles of 2.33 ± 1.05 nm (PtSn-PPh3-100(Pt22)) are also obtained. XRD analysis of Pt22 reveals a dominant Pt fcc crystalline phase and a grain size of 0.57 nm. Notably, increasing the temperature (from room temperature to 100 °C) does not show a direct effect on the crystalline phase, as the Pt fcc phase is maintained and does not form an alloy. In the original diffraction pattern, the dominant Pt band at 39.76° is significantly shifted, and a possible shoulder appears near 36°. Therefore, to confirm that the sample does not contain only Pt NP, Pt22 was calcined at 900 °C, and the XRD diffraction pattern was examined again. After this heat treatment, the width of the NP characteristic band disappeared, and nanoparticles grew. Furthermore, two distinct alloying phases were generated: a hexagonal PtSn phase and a hexagonal Pt2Sn3 phase. The binary phase diagram of the PtSn system was studied, and it was determined that the PtSn and Pt2Sn3 phases could not be formed by temperature alone. Therefore, only the crystallinity of PtSn and Pt2Sn3 NPs must be increased, and the alloy can be detected more accurately. Thus, this experiment clearly demonstrates that the synthesis of colloidal NPs using PPh3 ligands at 100°C yields bimetallic NPs.

[0226] The PPh3 moiety appears to be a suitable ligand for the preparation of small, well-distributed nanoparticles formed by the decomposition of Pt2(dba)3 and N,N'-di-tert-butyl-2,3-diamidobutanetin, independent of the temperature used. Therefore, these results provide evidence for the importance of organic stabilizers in the one-step preparation of PtSn NPs via organometallic methods. (The text abruptly ends here, likely due to an incomplete sentence or missing information.) 31 P NMR analysis showed no phosphorus signal, indicating that phosphorus compounds were retained on the catalyst surface.

[0227] The molar relationship of Pt:Sn was assessed by ICP-OES and found to be lower than that initially added, although it was closer to the nominal value of 1 when the nanoparticles were prepared at 100 °C. A comparison of bimetallic PtSn NPs without ligands (Pt17, Pt18) and with those using N-heterocyclic carbenes (Pt19, Pt20) or PPh3 (Pt21, P22) reveals the importance of organic stabilizers for the one-step preparation of PtSn-NPs via organometallic methods.

[0228] The results showed that Pt (0) 2(dba)3 and N,N'-di-tert-butyl-2,3-diamidotin butane (abbreviated as Sn(II)C) 12 H 26Both N2 and Sn(II) undergo quantitative decomposition within a relatively short time period (<15-20 h). In contrast, in Example 2, Sn(IV) and Sn(II) decompose only partially. Therefore, this method allows for the preparation of PtSn nanocatalysts with different Sn loadings based on the precursors. Thus, all test conditions are the working conditions used for catalyst preparation.

[0229] 3.2. Bimetallic Pt-Sn-NP supported using Sn(II) precursor

[0230] Pt2(dba)3 and N,N'-di-tert-butyl-2,3-diamidobutanetin (abbreviated as Sn(II)C) were subjected to Pt2(dba)3 and N,N'-di-tert-butyl-2,3-diamidobutanetin (abbreviated as Sn(II)C) on two supports, Al2O3 and H-ZSM5. 12 H 26 Decomposition of N2 precursor. The decomposition occurs at 3 x 10⁻⁶ ℃. 5 The procedure is carried out under a Pa H2 atmosphere and at room temperature or 100°C, using Pt2(dba)3 and N,N'-di-tert-butyl-2,3-diamidotin (abbreviated as Sn(II)C). 12 H 26 The N2 precursor was used as the organometallic precursor, and PPh3 and N-heterocyclic carbene were used as organic stabilizers. These samples, exhibiting a nominal metal loading of 2 wt% Pt and 1 wt% Sn (Pt / Sn molar ratio 1:1), were labeled as Pt23 (Al2O3 and N-heterocyclic carbene, at 100 °C), Pt24 (Al2O3 and PPh3, at room temperature), Pt25 (Al2O3 and PPh3, at 100 °C), and Pt26 (H-ZSM-5 and PPh3, at 100 °C). The decomposition of the Pt and Sn precursors at 100 °C was monitored by measuring Pt and Sn contents using inductively coupled plasma optical emission spectroscopy (ICP-OES) and SEM-EDX. The average diameter and dispersion of the nanoparticles were measured by HAADF-STEM, and the crystalline phase was studied by XRD (see Table 4).

[0231] PtSn nanoparticles prepared using PPh3 as a stabilizer exhibited small average diameters. The average diameter of sample Pt25, prepared at 100 °C (1.4 ± 0.3 nm), was smaller than that of sample Pt24, prepared at room temperature (1.8 ± 0.3 nm). Regarding the NHC ligand, Pt26 exhibited a similar average nanoparticle diameter (1.5 ± 0.3 nm) to Pt24 and Pt25. Pt26 showed a small average nanoparticle diameter (1.5 ± 0.3 nm), but slightly larger than the average diameter obtained under the same conditions using an Al2O3 support.

[0232] Table 4. Summary of characterization of bimetallic Pt-Sn-NPs loaded with Sn(II) precursors

[0233]

[0234] a Particle size was determined by measuring more than 200 nanoparticles randomly selected from HAADF STEM images. b The Sn / Pt molar ratio was determined by elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0235] Comparing the colloidal nanoparticles described above in Table 3 with the loaded nanoparticles described here (Table 4), regarding nanoparticle size, smaller average nanoparticle diameters and narrower dispersions (1.4–2.0, see Table 4) were measured for the loaded system compared to those measured for the colloidal system (i.e., 1.9–5.0, see Table 3).

[0236] Regarding ICP-OES, the Sn / Pt (mol / mol) ratio (1.13–1.18, see Table 4) was measured for the loaded system, compared to the ratio measured for the colloidal system (i.e., 1.23–1.53, see Table 3).

[0237] Regarding XRD, no metal-related peaks were detected for all the supported catalysts (Pt23 to Pt25) in this section, and the resulting diffraction patterns were directly identical to those of the bare support. This is because the amount of metal present on the catalyst is in the range of 1.0–2.0%.

[0238] The PPh3 moiety appears to be a suitable stabilizer for the preparation of small-sized and well-distributed supported nanoparticles formed by the decomposition of Pt2(dba)3 and N,N'-di-tert-butyl-2,3-diamidobutanetin, independent of the temperature and support used. Therefore, these results once again provide evidence for the importance of organic stabilizers in the one-step preparation of PtSn NPs via organometallic methods. (The text abruptly ends here, likely due to an incomplete sentence or missing information.) 31 The P NMR analysis did not show a phosphorus signal, indicating that the phosphorus compounds were still on the catalyst surface.

