Electrocatalytic preparation method for synthesizing hydrogen by coupling hydrogen storage liquid formic acid

Abstract

The invention discloses an electro-catalysis preparation method for synthesizing hydrogen by coupling hydrogen storage liquid formic acid, and belongs to the technical field of electro-catalysis. The method comprises the following steps: constructing an electro-catalysis system comprising an electro-catalyst and an electrolyte; and after the reaction is finished, separating and purifying to obtain formic acid and hydrogen. By adopting the cathode and anode coupling method, the two ends of the cathode and the anode are fully utilized, on one hand, glycerol is continuously oxidized at the anode end to break the carbon-carbon bond to finally generate hydrogen storage liquid formic acid, and on the other hand, the cathode end is fully utilized to generate hydrogen evolution reaction to obtain green energy hydrogen; the effective utilization of electricity is improved; and hydrogen storage liquid formic acid and hydrogen are synthesized in a coupling manner.

Description

Technical Field

[0001] This invention relates to the field of electrocatalysis technology, and in particular to an electrocatalytic preparation method for the synthesis of hydrogen from hydrogen-storing liquid formic acid. Background Technology

[0002] Formates are key platform chemicals in pharmaceuticals, agriculture, and energy storage, and are important hydrogen storage liquids, typically produced via the thermocatalytic oxidation of glycerol. However, this route operates under high temperature and pressure conditions, relies on an external oxidant, and generates numerous byproducts. The electrochemical glycerol oxidation reaction (GOR) offers a potential alternative for the production of formates using renewable electricity under environmental conditions. This electrocatalytic method not only upgrades glycerol to formate at the anode but also generates high-purity H2 at the cathode. This synergy improves energy efficiency and facilitates scalable chemical synthesis with carbon reduction targets.

[0003] The electrocatalytic oxidation of glycerol to formate involves sequential dehydrogenation and C / C bond cleavage. Formate yield and selectivity are primarily hampered by the adsorption and activation of glycerol and hydroxyl (*OH) species. Noble metals, including Pt, Pd, and Au, have been extensively studied in GOR due to their high activity and low overpotential. However, their practical application is limited by high cost and the tendency to form C3 products. Transition metal nickel-based catalysts have attracted increasing attention in electrocatalytic GOR due to their excellent C / C bond cleavage ability, economic advantages, and structural tunability. However, nickel-based catalysts face challenges such as weak adsorption capacity for glycerol and hydroxyl species, moderate conductivity, and poor stability. Recently, nickel-based alloy catalysts have provided an effective strategy to address these challenges. Cu-doped NiCo alloy catalysts exhibit high GOR activity, where Ni... 3+ -OOH and Co 3+ -OOH species are active species, and Cu doping promotes the coupling of surface *O with reactive intermediates. Ni and Co single-atom sites synergistically optimize the electronic structure of Co active sites with NiCo alloys, lowering the energy barrier for *OH-mediated C / C bond breaking and dehydrogenation. High-entropy NiCoFeRuRe alloys accelerate the coupling of high-valence M... 3+ The formation of sites improves formate production and catalyst durability. Despite these advancements, formate production remains low and requires further improvement.

[0004] In summary, the rational design of catalysts and processes to achieve synergistic enhancement of hydroxyl / glycerol adsorption and promote dehydrogenation and C / C bond breaking kinetics is of great significance in this field. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide an electrocatalytic preparation method for the synthesis of hydrogen from hydrogen-storing liquid formic acid, wherein a catalyst is synthesized on a conductive support by electrochemical deposition and used for the electrocatalytic oxidation of glycerol to formic acid and the coupling synthesis of hydrogen.

[0006] To achieve the above objectives, the present invention provides an electrocatalytic preparation method for hydrogen gas by coupling hydrogen storage liquid formic acid with hydrogen synthesis, comprising the following steps: An electrocatalytic system comprising an electrocatalyst and an electrolyte was constructed; an oxidation voltage was applied to initiate the reaction; after the reaction was completed, formic acid and hydrogen were separated and purified. The electrocatalytic system comprises a three-electrode system consisting of a working electrode, a counter electrode, and a reference electrode; wherein the working electrode comprises an electrocatalyst; the electrocatalyst is made of a transition metal supported on a conductive support; wherein the transition metal includes at least one of nickel, iron, cobalt, manganese, copper, and vanadium; The electrolyte comprises a phase-separated anolyte and a catholyte; wherein the anolyte comprises an alkaline solution containing glycerol, and the catholyte comprises an alkaline solution.

