PdFe bimetallic formic acid dehydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of formic acid dehydrogenation catalysis, in particular to a PdFe bimetallic formic acid dehydrogenation catalyst and a preparation method and application thereof.The preparation method comprises the steps that divalent zinc salt is dissolved in methyl alcohol, 2-methylimidazole is added, stirring, centrifuging, washing and drying are conducted, and a zeolite imidazate framework ZIF-8 is prepared; mixing and grinding with sodium ethylene diamine tetracetate ferric salt to obtain a precursor; carrying out annealing treatment to obtain a Fe carbon nitrogen derivative; sequentially carrying out acid washing, filtering, alkali washing, filtering, washing and drying to obtain a catalyst carrier; and adding into a divalent palladium solution for dipping, reducing, centrifuging and drying to obtain the supported PdFe bimetallic formic acid dehydrogenation catalyst. The low-cost iron source is introduced into the Pd-based catalyst, so that the catalytic performance of formic acid dehydrogenation is improved; the prepared catalyst has optimized Fe component and proper graphitization degree, has lower preparation cost and more favorable catalytic active sites, and improves the performance of formic acid decomposition and dehydrogenation.

Description

Technical Field

[0001] The invention relates to the technical field of formic acid dehydrogenation catalysis, and in particular to a PdFe bimetallic formic acid dehydrogenation catalyst and a preparation method and application thereof. Background Art

[0002] The development of hydrogen energy and hydrogen fuel cells is regarded as an effective way to solve the energy crisis. Formic acid, as a liquid organic hydrogen carrier, has the advantages of high hydrogen storage density (4.4wt%, 53g / L), non-toxicity, and mild dehydrogenation conditions. The hydrogen obtained from the decomposition of formic acid can be directly used in proton exchange membrane fuel cells, which can well overcome the difficulties of in-situ hydrogen production, storage, and transportation. However, the side reaction path (dehydration reaction) of formic acid decomposition produces carbon monoxide, which can cause catalyst poisoning and deactivation. Therefore, in order to obtain hydrogen more efficiently, designing and synthesizing formic acid dehydrogenation catalysts with high activity and selectivity is the key to the further development of hydrogen energy and hydrogen fuel cells.

[0003] Pd-based heterogeneous catalysts are often used as the catalyst of choice for the dehydrogenation of formic acid due to their excellent catalytic activity and selectivity. Adding metals such as silver and gold to Pd-based catalysts can effectively regulate the d-band center position of Pd (-1.83 eV) and thus improve the performance of the catalyst. However, these precious metals are often noble metals with high costs, which is not conducive to the industrialization and commercialization of catalysts. Therefore, the introduction of non-precious metals such as manganese, iron, cobalt, nickel, and copper to effectively promote hydrogen production from formic acid has always been a key research topic in the development of Pd-based heterogeneous catalysts.

[0004] Fe has attracted extensive attention as an element with a wide range of sources and low cost. However, at present, PdFe bimetallic catalysts are rarely used in the field of formic acid decomposition and dehydrogenation. Among them, the active components that are mainly concerned with in the few reports are PdFe bimetallic alloys. There are few studies on other components of Fe as active components that interact with Pd nanoparticles to improve the performance of formic acid hydrogen production. Therefore, further research and development of PdFe bimetallic catalysts is of great significance to the large-scale development and use of green and sustainable energy for formic acid hydrogen production. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art, propose a PdFe bimetallic formic acid dehydrogenation catalyst and a preparation method and application thereof, introduce a low-cost iron source sodium iron ethylenediaminetetraacetate into a Pd-based catalyst, and effectively improve the catalytic performance of formic acid dehydrogenation.

[0006] To achieve the above object, the present invention adopts the following specific technical solutions:

[0007] The preparation method of the PdFe bimetallic formic acid dehydrogenation catalyst provided by the present invention comprises the following steps:

[0008] S1, dissolving a divalent zinc salt in methanol, adding 2-methylimidazole, stirring, centrifuging, washing, and drying to obtain a zeolite imidazole ester framework ZIF-8;

[0009] S2, mixing and grinding ZIF-8 and sodium iron ethylenediaminetetraacetate to obtain a precursor;

[0010] S3, annealing the precursor to obtain Fe carbon-nitrogen derivatives;

[0011] S4, sequentially acid-washing, filtering, alkali-washing, filtering, washing, and drying the Fe carbon-nitrogen derivative to obtain a catalyst carrier;

[0012] S5. Add the catalyst carrier into a divalent palladium solution for immersion, reduction, centrifugation and drying to obtain a supported PdFe bimetallic formate dehydrogenation catalyst.

[0013] Furthermore, in step S1, the divalent zinc salt is selected from zinc nitrate or zinc acetate; the stirring time is 10 to 14 hours, and the temperature is 20 to 25° C.; the mass ratio of divalent zinc salt: 2-methylimidazole is 4.40 to 4.45 g: 9.60 to 9.70 g, and the volume of methanol is 290 to 310 mL.

[0014] Furthermore, in step S2, the mass ratio of ZIF-8: ethylenediaminetetraacetic acid sodium iron salt is 1.0-1.1 g: 0.20-0.22 g.

[0015] Furthermore, in step S3, the annealing temperature is 800-1000°C, and the annealing time is 5-7h; the heating rate to the annealing temperature is 3-5°C / min, and the cooling rate of the annealing is 1-3°C / min; the annealing atmosphere is nitrogen or argon.