[0239] The results revealed (data not shown) that: (a) the Pt precursor was quantitatively decomposed into small Pt-NPs, and the decomposition rate was unaffected by the support properties; (b) the Sn precursor was quantitatively decomposed. Furthermore, the Pt / Sn molar ratio in a larger region (measured over an area of ​​500 nm x 500 nm) was investigated by ESEM-EDX to examine the presence of large aggregates and the homogeneity of the microstructure in different regions. The following was observed: (a) the synthetic procedure produced small NPs well dispersed on the support; and (b) different Pt / Sn ratios were measured using ESEM, depending on the region analyzed. In some regions, Sn was more abundant than Pt, indicating that Sn precursor decomposition also occurred at the support site.

[0240] Not confined to any particular theory, possible mechanisms for the decomposition of Pt and Sn using the aforementioned precursors are proposed as follows: Figure 6 (Based on Basset et al., (1998)).

[0241] Example 4. Preparation of PtGa nanocatalysts using Ga precursors

[0242] 4.1. Determination of Organic Stabilizers in PtGa Colloidal NP

[0243] Colloidal PtGa nanoparticles were prepared by decomposition of Pt2(dba)3 and trimethylgallium (GaMe3) precursors. The decomposition was carried out at a concentration of 3 x 10⁻⁶. 5 The experiments were conducted under a Pa H2 atmosphere and at room temperature or 100 °C, using Pt2(dba)3 and trimethylgallium (GaMe3) precursors as organometallic precursors, and PPh3 and N-heterocyclic carbides as organic stabilizers. Different solvents (tetrahydrofuran and toluene) and temperatures (room temperature and 100 °C) were also determined. The decomposition of Pt and Ga precursors at 100 °C was monitored by measuring Pt and Sn contents using inductively coupled plasma optical emission spectroscopy (ICP-OES) and SEM-EDX. The average diameter and dispersion of nanoparticles were measured by HAADF-STEM, and the crystalline phase was studied by XRD (see Table 5).

[0244] Bimetallic PtGa-NP was prepared using Pt2(dba)3 and trimethylgallium in a 1:1 Pt / Ga molar ratio, with carbene (Pt27) and triphenylphosphine ligand (Pt28) and tetrahydrofuran and toluene, respectively, at 100 °C and 3 bar H2 for 20 h.

[0245] Regarding nanoparticle size, PtGa-NHC (Pt27) exhibits a smaller average nanoparticle diameter and a narrower distribution compared to PtGa-PPh3 (Pt28). Regarding the Pt / Ga molar ratio, PtGa-NHC (Pt27) shows a slightly smaller Pt / Sn molar ratio compared to PtGa-PPh3 (Pt28).

[0246] Table 5. Summary of characterization of bimetallic PtGa colloidal NP

[0247] catalyst <![CDATA[NP size a (nm)]]> <![CDATA[ICP Ga / Pt b (Moore)]]> Pt27(PtGa-NHC-100) 0.8±0.2 1.20 <![CDATA[Pt28(PtGa-PPh3-100)]]> 1.4±0.4 1.13

[0248] a Particle size was determined by measuring more than 200 nanoparticles randomly selected from HAADF STEM images. b The Sn / Pt molar ratio was determined by elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0249] The use of two bimetallic PtGa NPs, N-heterocyclic carbides (Pt27) and PPh3 (Pt28), reveals the importance of organic stabilizers in preventing aggregate formation and stabilizing small, well-dispersed nanoparticles. Therefore, these results provide evidence for the importance of organic stabilizers in the one-step preparation of PtSn-NPs via organometallic methods. As a characterization method for the nanoparticles, a washing solution of PtGa NP (Pt28) using PPh3 was used. 31 P NMR analysis showed that phosphorus compounds were still present on the catalyst surface.

[0250] The results show that Pt (0) 2(dba)3 and GaMe3 decomposed quantitatively within a timeframe of <15-20 h, and the precursors functioned well within the desired yield range for catalyst synthesis. Therefore, all tested conditions were those used for catalyst preparation.

[0251] 4.2. Loaded bimetallic Pt-Ga-NP

[0252] The decomposition of Pt2(dba)3 and trimethylgallium (GaMe3) precursors was performed on four supports: Al2O3, Li-Al2O3, Na-ZSM5, and H-ZSM5. The decomposition was carried out at 100 °C, using Pt2(dba)3 and trimethylgallium (GaMe3) precursors as organometallic precursors and PPh3 and N-heterocyclic carbenes as organic stabilizers. These samples exhibited nominal metal loadings of Pt 2 wt% - Ga 1 wt% (Pt / Ga molar ratio of 1:1) and were labeled Pt29 (Al2O3 and PPh3), Pt30 (Li-Al2O3 and PPh3), Pt31 (H-ZSM-5 and PPh3), and Pt32 (Na-ZSM-5 and PPh3). The decomposition of Pt and Ga precursors at 100 °C was monitored by measuring Pt and Sn contents using inductively coupled plasma optical emission spectroscopy (ICP-OES) and SEM-EDX. The average diameter and dispersion of nanoparticles were measured by HAADF-STEM, and the crystalline phase was studied by XRD (see Table 6).

[0253] Table 6. Characterization summary of bimetallic PtGa-loaded NPs

[0254]

[0255] a Particle size was determined by measuring more than 200 nanoparticles randomly selected from HAADF STEM images. b The Sn / Pt molar ratio was determined by elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0256] Comparing the colloidal nanoparticles described above in Table 5 with the loaded nanoparticles described here (Table 6), regarding nanoparticle size, similar average nanoparticle diameters and narrower dispersions (1.2–1.4, see Table 5) were measured for the loaded system compared to those measured for the colloidal system (i.e., 1.4, see Table 6).

[0257] Regarding ICP-OES, the Ga / Pt molar ratio measured for the loaded system depends on the support, but generally the value (1.13–1.6–8.95, see Table 6) is lower than that measured for the colloidal system (i.e., 1.13–1.2–0.85, see Table 5).

[0258] Regarding XRD, no metal-related peaks were detected for all the supported catalysts (Pt29 to Pt32) in this section, and the resulting diffraction patterns were directly identical to those of the bare support. This is because the amount of metal present on the catalyst is 1.0–2.0%.