[0007] Preferably, the oxidation voltage is 1.4~1.9 V vs. RHE, and the oxidation voltage duration is 0.5~2 h.

[0008] Preferably, the counter electrode includes one of a platinum sheet electrode, a titanium sheet electrode, a gold sheet electrode, and a graphite electrode.

[0009] Preferably, the reference electrode is an Hg / HgO electrode.

[0010] More preferably, the internal filling solution of the Hg / HgO electrode is a 0.8~1.2 M potassium hydroxide solution.

[0011] Preferably, the conductive carrier includes one or more of the following: nickel foam, copper foam, iron foam, carbon paper, and carbon felt.

[0012] More preferably, the conductive carrier is nickel foam.

[0013] Preferably, the transition metal includes two or more of nickel, iron, cobalt, manganese, copper, and vanadium.

[0014] More preferably, the transition metal is nickel or iron.

[0015] Preferably, the preparation method of the electrocatalyst includes the following steps: preparation using a three-electrode system, the three-electrode system including a working electrode, a counter electrode and a reference electrode, the working electrode being made of a conductive support; using a transition metal salt as a transition metal source, and an aqueous solution of the transition metal source as an electrochemical deposition solution, placing the working electrode in the electrochemical deposition solution, applying a voltage of -0.6 to -1.5 V vs. RHE for electrochemical deposition, the deposition time lasting 30 to 90 s; after the electrochemical deposition is completed, removing the working electrode, washing and drying it to obtain an integrated electrocatalyst.

[0016] More preferably, the transition metal source in the electrochemical deposition solution includes at least one of nickel nitrate, iron nitrate, cobalt nitrate, copper nitrate, and vanadium nitrate.

[0017] More preferably, the concentration of the transition metal source in the electrochemical deposition solution is 10~90 mM.

[0018] Preferably, the anolyte is a mixed solution formed by a potassium hydroxide solution with a concentration of 0.5~2 M and a glycerol solution with a concentration of 0.05~1 M.

[0019] Preferably, the cathode electrolyte is a potassium hydroxide solution with a concentration of 0.5~2 M.

[0020] Preferably, the anolyte is stirred at a rate of 600-1000 rpm during the reaction.

[0021] Preferably, the anolyte and the catholyte are separated by a proton exchange membrane made of perfluorosulfonic acid resin.

[0022] Based on the above technical solutions, the design concept and principle of this invention are as follows: Existing technologies employ methods such as alloying, heterojunctions, and even noble metals to construct novel electrocatalysts to improve formic acid yield and hydrogen evolution performance at the cathode. Compared to these methods that utilize more complex electrocatalysts to enhance formic acid yield, this invention designs a catalyst synthesized on a conductive support using electrochemical deposition. This catalyst is then used for the electrocatalytic oxidation of glycerol to formic acid, coupled with hydrogen synthesis. This significantly improves formic acid yield and hydrogen evolution performance during the catalytic process, while reducing the cost of the required electrocatalyst, saving raw material costs, and facilitating industrial applications.

[0023] Furthermore, this invention designs a method to oxidize glycerol by applying an oxidation potential, ultimately yielding hydrogen-storing liquid formic acid, which is then coupled to the cathode for the synthesis of hydrogen, an important green energy source. On one hand, the yield of formic acid at the anode is further improved; on the other hand, electrical energy is fully utilized, and the cathode is also fully utilized. The catalyst synthesis method constructed by this strategy is simple and exhibits a high production rate during the electrochemical preparation of glycerol, achieving superior results compared to most currently reported catalysts and systems.