[0259] The PPh3 moiety appears to be a suitable stabilizer for the preparation of small-sized and well-distributed loaded nanoparticles formed from the decomposition of Pt2(dba)3 and trimethylgallium (GaMe3), independent of the temperature and support used. Therefore, these results once again demonstrate the importance of organic stabilizers for the one-step preparation of PtSn NPs via organometallic methods. (The text abruptly ends here, likely due to an incomplete sentence or missing information.) 31 The P NMR analysis did not show a phosphorus signal, indicating that the phosphorus compounds were still on the catalyst surface.

[0260] The results revealed (data not shown) that: (a) the Pt precursor was quantitatively decomposed into small Pt-NPs, and the decomposition rate was not affected by the support properties; (b) the Ga precursor was partially decomposed (i.e., 70 to 90%), and the decomposition rate varied with the support, in the order Al2O3 >> Li-Al2O3 without support (this behavior is attributed to the presence of amphoteric protons, i.e., Al-OH groups, on the alumina surface); and (c) GaMe3 decomposed quite rapidly in the presence of PPh3 and Al2O3 (70% and 90% after 20 and 40 h, respectively).

[0261] Furthermore, the Pt / Ga molar ratio over a larger area (measured over an area of ​​500 nm x 500 nm) was investigated using ESEM-EDX to examine the presence of large aggregates and the uniformity of the microstructure in different regions. The following were observed: (a) the synthetic procedure produced small NPs well dispersed on the support; and (b) using ESEM, different Pt / Ga ratios were measured depending on the region analyzed. In some regions, Ga was more abundant than Pt, indicating that decomposition of the Ga precursor also occurred at the support site.

[0262] Not confined to any single theory, possible mechanistic suggestions for the Pt and Ga systems (given the similar reactivity of Sn (Group 14) and Ga (Group 13) organometallic precursors) may be similar to those discussed above. Figure 6 The decomposition mechanism of Pt and Sn proposed in [the study] is related to that proposed in [the study] (based on Basset et al., (1998)).

[0263] Example 5. Preparation of NiSn nanocatalysts using Sn precursors

[0264] 5.1. Determination of organic stabilizers in NiSn colloidal NP using Sn precursor

[0265] Colloidal NiSn nanoparticles were prepared by decomposition of Ni(COD)2 and SnBu4 precursors. The decomposition occurred at a concentration of 3 x 10⁻⁶. 5 The experiments were conducted under a Pa H2 atmosphere and at room temperature or 100 °C, using Ni(COD)2 and SnBu4 precursors as organometallic precursors and PPh3 and N-heterocyclic carbenes as organic stabilizers. Different solvents (tetrahydrofuran and toluene) and temperatures (room temperature and 100 °C) were also determined. The decomposition of Ni and Sn precursors was monitored by inductively coupled plasma optical emission spectroscopy (ICP-OES), gas chromatography-TCD analysis of products in the gas phase resulting from precursor decomposition, and SEM-EDX measurement of Pt and Sn content. The average diameter and dispersion of nanoparticles were measured by HAADF-STEM, and the crystalline phase was studied by XRD.

[0266] Bimetallic NiSn-NP (Ni1) was prepared at 100 °C and 3 bar under H2 conditions using Ni(COD)2 and SnBu4 with a Ni / Sn molar ratio of 1:1 as organometallic precursors, N-heterocyclic carbides, and tetrahydrofuran. TEM analysis revealed that Ni1 exhibited an ultrasmall NP size of less than 1.5 nm.

[0267] Bimetallic NiSn-NP (Ni2) was prepared in H2 at 100 °C and 3 bar using Ni(COD)2 and SnBu4 with a Ni / Sn molar ratio of 1:1 as organometallic precursors, PPh3, and toluene. TEM analysis revealed that Ni2 exhibited an ultrasmall NP size of less than 1.5 nm.

[0268] Then, different solvents (tetrahydrofuran and toluene) and temperatures (room temperature and 100 °C) were determined. The decomposition of Ni and Sn precursors at 100 °C was monitored by measuring Ni and Sn contents using inductively coupled plasma optical emission spectroscopy (ICP-OES) and scanning electron microscopy (SEM):EDS (energy-dispersive X-ray spectroscopy), and the crystalline phase was studied by XRD.

[0269] The results showed that the Ni(COD)2 precursor was quantitatively decomposed within a time period of <15-20h, and SnBu4 was partially decomposed (2-10%) within a time period of >40h.

[0270] 5.2. Bimetallic Ni-Sn-NP Supported Using Sn Precursor

[0271] The decomposition of Ni(COD)2 and SnBu4 precursors was performed on two supports, Al2O3 and Li(0.46%)-Al2O3. The decomposition was carried out at 100 °C, using Ni(COD)2 and SnBu4 precursors as organometallic precursors and PPh3 and N-heterocyclic carbides as organic stabilizers. These samples exhibited nominal metal loadings of 2 wt% Ni to 3.75 wt% Sn (Ni / Sn molar ratio of 1:1) and were labeled Ni3 (Al2O3 and PPh3), Ni4 (Al2O3 and NHC), Ni5 (Li-Al2O3 and PPh3), and Ni6 (Li-Al2O3 and NHC). The decomposition of Ni and Sn precursors at 100 °C was monitored by inductively coupled plasma optical emission spectroscopy (ICP-OES) and SEM-EDX, the average diameter and dispersion of nanoparticles were measured by HAADF-STEM, and the crystalline phase was studied by XRD.

[0272] Table 7. Summary of characterization of bimetallic NiSn-loaded NPs

[0273]

[0274] a Particle size was determined by measuring more than 200 nanoparticles randomly selected from HAADF STEM images. b The Sn / Pt molar ratio was determined by elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES).

[0275] Regarding ICP-OES, the Sn / Ni molar ratio measured for the loaded system depends on the stabilizer, but generally, the value using PPh3 (0.34-0.39, see Table 7) is higher than the value using NHC (i.e. 0.06, see Table 7).

[0276] Regarding XRD, no metal-related peaks were detected for all the supported catalysts (Ni3 to Ni4) in this section, and the resulting diffraction patterns were directly identical to those of the bare support. This is because the amount of metal present on the catalyst is 1.0–2.0%.