[0024] Therefore, this invention utilizes the anode-cathode coupling method to fully leverage both ends of the anode and cathode. On the one hand, glycerol is continuously oxidized at the anode to break its carbon-carbon bonds and ultimately generate hydrogen-storing liquid formic acid. On the other hand, the cathode is fully utilized to induce a hydrogen evolution reaction, yielding green energy hydrogen. Through the combined effect, the anode and cathode are fully utilized, improving the efficient use of electricity and coupling the preparation of hydrogen-storing liquid formic acid and hydrogen.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention provides an electrocatalytic method for the synthesis of hydrogen from hydrogen-storing liquid formic acid. The catalyst used is simple to prepare and has a low cost. The method has high formic acid yield and high hydrogen evolution performance, and has excellent prospects for industrial-scale application. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the synthesis of the electrocatalyst in Example 1; Figure 2 This is a schematic diagram illustrating the reaction principle of the electrocatalytic preparation method in Example 1; Figure 3 The X-ray diffraction results are for the electrocatalyst in Example 1; Figure 4 The results are obtained from transmission electron microscopy of the electrocatalyst in Example 1; Figure 5 This is a comparison chart of the linear scan voltammetric performance of the experimental group and the control group constructed using the method in Example 1; Figure 6 This is a comparison chart of the electrocatalytic performance of formic acid preparation using anolytes with different glycerol concentrations constructed according to the method of Example 1; Figure 7 The graph shows a comparison of the performance of the NiFe LDH@NF electrocatalyst constructed using the method in Example 1 in the electrocatalytic oxidation of glycerol to formic acid at different potentials in a mixed solution of 0.1 M glycerol and 1 M potassium hydroxide. Figure 8 The graph shows a comparison of the performance of the Fe LH@NF electrocatalyst constructed using the method in Example 8 in the electrocatalytic oxidation of glycerol to formic acid at different potentials in a mixed solution of 0.1 M glycerol and 1 M potassium hydroxide. Figure 9 The graph shows a comparison of the performance of the Ni LH@NF electrocatalyst constructed using the method in Example 10 in the electrocatalytic oxidation of glycerol to formic acid at different potentials in a mixed solution of 0.1 M glycerol and 1 M potassium hydroxide. Figure 10 The results are from performance testing of the electrocatalyst of Example 13 using the electrochemical testing method of Example 1. Figure 11 This is a comparison of the rate of glycerol-to-formic acid production by the NiFe LDH@NF constructed using the method of Example 1 with currently reported catalysts; Figure 12 This is a comparison of the linear sweep voltammetric performance of the experimental group and the control group in 1 M potassium hydroxide, constructed using the method of Example 1. Figure 13 This is a comparison of the electrocatalytic hydrogen evolution performance of the NiFe LDH@NF electrocatalyst constructed using the method in Example 1 at different potentials in 1 M potassium hydroxide solution; Figure 14 This is a schematic diagram of the membrane electrode constructed using the electrocatalyst in Example 1; Figure 15 The results show the stability test results of the membrane electrode constructed using the electrocatalyst in Example 1 at the glycerol oxidation end; Figure 16 The results show the stability test results of the membrane electrode constructed using the electrocatalyst in Example 1 at the hydrogen evolution reduction end. Detailed Implementation

[0027] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0028] Example 1 This embodiment provides an electrocatalytic method for the synthesis of hydrogen from hydrogen-storing liquid formic acid. The schematic diagram of the electrocatalyst synthesis and the reaction principle are shown below. Figure 1 , Figure 2 As shown, the performance of this method is characterized synchronously, and the steps are as follows: Preparation of the electrocatalyst: NiFe LDH@NF was synthesized using an electrochemical deposition method. For electrodeposition, a three-electrode system was used for synthesis, with a 1×2 cm⁻¹ electrode spacing. -2 A platinum sheet was used as the counter electrode, an Ag / AgCl electrode as the reference electrode, and treated nickel foam as the working electrode. The electrodeposition solution was Ni(NO3)2·6H2O (60 mmol / L). -1) and Fe(NO3)3·9H2O (20 mmol L -1 A mixed solution (50 ml) was prepared, and after passing nitrogen gas through the electrodeposition chamber for 30 minutes (to remove the influence of carbon dioxide), electrodeposition was performed using a constant voltage method. The electrodeposition voltage was 1.0 V vs. Ag / AgCl, and the time was 60 seconds. After electrodeposition, the nickel foam was rinsed three times with ultrapure water and then placed in a vacuum oven at 40°C to dry overnight.

[0029] Construction of a three-electrode system: All tests on the electrochemical oxidation of glycerol to formic acid coupled with hydrogen production were conducted in a three-electrode system. The constructed three-electrode electrolytic cell was a standard 30 mL H-type electrolytic cell, with the anode and cathode separated by a Nafion 117 proton exchange membrane made of perfluorosulfonic acid resin. For electrolyte filling, the cathode electrolyte was 25 mL of a 1 M potassium hydroxide solution, and the anolyte was a 25 mL mixture of 1 M potassium hydroxide and 0.1 M glycerol. For all three electrodes, the actual immersion area of ​​the cathode electrode was 1 × 1 cm². -2 The area is 1×2 cm -2 The platinum sheet electrode is used as the counter electrode, and the actual immersion area of ​​the anode electrode is 1 × 1 cm². -2 The area is 1×2cm -2 An electrocatalyst was used as the working electrode, and an Hg / HgO electrode filled with 1 M potassium hydroxide was used as the reference electrode.