[0277] The PPh3 moiety appears to be a suitable stabilizer for the preparation of small-sized and well-distributed supported nanoparticles formed from the decomposition of Ni(COD)2 and SnBu4, independent of the temperature and support used. Therefore, these results once again demonstrate the importance of organic stabilizers for the one-step preparation of NiSn NPs via organometallic methods. (The text then abruptly shifts to a seemingly unrelated topic: washing solution...) 31 The P NMR analysis did not show a phosphorus signal, indicating that the phosphorus compounds were still on the catalyst surface.

[0278] The results obtained (data not shown) indicate that: (a) the Ni-precursor was quantitatively decomposed to form small Ni-NPs, and the decomposition rate was not affected by the properties of the support; (b) the Sn-precursor was partially decomposed, and the decomposition rate varied with the properties of the stabilizer (in the order PPh3 >> N-heterocyclic carbene) and the support (in the order Al2O3 >> Li-Al2O3 without support) (this behavior is attributed to the presence of amphoteric protons, i.e., Al-OH groups, on the alumina surface); and (c) SnBu4 decomposed by 35-45% after 40 h in the presence of PPh3 and Al2O3; and SnBu4 decomposed by 7-10% after 40 h in the presence of N-heterocyclic carbene and Al2O3.

[0279] Furthermore, the Ni / Sn molar ratio over a larger area (measured over an area of ​​500 nm x 500 nm) was investigated using ESEM-EDX to examine the presence of large aggregates and the uniformity of the microstructure in different regions. The following were observed: (a) the described synthesis method produced small NPs well dispersed on the support; and (b) using ESEM, different Ni / Sn ratios were measured depending on the region analyzed. In some regions, Sn was present in greater proportion than Ni, indicating that Sn precursor decomposition also occurred at the support site.

[0280] Not confined to any particular theory, possible mechanistic schemes for the Ni and Sn systems (since Pt and Ni belong to Group 10) may be similar to those discussed above. Figure 6 The decomposition mechanism of Pt and Sn proposed in [the study] is related to that proposed in [the study] (based on Basset et al., (1998)).

[0281] Example 6. n-ODH using bimetallic nanocatalysts

[0282] Then, the Pt / Sn nanocatalysts of Example 2 (using Al2O3 and PPh3 (Pt6c), Li-Al2O3 and PPh3 (Pt7c), Na-ZSM-5 and PPh3 (Pt8c), H-ZSM-5 and PPh3 (Pt9c)) and Example 3 (using Al2O3 and N-heterocyclic carbides (Pt23), Al2O3 and PPh3 (Pt25)) and H were evaluated in non-oxidative dehydrogenation (n-ODH) (i.e., n-ODH of propane for selective production of propylene and n-ODH of butane / butene for selective production of butadiene) and aromatization reactions (propane aromatization for the production of benzene), and in Example 3 (using Al2O3 and N-heterocyclic carbides (Pt23), Al2O3 and PPh3 (Pt25) and H Samples from Example 4 (Pt / Sn nanocatalysts using Al2O3 and PPh3 (Pt26), Li-Al2O3 and PPh3 (Pt30), H-ZSM-5 and PPh3 (Pt31), and Na-ZSM-5 and PPh3 (Pt32)) and Example 5 (Ni / Sn nanocatalysts using Al2O3 and PPh3 (Ni3), Al2O3 and N-heterocyclic carbides (Ni4), Li-Al2O3 and PPh3 (Ni5), and Li-Al2O3 and N-heterocyclic carbides (Ni6)).

[0283] The catalytic unit for the non-oxidative dehydrogenation reaction consists of a stainless steel fixed-bed reactor system connected online to the GC-TCD / MS system. The reaction is carried out under conditions excluding O2 and H2O. Argon (5.0, 99.999% purity), N2 (5.0, 99.999% purity), H2 (5.0, 99.999% purity), propane (3.5, 99.95% purity), butane (3.5, 99.95% purity), and 2-butene (3.5, 99.95% purity) are purified online using molecular sieves and a BTS catalyst trap to ensure high purity is maintained. A mass flow controller and a bypass 3-port valve system control the composition and flow rate to the reactor or directly to the analysis system. Pressure is monitored and controlled by: (a) a pressure sensor at the reactor inlet, (b) a pressure regulator with a pressure gauge at the reactor outlet, and (c) a safety valve (adjusted to a maximum of 5 bar) to prevent overpressure. The temperature is controlled by a temperature heating jacket with thermocouples inside the reactor, called Hobersal.

[0284] First, the reaction system setup experiment was completed, including the calibration of the mass flow controller and the preparation of a temperature program for heating the reaction without overheating the catalyst. Subsequently, the analytical method was prepared by injecting a standard gas sample into the GC-TCD / MS system, allowing for the identification of reaction products, preparation of calibration curves, and determination of the response factor. For catalytic testing, catalyst preparation was carried out in a glove box to avoid oxidation. 1–100 mg of catalyst (i.e., 25.0 mg catalyst, 0.1 mg Pt) was dispersed in a known amount of silicon carbide. The catalyst is then placed into the reactor. The catalyst pretreatment includes a reduction procedure of 4-16 h at 500-600 °C (1 °C / min) and a pressure of 0.5 to 3 bar absolute under an H2 gas flow.

[0285] For example, the selected initial conditions for non-oxidative dehydrogenation (n-ODH) of propane are: temperature: 530 °C; pressure: 1 bar; and gas flow rates: 3 mL / min propane, 21 mL / min Ar and 1 mL / min H2.

[0286] Propane conversion and propylene selectivity were determined by gas chromatography-TCD analysis of gas samples acquired at regular time intervals (every 14 min). Argon was used as an internal standard to determine the response factors for propane and propylene. The mathematical formulas used to determine the conversion and selectivity are as follows:

[0287]

[0288]

[0289] Table 8(a) below lists the results obtained by non-oxidative dehydrogenation of propane (PDH) using some of the catalyst compositions of the present invention. Comparative data with the benchmark Statoil catalyst (currently known as LINDE-Basf Statoil) are also included.