[0030] Electrochemical Testing: Linear sweep voltammetry (LSV) was performed on all materials after assembling the H-type electrolytic cell according to the three-electrode construction method described above. The scanning voltage range was 0.5–2.5 V vs. RHE, and the scan rate was 5 mV / s. -1 The cathode electrolyte was filled with a 1 M potassium hydroxide solution, and the anolyte was filled with a mixed solution of 1 M potassium hydroxide and 0.1 M glycerol. Potentially constant polarization (it) was performed using data obtained from linear sweep voltammetry curves. Voltages of 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9 V vs. RHE were selected for constant voltage polarization tests. The specific test method was as follows: polarization was performed at a constant voltage for 3600 seconds, and each voltage group was repeated three times to obtain error bars. The membrane electrode assembly (MEA) stability test consisted of a cathode and anode composed of two titanium sheets with built-in flow fields. The entire membrane electrode contained a catalyst (actual reaction area of ​​1 cm²). 2The cathode and anode are separated by two gas diffusion electrodes and a proton exchange membrane Nafion 117. At the anode, the electrolyte in the flow channel is a mixed solution of 1 M KOH and 0.1 M GLY, and the electrolyte in the cathode flow channel is 1 M KOH. The stability of the membrane electrode was tested at room temperature and pressure.

[0031] Product detection: Shimadzu liquid chromatography-mass spectrometry (LC-MS) with a sugar column was used for product detection. The mobile phase was 0.5 mM sulfuric acid solution, and the flow rate was 0.2 mL / min. -1 The column oven temperature was 65℃, and the product was analyzed using a differential detector.

[0032] Example 2 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis by coupling hydrogen storage liquid formic acid. The difference between this embodiment and Embodiment 1 is that the oxidation potential applied in the preparation step of this embodiment is 1.4 V vs. RHE.

[0033] Example 3 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis by coupling hydrogen storage liquid formic acid. The difference between this embodiment and Embodiment 2 is that the oxidation potential applied in the preparation step of this embodiment is 1.5 V vs. RHE.

[0034] Example 4 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis from hydrogen-storing liquid formic acid. The difference between this embodiment and Embodiment 2 is that the oxidation potential applied in the preparation steps of this embodiment is 1.6 V vs. RHE.

[0035] Example 5 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis from hydrogen-storing liquid formic acid. The difference between this embodiment and Embodiment 2 is that the oxidation potential applied in the preparation steps of this embodiment is 1.7 V vs. RHE.

[0036] Example 6 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis by coupling hydrogen storage liquid formic acid. The difference between this embodiment and Embodiment 2 is that the oxidation potential applied in the preparation step of this embodiment is 1.8 V vs. RHE.

[0037] Example 7 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis by coupling hydrogen storage liquid formic acid. The difference between this embodiment and Embodiment 2 is that the oxidation potential applied in the preparation step of this embodiment is 1.9 V vs. RHE.

[0038] Example 8 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis by coupling hydrogen storage liquid formic acid. The difference between this embodiment and Embodiment 1 is that only the same type of iron salt is used in the electrodeposition process.

[0039] Example 9 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis from hydrogen-storing liquid formic acid. The difference between this embodiment and Embodiment 2 is that the electrocatalyst used in this embodiment is the same as that in Embodiment 8. In the main steps of formic acid preparation in this embodiment, six sets of settings with oxidation potentials of 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9 V vs. RHE were used for the corresponding preparation.

[0040] Example 10 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis by coupling hydrogen storage liquid formic acid. The difference between this embodiment and Embodiment 1 is that only the same type of nickel salt is used in the electrodeposition process.

[0041] Example 11 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis from hydrogen-storing liquid formic acid. The difference between this embodiment and Embodiment 2 is that the electrocatalyst used in this embodiment is the same as that in Embodiment 10. In the main steps of formic acid preparation in this embodiment, six sets of settings with oxidation potentials of 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9 V vs. RHE were used for the corresponding preparation.