[0290] Table 8(a). Propane dehydrogenation (PDH) catalyzed by Pt / Sn and Ni / Sn nanocatalysts

[0291]

[0292] Statoil catalyst (SnPt / Mg(Al)O) (US2005003960A1, STATOIL ASA, incorporated herein by reference) is considered a benchmark catalyst for establishing reaction and analytical methods. For comparative purposes, in this example, it was tested in a PDH under the same reaction conditions as our catalyst. Catalytic testing using bimetallic Pt / Sn catalysts (Al2O3 (Pt6c and Pt25), Li-Al2O3 (Pt7c)), Pt / Ga catalyst (Pt29), and Ni / Sn catalysts (Al2O3 and PPh3 (Ni3)) provided more competitive performance relative to the benchmark catalyst. These catalysts offer highly selective (selectivity greater than 99%) conversion of propane feedstock, with conversion (23-25% at 530 °C and 1 bar) and stability significantly higher than the reference catalyst. The Pt / Sn catalyst Pt-Sn-PPh3 / Al2O3 (Pt6c) provided the highest initial conversion (23.6%) and gradually deactivated until reaching 11.5% after 3000 min at TOS. Regarding product selectivity, the alumina-based catalysts Pt-Sn-PPh3 / Al2O3 (Pt6c) and Pt-Sn-PPh3 / Li-Al2O3 (Pt7c) exhibited high propylene selectivity (approximately 99% or >99%).

[0293] Other catalysts tested in this invention (results not shown in Table 8(a)) namely the zeolite-based catalysts Pt-Sn-PPh3 / Na-ZSM-5 (Pt8c) and Pt-Sn-PPh3 / H-ZSM-5 (Pt9c) also exhibited high selectivity for propylene (70-90%). Therefore, the zeolite-based catalysts suggest selectivity for propylene similar to or higher than that of the Statoil catalyst (Pt8c; 70-85%) (Pt9c; 85-90%), and these selectivities are consistently higher than those of other commercial catalysts used for this reaction (see Table 8(b) below). Furthermore, the zeolite-based catalysts Pt-Sn-PPh3 / Na-ZSM-5 (Pt8c) and Pt-Sn-PPh3 / H-ZSM-5 (Pt9c) are sufficient to yield (C6)-aromatic compounds (e.g., benzene and substituted benzenes) (data not shown).

[0294] Ni-Sn / Al2O3 (Ni-Sn-PPh3 / Al2O3(Ni3)) provides propane selectivity comparable to that obtained using a Pt-Sn benchmark catalyst. To the best of the inventors' knowledge, this is the first example of a selective nickel-catalyzed propane dehydrogenation method. Replacing the expensive Pt system with the abundant and inexpensive Ni system is highly desirable for industrial applications. Example 6 clearly demonstrates that the alkane nODH using the catalyst composition of the above examples provides a high conversion index and very high propylene selectivity.

[0295] The selected initial conditions for non-oxidative dehydrogenation (n-ODH) of 2-butene, butane, and 2-butene / butane (1:1) are: temperature: 530 °C; pressure: 1 bar; and gas flow rates: 3 mL / min for 2-butene or 2-butene / butane (1 / 1), 21 mL / min for Ar, and 1 mL / min for H2.

[0296] The conversion and selectivity of butane or 2-butene / butane were determined by gas chromatography-TCD analysis of gas samples acquired at regular time intervals (every 14 min). Argon was used as an internal standard to determine the response factors for butane, 2-butene, and butadiene. The mathematical formulas used to determine the conversion and selectivity are as follows:

[0297]

[0298]

[0299] Table 8(b) below lists the results obtained by non-oxidative dehydrogenation of 2-butene and 2-butene / butane (1:1) dehydrogenation (BDH) using some of the catalyst compositions of the present invention. Comparative data with the benchmark Statoil catalyst (currently known as LINDE-Basf Statoil) are also included.

[0300] Table 8(b). 2-Butene and 2-Butene / Butane (BDH) catalyzed by Pt / Sn nanocatalysts

[0301]

[0302] In the non-oxidative dehydrogenation of 2-butene, Pt-Sn-PPh3 / Al2O3 (Pt6c) provided the highest initial conversion (10%), and it gradually deactivated until reaching 5.3% after 900 min at TOS. Regarding product selectivity, the alumina-based catalysts Pt-Sn-PPh3 / Al2O3 (Pt6c and Pt25) exhibited high butadiene selectivity (approximately 89%).

[0303] In the non-oxidative dehydrogenation of a 1:1 mixture of 2-butene and butane, Pt-Sn-PPh3 / Al2O3 (Pt6c) provided the highest initial conversion (4.7%), and the conversion remained stable throughout all experiments (4.7% after 900 min at TOS). Regarding product selectivity, the alumina-based catalyst Pt-Sn-PPh3 / Al2O3 (Pt6c) exhibited high butadiene selectivity (approximately 93%).

[0304] Table 9 below illustrates data on the conversion index and selectivity of existing industrial nODH for propane and butene / butane mixtures, as well as other parameters. For propane dehydrogenation (PDH), in general, the data obtained with the catalyst compositions of the present invention lead to the conclusion that higher selectivity (>99% for alumina-based catalysts) can be obtained, and the conversion percentage in commercial Pt-based catalysts is [not specified in the original text]. and Cr group Within the range of catalyst conversion percentage.

[0305] For 2-butene / butane and 2-butene dehydrogenation (BDH), in general, the data obtained with the catalyst compositions of the present invention lead to the conclusion that, even when using commercial Cr-based catalysts... The catalysts exhibit significantly higher selectivity (>99% for alumina-based catalysts).

[0306] Table 9. Comparative parameters of existing industrial methods for nODH of propane

[0307]

[0308] Example 7. Synthesis of catalyst compositions with different organophosphorus compounds

[0309] Sample description:

[0310] Seven catalyst samples of platinum (Pt)-tin (Sn) catalysts supported on alumina (Al2O3) were prepared with nominal Pt and Sn loadings of 2.0% w / w and 1.0% w / w, respectively (cat0-cat6). Catalysts cat1-cat5 were prepared by decomposing organometallic Pt and tin precursors at 100 °C and 3 bar of hydrogen in the presence of 0.2 equivalents of phosphorus ligands with six different functional groups for 40 h: (Cat1) monophosphine (PPh3) (disclosed in previous examples), (Cat2) diphosphine (dppm), (Cat3) monophosphite (tpd), (Cat4) monophosphite (tppt), (Cat5) secondary phosphine oxide (dpo), and (Cat6) tertiary phosphine oxide (topo). A blank Pt-Sn / Al2O3 catalyst sample (Cat0) was prepared in the absence of ligands.

[0311] The results are shown in Table 10, which illustrates several parameters and characteristics of the obtained catalyst:

[0312] Table 10

[0313]

[0314] TPP (PPh3): Triphenylphosphine. DPPM: 1,2-Bis(diphenylphosphine)methane. TPD: Tris(dimethylamino)phosphine. TPPT: Triphenyl phosphite. DPO: Diphenylphosphine oxide. TOPO: Trioctylphosphine oxide.

[0315] 1) Blank sample Cat0 compared to ligand samples Cat 1-5:

[0316] Overall, the blank sample showed an average diameter (1-2 nm) similar to that of the sample using ligands (i.e., using organophosphorus compounds). This is because the stabilizing effect of the alumina support was similar in all cases. This sample showed the highest Sn content (1.3% w / w) in the entire series. This is due to the effect of the ligand on Sn decomposition, i.e., the phosphorus ligand somehow reduced the decomposition rate of the Sn precursor.

[0317] 2) Monophosphine Cat1 (described in the preceding examples) compared to diphosphine Cat2:

[0318] The difference between monodentate and bidentate ligands lies in the stronger coordination of bidentate ligands with metals due to chelation. Using diphosphine ligands yields small PtSn nanoparticles, even below the detection limit of a disposable electron microscope in the inventors' laboratory (<1 nm). This is reasonable because the chelation of the ligands on the PtSn-NP surface provides greater stabilization. Bidentate ligands also provide catalysts with much lower Pt content, Sn content, and Sn / Pt molar ratio. Therefore, overall, these functional groups appear to affect the Pt decomposition rate, Sn decomposition rate, and average diameter of the PtSn nanoparticles, but are able to provide nanoparticles with diameters of approximately 1.0–2.0 nm.

[0319] 3) Monophosphine Cat1 (described in the preceding examples) compared to phosphorous amide Cat3 and phosphite Cat4:

[0320] The difference between these ligands lies in their coordination with the metal, due to their electronic properties: phosphine is a more basic donor compared to phosphorous amide and phosphite, while phosphorous amide and phosphite are more π-acceptors compared to phosphine. It appears that using phosphorous amide (Cat 3, 1.66 nm) and phosphite (Cat 4, 2.63 nm) produces larger Pt-Sn nanoparticles than those stabilized with monophosphine (Cat 1, 1.33 nm). The final Pt content using phosphorous amide (Cat 3, 1.0 wt%) and phosphite (Cat 4, 1.4 wt%) is significantly lower than that using monophosphine-stabilized Pt-Sn (Cat 1, 1.7 wt%), while the Sn content is similar in all three cases (i.e., approximately 1.04–1.11 wt%). Therefore, overall, these functional groups appear to affect the Pt decomposition rate and the average diameter of PtSn nanoparticles, but allow for the provision of nanoparticles with diameters of around 1.0–3.0 nm.

[0321] 4) Monophosphine Cat1 (described in the preceding examples) compared to secondary and tertiary phosphine oxides Cat5 and Cat6:

[0322] The difference between these ligands is that, relative to the previously described P(III) ligands, there are no lone pairs of electrons on the phosphorus (IV) material. Therefore, no or very soft interactions with either the metal precursor or the metal nanoparticles are expected. Using secondary phosphine oxide (Cat 5, 1.50 nm) and tertiary phosphine oxide (cat 6, 2.05 nm) appears to produce larger Pt-Sn nanoparticles than those stabilized with monophosphine (Cat 1, 1.33 nm). The final Pt content using secondary phosphine oxide (Cat 3, 0.6 wt%) and tertiary phosphine oxide (cat 6, 0.8 wt%) is significantly lower than that using monophosphine stabilized Pt-Sn (Cat 1, 1.7 wt%), while the final Sn content using secondary phosphine oxide (cat 3, 0.04 wt%) is significantly lower than that measured using tertiary phosphine oxide (cat 6, 1.05 wt%) and monophosphine (cat 1, 1.1 wt%). Therefore, in general, these functional groups appear to affect the Pt decomposition rate, Sn decomposition rate, and average diameter of PtSn nanoparticles, but allow for the provision of nanoparticles with diameters of around 1.0–3.0 nm.

[0323] Overall conclusion:

[0324] The use and properties of ligands applied as additives in the synthesis of Pt-Sn / Al2O3 catalysts affect the average diameter of nanoparticles and the Pt / Sn composition (i.e., affect the decomposition rate of Pt and Sn precursors), but enable the acquisition of catalysts with nanoparticles of very low diameter (1.0-3.0 nm).

[0325] Interestingly, the data from this embodiment also demonstrate that Pt-Sn / Al2O3 catalyst compositions with very low diameter (1.42 nm) nanoparticles can be obtained in a simple and clean manner using the method of the present invention (one-pot synthesis via an organometallic approach). This is presumably an advantage over other synthetic methods for these catalysts, such as those disclosed in EP0328507.

[0326] Example 8. Conversion of propane and selectivity for propylene in poisoned nODH reaction

[0327] Using the catalyst composition tSn(IV)-PPh3@Al2O3 of the present invention (in...) Figure 7 The abbreviation is PtSnIV-P, as described in Example 6 (Table 8(a)) in the presence of CO2 poison (hollow circles, PtSn). IV -P CO2) or the absence of the aforementioned poison (solid circle, PtSn) IV Propane dehydrogenation (PDH) was carried out under the condition of -P). The X-axis shows the continuous reaction time of the catalyst in hours.

[0328] like Figure 7 As shown in (A) the percentage of propane conversion (%) and (B) the percentage of selectivity for propylene (%), the conversion was achieved through CO2 poisoning. Figure 7 The hollow circles in (A) and (B) indicate improved catalyst stability, which means that the propane conversion is more stable over time compared to when there is no poisoning, while the selectivity for propylene is also improved.

[0329] Little is known about the catalytic performance of industrial catalysts in the presence of poisons. In fact, the presence of oxygen- or sulfur-containing molecules in the feed acts as inhibitors of Pt-Sn catalysts, disrupting their active sites and leading to catalyst deactivation and reduced selectivity for desired products. Low levels of water and oxygen-containing substances have been reported in propane feeds. At higher levels, these impurities can poison catalysts through various mechanisms. For example, they can deplete the chlorine necessary for the redispersion of sintered platinum in the catalyst and increase selectivity for carbon oxides. Although the presence of these substances is considered to negatively impact catalytic activity, their use in appropriate amounts can be beneficial to catalytic performance by reducing coke formation and increasing propylene yield. No studies on the poisoning of Pt-Sn catalysts in the presence of CO2 and sulfur have been reported in the literature.

[0330] Other aspects / implementations of the invention can be found in the following clauses:

[0331] Clause 1. A catalyst composition comprising:

[0332] (a) Metal nanoparticles; and

[0333] (b) A porous carrier having a surface region; wherein the nanoparticles (a) are adsorbed on the surface region of the porous carrier;

[0334] The nanoparticles (a) comprise: (i) one or more metal elements of Group 10 of the periodic table; (ii) one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; and (iii) one or more metal elements selected from tin (Sn), gallium (Ga) and indium (In).