[0042] Example 12 This embodiment provides a method for preparing an electrocatalyst. The difference between this embodiment and Embodiment 1 is that the electrocatalyst is pre-treated nickel foam. The pre-treatment method for the nickel foam is as follows: the nickel foam is accurately cut into 1×2cm pieces. -2 The nickel foam was shaped into a rectangular pattern and ultrasonically cleaned in acetone solution to remove organic impurities from the surface. Subsequently, it was ultrasonically cleaned in 3 M hydrochloric acid solution for 30 minutes to remove the oxide layer on the surface of the nickel foam. The above operation was repeated three times and then placed in a vacuum oven at 40°C overnight to dry.

[0043] Example 13 This embodiment provides an electrocatalytic preparation method for hydrogen synthesis from hydrogen-storing liquid formic acid. The difference between this embodiment and Embodiment 2 is that the electrocatalyst used in this embodiment is the catalyst described in Embodiment 12. In the main steps of formic acid preparation in this embodiment, six sets of settings with oxidation potentials of 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9 V vs. RHE were used for the corresponding preparation.

[0044] Based on the above embodiments, the performance of the present invention was tested and verified: (1) X-ray diffraction of the electrocatalyst in the method of Example 1 was performed using a Rigaku SmartLab X-ray powder diffractometer at 3~80°. The results are as follows: Figure 3 As shown.

[0045] (2) Morphological tests were performed on Examples 1, 8, and 10 using a JEOL 2100PLUS transmission electron microscope (Japan). The results are as follows: Figure 4 As shown.

[0046] (3) The three-electrode system constructed in Example 1 was used as the experimental group (cathode electrolyte was 1M KOH, anode electrolyte was 1M KOH + 0.1M GLY), the reaction voltage range was set to 0.5~2.5 V vs. RHE, and the scan rate was 5 mVs. -1 The linear scan voltammetry curves were tested. Examples 8, 10, and 12 were tested using the same method, and the resulting performance comparison graphs of the linear scan ends are shown below. Figure 5 As shown.

[0047] (4) The standard curves of the reactants and products were first tested using a Shimadzu liquid chromatograph. The reaction time of the constant voltage electrocatalytic oxidation was controlled to be 1 h. The selectivity and yield of formic acid in Example 1 were detected by the external standard method. The results are as follows: Figure 7 As shown; the selectivity and yield of formic acid in Example 8 were tested, and the results are as follows. Figure 8 As shown; the selectivity and yield of formic acid in Example 10 were tested, and the results are as follows. Figure 9 As shown; the selectivity and yield of formic acid in Example 12 were tested, and the results are as follows. Figure 10 As shown.

[0048] (5) The catalyst prepared by the method in Example 1 is prepared according to... Figure 13 The membrane electrode was constructed using the structural model described in Example 1. Electrocatalysts containing the catalysts from Example 1 were placed at both the positive and negative ends of the membrane electrode, with each electrocatalyst having a reaction area of ​​1 × 1 cm². -2 The electrodes are separated by a Nafion 117 proton exchange membrane made of perfluorosulfonic acid resin. A mixed solution of 1 M potassium hydroxide solution and 0.1 M glycerol solution is introduced as the electrolyte at the oxidizing end of the electrode, while a 1 M potassium hydroxide solution is introduced at the reducing end. Both solutions are pumped in at a flow rate of 10 mL / min. -1 Stability tests were conducted by applying an oxidation current of 100 mA, and the results are as follows: Figure 14 As shown.

[0049] The following combination Figures 5-10 as well as Figure 6The experimental results provided provide a detailed explanation of this application: Reference Figure 3 The structure of the electrocatalyst synthesized in Example 1 was analyzed using a Rigaku SmartLab X-ray powder diffractometer (Japan). The results showed that the electrocatalyst synthesized in Example 1 had characteristic diffraction peaks of NiFeLDH and elemental nickel, verifying the successful synthesis of the electrocatalyst.

[0050] Reference Figure 4 The morphology and structure of the electrocatalysts synthesized in Examples 1, 8 and 10 were analyzed using a JEOL 2100PLUS transmission electron microscope. The results showed that the electrocatalysts synthesized in Examples 1, 8 and 10 had the inherent morphology of layered hydroxides, i.e., plate-like, which indirectly verified the successful synthesis of the electrocatalysts.

[0051] Reference Figure 5 The results showed that linear sweep voltammetry was performed on four groups of electrocatalysts, namely NiFe LDH@NF, Fe LH@NF, Ni LH@NF and NF. The results indicated that NiFe LDH@NF had a high current density at any voltage, which suggests that NiFe LDH@NF may have the best electrocatalytic ability to oxidize glycerol to formic acid.

[0052] refer to Figure 6 The performance of NiFe LDH@NF at different concentrations was tested at 1.8 V vs. RHE. The results showed that when the concentration of glycerol in the anolyte was 0.1 M, it exhibited the best formic acid selectivity and yield, namely 91.62% and 67.75 mol m³, respectively. -2 h -1 The reduced performance due to high glycerol concentrations may be due to the production of a large amount of intermediate products.

[0053] refer to Figure 7 The electrocatalyst of Example 1 was tested using the electrochemical testing method described in Example 1. The results showed that, under six voltage conditions, the optimal formic acid selectivity (91.62%) and optimal formic acid yield (67.75 mol m³) were achieved at a voltage of 1.8 V vs. RHE. -2 h -1 .

[0054] refer to Figure 8 The electrocatalyst of Example 8 was tested using the electrochemical testing method described in Example 1. The results showed that, under six voltage conditions, the optimal formic acid selectivity (82.61%) and optimal formic acid yield (34.78 mol m) were obtained at a voltage of 1.8 V vs. RHE.-2 h -1 .

[0055] refer to Figure 9 The electrocatalyst of Example 1 was tested using the electrochemical testing method described in Example 10. The results showed that, under six voltage conditions, the optimal formic acid selectivity (74.61%) and the optimal formic acid yield (19.98 mol m³) were obtained at a voltage of 1.8 V vs. RHE. -2 h -1 . refer to Figure 10 The electrocatalyst of Example 13 was tested using the electrochemical testing method described in Example 1. The results showed that, under six voltage conditions, the optimal formic acid selectivity (69.82%) and optimal formic acid yield (14.38 mol m³) were obtained at a voltage of 1.8 V vs. RHE. -2 h -1 .

[0056] comprehensive Figures 8-14 The results indicate that the Fe-O-Ni bridging sites in NiFe LDH@NF enhance the electrochemical oxidation of glycerol to formic acid. These bridging sites may promote electron transfer between nickel and iron, thus promoting the production of Ni... 3+ The redox reaction between glycerol and hydroxyl groups may enhance the adsorption and activation between hydroxyl groups and glycerol, thereby improving the kinetics of continuous dehydrogenation and carbon-carbon bond breaking of glycerol. Furthermore, compared with other catalysts, the catalyst in this example exhibits a superior formic acid production rate.

[0057] refer to Figure 12 The results showed that the catalyst synthesized by the method in Example 1 was subjected to linear sweep voltammetry testing, and the specific testing method was as shown in Example 1. The only difference was that the electrolytes at both the anode and cathode were 1 M potassium hydroxide solutions. The results showed that NiFe LDH@NF had a high current density at any voltage, which indicates that NiFeLDH@NF may have the best electrocatalytic hydrogen evolution ability.

[0058] refer to Figure 13 The results showed that the catalyst synthesized by the method in Example 1 underwent a constant voltage hydrogen evolution performance test, with the specific test method as shown in Example 1. The only difference was that the electrolytes at both the anode and cathode were 1 M potassium hydroxide solutions. The results indicated that NiFe LDH@NF exhibited the best hydrogen evolution Faraday efficiency of 98.66% at -0.4 V vs. RHE, with a hydrogen yield of 2.12 mol m³. -2 h -1 This indicates that NiFe LDH@NF has excellent electrocatalytic hydrogen evolution ability.

[0059] Reference Figure 15 The results showed that when the electrocatalyst synthesized by the method of Example 1 was applied to the membrane electrode, the glycerol oxidation stability was tested by the constant current test method with a current of 100 mA. The membrane electrode remained stable after 220 h of operation, indicating that the electrocatalyst synthesized by the method of Example 1 of this application has excellent membrane electrode glycerol oxidation stability, and also verifying the feasibility of industrial application.

[0060] Reference Figure 16 The results showed that when the electrocatalyst synthesized by the method of Example 1 was applied to the membrane electrode, the hydrogen evolution stability was tested by the constant current test method with a current of -100 mA. The membrane electrode remained stable after 30 h of operation, indicating that the electrocatalyst synthesized by the method of Example 1 of this application has excellent membrane electrode hydrogen evolution stability, and also verifying the feasibility of industrial application.