[0335] Clause 2. The catalyst composition according to Clause 1, wherein at least one of the Group 10 elements in the nanoparticles is platinum (Pt) or nickel (Ni).

[0336] Clause 3. The catalyst composition according to any one of Clauses 1-2, wherein the tin (Sn), gallium (Ga) and indium (In) are in the nanoparticles (a) and on the surface region of the porous support (b).

[0337] Clause 4. The catalyst composition according to any one of Clauses 1-3 further comprises one or more co-catalysts.

[0338] Clause 5. The catalyst composition according to any one of Clauses 1-4, wherein the weight percentage of said one or more Group 10 metal elements is 0.2 to 5.0%, and the weight percentage of said one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides is 0.05 to 0.2%, all percentages relative to the total weight of the catalyst composition.

[0339] Clause 6. The catalyst composition according to Clause 5, wherein the Sn, Ga and In are present in a weight percentage of 0.15 to 1.0%, all percentages relative to the total weight of the catalyst composition.

[0340] Clause 7. The catalyst composition according to any one of Clauses 1-6, wherein the metal nanoparticles have a diameter of 1.0 to 15.0 nm, the diameter being measured by transmission electron microscopy (TEM).

[0341] Clause 8. The catalyst composition according to any one of Clauses 1-7, wherein the specific surface area (in m²) according to BET theory 2 The weight (in grams) ranges from 100 to 500 mg. 2 / g.

[0342] Clause 9. The catalyst composition according to any one of Clauses 1-8, wherein the molar ratio of the total amount of the one or more organic molecules to the one or more metal elements is 0.05-0.25:1.

[0343] Clause 10. The catalyst composition according to any one of Clauses 1-9, wherein the porous support is selected from alumina-based porous materials, silica-based porous materials, zeolite-based porous materials, aluminosilicate-based porous materials, and combinations thereof.

[0344] Clause 11. A method for preparing a catalyst composition as defined in any one of Clauses 1-10, said method comprising, in a one-pot step, decomposing one or more organometallic precursor compounds of one or more Group 10 elements and decomposing one or more organometallic precursor compounds of one or more metal elements selected from tin (Sn), gallium (Ga), and indium (In) in the presence of an organic solvent, a porous support, and one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; said one-pot decomposition is carried out in a hydrogen atmosphere at a temperature of 20°C to 100°C and 1.0 x 10⁻⁶ m³ / h. 5 Pa to 5.0 x 10 5 Perform tests under Pa pressure for 30 minutes to 70 hours.

[0345] Clause 12. The method according to Clause 11, wherein the one or more organometallic precursor compounds are added in an amount of 1 mole per 0.1-1.0 mole of the one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides.

[0346] Clause 13. A method for preparing one or more (C2-C4)-olefins and / or one or more (C6)-aromatic compounds, the method comprising non-oxidative dehydrogenation of (C2-C4)-alkanes and / or (C3-C4)-olefins, or non-oxidative dehydrogenation of (C2-C4)-alkanes and / or (C6)-cycloalkanes for the preparation of one or more (C6)-aromatic compounds, wherein the dehydrogenation is carried out using a step of contacting a feed stream comprising the (C2-C4)-alkanes and / or (C3-C4)-olefins or the (C2-C4)-alkanes and / or (C6)-cycloalkanes with a catalyst composition as defined in any one of Clauses 1-10 to obtain the one or more olefins and / or one or more aromatic compounds.

[0347] Clause 14. The method according to Clause 13, wherein the (C2-C4)-alkane is propane and the (C2-C4)-olefin is propylene.

[0348] Clause 15. Use of the catalyst composition defined in any of Clauses 1-10 for non-oxidative propane dehydrogenation (PDH), non-oxidative butane-butene dehydrogenation (BDH), and propane aromatization.

[0349] Citation List

[0350] Patent documents

[0351] -EP0328507A1 (Fina Research)

[0352] -US2005003960(STATOIL ASA)

[0353] Non-patent literature

[0354] -Sattler et al., 2014, Catalytic Dehydrogenation of Light Alkanes on Metals and Metal Oxides, Chemical Reviews, vol. no. 114, pp: 10613-10653

[0355] -Searles et al., 2018, Highly Productive Propane Dehydrogenation Catalyst Using Silica-Supported Ga-Pt Nanoparticles Generated from Single-Sites, Journal of American Chemical Society 140, pp.:11674-11679

[0356] -Wang et al., 2017, Colloidal Synthesis of Pt-In Bimetallic Nanoparticles for Propane Dehydrogenation, Can. J. Chem 1-29

[0357] -Lomelí-Rosales et al., 2019, A general one-pot methodology for the preparation of mono and bimetallic nanoparticles supported on carbon nanotubes: application in the semi-hydrogenation of alkynes and acetylene, Chem. Eur. J. 10.1002 / chem.201901041

[0358] -Humlot and Basset et al., (1998), Surface organometallic chemistry on metals: Stable precursors for surface alloying obtained by stepwise hydrogenolysis of Sn(n-C4H9)4 on silica-supported platinum particles Formation of Sn(n-C4H9)n fragments (Surface Organometallic Chemistry on Metals: Formation of a Stable) Sn(n-C4H9)n Fragment as a Precursor of Surface Alloy Obtained by StepwiseHydrogenolysis of Sn(n-C4H9)4on a Platinum Particle Supported on Silica), J.Am.Chem.Soc.120,1,137-146

[0359] - et al., (2008), Methanol to gasoline over zeolite H-ZSM-5: Improved catalyst performance by treatment with NaOH, Applied Catalysts A: General 345, 43-50

[0360] -Rouge et al., (2019), A smarter approach to catalysts by design: Combining surface organometallic chemistry on oxide and metal gives selective catalysts for dehydrogenation of 2,3-dimethylbuthane, Molecular Catalysis 471, 21-26

Claims

1. A catalyst composition comprising: (a) Metal nanoparticles; and (b) A porous carrier having a surface region; wherein the nanoparticles (a) are adsorbed on the surface region of the porous carrier; The nanoparticles (a) comprise: (i) one or more metal elements of Group 10 of the periodic table; (ii) one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; and (iii) one or more metal elements selected from tin (Sn), gallium (Ga), and indium (In); The molar ratio of one or more organic molecules to one or more metal elements is 0.05-0.25 :

1.