[0061] In summary, this invention provides an electrocatalytic method for the synthesis of hydrogen from hydrogen-storing liquid formic acid coupled with chemical deposition. The method employs electrochemical deposition to synthesize a catalyst on a conductive support, which is then used for the electrocatalytic oxidation of glycerol to formic acid, coupled with hydrogen synthesis. This electrodeposition strategy is simple and uses inexpensive raw materials, and its formic acid generation performance surpasses that of previously reported literature. Furthermore, industrial simulations based on membrane electrode assemblies demonstrate the excellent industrial feasibility of this strategy and its broad application prospects.

[0062] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. An electrocatalytic method for the synthesis of hydrogen from hydrogen-storing liquid formic acid, characterized in that, Includes the following steps: An electrocatalytic system comprising an electrocatalyst and an electrolyte was constructed; an oxidation voltage was applied to initiate the reaction; after the reaction was completed, formic acid and hydrogen were separated and purified. The electrocatalytic system comprises a three-electrode system consisting of a working electrode, a counter electrode, and a reference electrode; wherein the working electrode comprises an electrocatalyst; the electrocatalyst is made of a transition metal supported on a conductive support; wherein the transition metal includes at least one of nickel, iron, cobalt, manganese, copper, and vanadium; The electrolyte comprises a phase-separated anolyte and a catholyte; wherein the anolyte comprises an alkaline solution containing glycerol, and the catholyte comprises an alkaline solution.

2. The electrocatalytic preparation method for hydrogen synthesis from hydrogen-storing liquid formic acid according to claim 1, characterized in that: The oxidation voltage is 1.4~1.9 V vs. RHE, and the oxidation voltage duration is 0.5~2 h.

3. The electrocatalytic method for hydrogen production from hydrogen storage liquid formic acid coupling synthesis according to claim 1, characterized in that: The counter electrode includes one of a platinum sheet electrode, a titanium sheet electrode, a gold sheet electrode, and a graphite electrode; the reference electrode is an Hg / HgO electrode.

4. The electrocatalytic method for hydrogen production from hydrogen storage liquid formic acid coupling synthesis according to claim 1, characterized in that: The conductive carrier includes one or more of nickel foam, copper foam, iron foam, carbon paper, and carbon felt; the transition metal includes two or more of nickel, iron, cobalt, manganese, copper, and vanadium.

5. The electrocatalytic method for hydrogen production from hydrogen storage liquid formic acid coupling synthesis according to claim 4, characterized in that: The conductive carrier is nickel foam; the transition metal is nickel or iron.

6. The electrocatalytic method for hydrogen production from hydrogen storage liquid formic acid coupling synthesis according to claim 1, characterized in that, The preparation method of the electrocatalyst includes the following steps: preparation is carried out using a three-electrode system, which includes a working electrode, a counter electrode, and a reference electrode. The working electrode is made of a conductive support. A transition metal salt is used as the transition metal source, and an aqueous solution of the transition metal source is used as the electrochemical deposition solution. The working electrode is placed in the electrochemical deposition solution, and a voltage of -0.6 to -1.5 V vs. RHE is applied for electrochemical deposition. The electrodeposition time lasts for 30 to 90 s. After the electrochemical deposition is completed, the working electrode is removed, washed, and dried to obtain an integrated electrocatalyst.

7. The electrocatalytic method for hydrogen production from hydrogen storage liquid formic acid coupling according to claim 6, characterized in that: The transition metal source in the electrochemical deposition solution includes at least one of nickel nitrate, iron nitrate, cobalt nitrate, copper nitrate, and vanadium nitrate; the concentration of the transition metal source is 10~90 mM.

8. The electrocatalytic method for hydrogen production from hydrogen storage liquid formic acid coupling according to claim 1, characterized in that: The anolyte is a mixed solution of a 0.5-2 M potassium hydroxide solution and a 0.05-1 M glycerol solution; the catholyte is a 0.5-2 M potassium hydroxide solution.

9. The electrocatalytic preparation method for hydrogen synthesis by coupling hydrogen-storing liquid formic acid with hydrogen as described in claim 1, characterized in that: The anolyte is stirred at a rate of 600-1000 rpm during the reaction.

10. The electrocatalytic method for hydrogen production from hydrogen storage liquid formic acid coupling synthesis according to claim 1, characterized in that: The anolyte and the catholyte are separated by a proton exchange membrane made of perfluorosulfonic acid resin.

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