2. The catalyst composition according to claim 1, wherein the organophosphorus compound is a compound of formula (I). (I)， Where n is an integer of 0 or 1, and when n is 1, Z is oxygen; and where R1, R2, and R3 are each independently selected from: - (C1-C 10 (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl, or (C1-C4)-alkanoyloxy are all considered to be straight-chain or branched. - Optionally substituted phenyl; - A group represented by -CP(R4)(R5), wherein R4 and R5 are independently selected from hydrogen, phenyl or optionally substituted phenyl; - A group represented by -N(R6)(R7), wherein R6 and R7 are independently selected from (C1-C2). 10 (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl, or (C1-C4)-alkanoyloxy, all of which are considered to be straight-chain or branched; or - Group -O-R8, where R8 is an optionally substituted C6-aromatic ring.

3. The catalyst composition according to claim 2, wherein the organophosphorus compound is a compound of formula (I), which is a phosphine, wherein n is an integer of 0 or 1, and when n is 1, Z is oxygen; and wherein R1, R2 and R3 are each independently selected from: - (C1-C 10 (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl, or (C1-C4)-alkanoyloxy are all considered to be straight-chain or branched. - Optionally substituted phenyl; - A group represented by -CP(R4)(R5), wherein R4 and R5 are independently selected from hydrogen, phenyl, or optionally substituted phenyl groups; or - A group represented by -N(R6)(R7), wherein R6 and R7 are independently selected from (C1-C2). 10 (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl or (C1-C4)-alkanoyloxy, are all considered to be straight-chain or branched.

4. The catalyst composition according to claim 1, wherein the organophosphorus compound is selected from triphenylphosphine, 1,2-bis(diphenylphosphine)methane, tris(dimethylamino)phosphine, diphenylphosphine oxide, or trioctylphosphine oxide.

5. The catalyst composition according to claim 2, wherein the organophosphorus compound is a compound of formula (I), which is a phosphite, wherein n is 0, and wherein R1, R2 and R3 are each -O-R8 groups, wherein R8 is an optionally substituted C6-aromatic ring.

6. The catalyst composition according to claim 5, wherein the compound of formula (I) is triphenyl phosphite.

7. The catalyst composition according to claim 1, wherein at least one Group 10 element in the nanoparticles is platinum (Pt) or nickel (Ni).

8. The catalyst composition according to claim 1, wherein the tin Sn, gallium Ga and indium In are in the nanoparticles (a) and on the surface region of the porous support (b).

9. The catalyst composition according to claim 1, further comprising one or more co-catalysts.

10. The catalyst composition of claim 1, wherein the weight percentage of the one or more Group 10 metal elements is 0.2 to 5.0%, and the weight percentage of the one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides is 0.05 to 0.2%, all percentages relative to the total weight of the catalyst composition.

11. The catalyst composition of claim 10, wherein the Sn, Ga and In are present in a weight percentage of 0.15 to 1.0%, all percentages being relative to the total weight of the catalyst composition.

12. The catalyst composition of claim 1, wherein the metal nanoparticles have a diameter of 0.5 to 15 nm, the diameter being measured by transmission electron microscopy.

13. The catalyst composition of claim 12, wherein the metal nanoparticles have a diameter of 1.0 to 15.0 nm, the diameter being measured by transmission electron microscopy.

14. The catalyst composition according to claim 1, wherein the specific surface area according to BET theory is 100 to 500 m². 2 / g.

15. The catalyst composition according to claim 1, wherein the porous support is selected from porous materials based on alumina, porous materials based on silica, porous materials based on aluminosilicates, or combinations thereof.

16. A method for preparing the catalyst composition of claim 1, the method comprising, in a one-pot process, decomposing one or more organometallic precursor compounds of one or more Group 10 elements and decomposing one or more organometallic precursor compounds of one or more metal elements selected from tin (Sn), gallium (Ga), and indium (In) in the presence of an organic solvent, a porous support, and one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides; said one-pot decomposition is carried out in a hydrogen atmosphere at a temperature of 20°C to 100°C and 1.0 x 10⁻⁶ ppm. 5 Pa to 5.0 x 10 5 Perform tests under Pa pressure for 30 minutes to 70 hours.

17. The method of claim 16, wherein the one or more organometallic precursor compounds are added in an amount of 1 mole per 0.1-1.0 mole of the one or more organic molecules selected from organophosphorus compounds and N-heterocyclic carbides.

18. The method according to claim 16, wherein the organophosphorus compound is a compound of formula (I), (I)， Where n is an integer of 0 or 1, and when n is 1, Z is oxygen; and where R1, R2, and R3 are each independently selected from: - (C1-C 10 (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl, or (C1-C4)-alkanoyloxy are all considered to be straight-chain or branched. - Optionally substituted phenyl; - A group represented by -CP(R4)(R5), wherein R4 and R5 are independently selected from hydrogen, phenyl or optionally substituted phenyl; - A group represented by -N(R6)(R7), wherein R6 and R7 are independently selected from (C1-C2). 10 (C1-C4)-alkyl, (C1-C4)-alkoxy, (C1-C4)-alkanoyl, (C1-C4)-alkoxycarbonyl, or (C1-C4)-alkanoyloxy, all of which are considered to be straight-chain or branched; or - Group -O-R8, where R8 is an optionally substituted C6-aromatic ring.

19. A method for preparing one or more (C2-C4)-olefins, the method comprising non-oxidative dehydrogenation of (C2-C4)-alkanes and / or (C3-C4)-olefins, said dehydrogenation being carried out by contacting a feed stream containing said (C2-C4)-alkanes and / or (C3-C4)-olefins with the catalyst composition of claim 1 to obtain said one or more olefins.

20. A method for preparing one or more (C6)-aromatic compounds, the method being a non-oxidative dehydrogenation of (C2-C4)-alkanes and / or a non-oxidative dehydrogenation of (C6)-cycloalkane compounds, the dehydrogenation being carried out by contacting a feed stream containing the (C2-C4)-alkanes and / or (C6)-cycloalkane compounds with the catalyst composition of claim 1 to obtain the one or more aromatic compounds.

21. The method according to claim 19, wherein the (C2-C4)-alkane is propane, and the (C2-C4)-olefin is propylene.

22. A method using the catalyst composition of claim 1 for non-oxidized propane dehydrogenation, non-oxidized butane-butene dehydrogenation, or propane aromatization.

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