[0016] Furthermore, in step S4, the acid solution used for pickling is a 1-2 mol / L hydrochloric acid solution, and the pickling time is 22-24 h; the alkaline solution used for alkali washing is a 1-2 mol / L sodium hydroxide solution, and the alkali washing time is 22-24 h; the washing solution is deionized water or distilled water, and the filtrate is washed until the pH value is 7.

[0017] Furthermore, in step S5, the amount of the catalyst carrier is 95-105 mg; the divalent palladium solution is a potassium chloropalladate solution or a chloropalladic acid solution with a concentration of 0.1 mol / L and an amount of 0.5-0.7 mL; the immersion time is 1-3 h; the reducing agent used for reduction is sodium borohydride, and the reduction time is 3-5 h; the drying temperature is 50-60° C., and the drying pressure is -0.1-0.1 MPa.

[0018] The PdFe bimetallic formate dehydrogenation catalyst provided by the present invention is prepared by the above preparation method.

[0019] The invention discloses an application of a PdFe bimetallic formic acid dehydrogenation catalyst in formic acid decomposition to produce hydrogen.

[0020] The present invention can achieve the following technical effects:

[0021] The present invention introduces a low-cost iron source (sodium iron ethylenediaminetetraacetate) into a Pd-based catalyst, thereby effectively improving the catalytic performance of formic acid dehydrogenation; the prepared PdFe bimetallic formic acid dehydrogenation catalyst has an optimized Fe component (C 0.12 Fe 1.88 , FeC, Fe) and appropriate degree of graphitization (I D / I G =0.98), which has lower preparation cost and more favorable catalytic active sites than Pd-based heterogeneous catalysts prepared by other methods, and improves the performance of formic acid decomposition and dehydrogenation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a flow chart of a method for preparing a PdFe bimetallic formic acid dehydrogenation catalyst according to an embodiment of the present invention;

[0023] Figure 2 1 is an X-ray diffraction diagram of the PdFe bimetallic catalyst prepared according to Example 1 of the present invention and the Pd catalyst prepared according to Comparative Example 1;

[0024] Figure 3 is an X-ray diffraction diagram of the catalyst carrier prepared according to Example 2 and Comparative Examples 2 and 3 of the present invention;

[0025] Figure 4 is a Raman spectrum of the catalyst carrier prepared according to Example 2 of the present invention and Comparative Examples 2 and 3;

[0026] Figure 5 is a graph showing the cumulative gas production of formic acid dehydrogenation catalyzed by the PdFe bimetallic catalyst prepared according to Example 1 of the present invention and the Pd catalyst prepared according to Comparative Example 1 over time;

[0027] Figure 6 is a graph showing the cumulative gas production over time of formic acid dehydrogenation catalyzed by the PdFe bimetallic catalyst prepared according to Example 1 of the present invention and Comparative Examples 4 and 5;

[0028] Figure 7 is a conversion frequency diagram of formic acid dehydrogenation catalyzed by the PdFe bimetallic catalyst prepared according to Example 1 of the present invention and Comparative Examples 4 and 5;

[0029] Figure 8 is a cycle performance curve diagram showing the cumulative gas production of formic acid dehydrogenation catalyzed by the PdFe bimetallic catalyst prepared according to Example 1 of the present invention as a function of time;

[0030] Fig. 9 It is a conversion frequency diagram of 5 times of formic acid dehydrogenation catalyzed by the PdFe bimetallic catalyst prepared according to Example 1 of the present invention. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0033] The present invention provides a method for preparing a PdFe bimetallic formic acid dehydrogenation catalyst, the process is as follows: Figure 1 As shown, the following steps are included:

[0034] S1. Dissolve divalent zinc salt in methanol, add 2-methylimidazole, stir, centrifuge, wash and dry to obtain zeolite imidazole framework ZIF-8.

[0035] The divalent zinc salt can be zinc nitrate or zinc acetate. The stirring time is 10 to 14 hours, the temperature is 20 to 25°C, the mass ratio of divalent zinc salt: 2-methylimidazole is 4.40 to 4.45 g: 9.60 to 9.70 g, and the volume of methanol is 290 to 310 mL.

[0036] S2. Mix and grind ZIF-8 and sodium iron ethylenediaminetetraacetate to obtain a precursor.

[0037] The mass ratio of ZIF-8: ethylenediaminetetraacetic acid sodium iron salt is 1.0-1.1 g: 0.20-0.22 g.

[0038] S3. Annealing the precursor to obtain Fe carbon-nitrogen derivatives.

[0039] The annealing temperature is 800-1000°C, and the annealing time is 5-7h; the heating rate to the annealing temperature is 3-5°C / min, the annealing cooling rate is 1-3°C / min, and the annealing atmosphere is nitrogen or argon.

[0040] S4. The Fe carbon-nitrogen derivative is sequentially acid-washed, filtered, alkaline-washed, filtered, washed, and dried to obtain a catalyst carrier.

[0041] The acid solution used for pickling is 1-2 mol / L hydrochloric acid solution, and the pickling time is 22-24 h. The alkaline solution used for alkali washing is 1-2 mol / L sodium hydroxide solution, and the alkaline washing time is 22-24 h. The washing solution is deionized water or distilled water, and the washing is performed until the pH of the filtrate is close to 7.

[0042] S5. Add the catalyst carrier into a divalent palladium solution for immersion, reduction, centrifugation and drying to obtain a supported PdFe bimetallic formate dehydrogenation catalyst.

[0043] The dosage of the catalyst carrier is 95-105 mg; the divalent palladium solution is a potassium chloropalladate solution or a chloropalladic acid solution, both of which are 0.1 mol / L, and the addition amount is 0.5-0.7 mL; the immersion time is 1-3 h, the reducing agent is sodium borohydride, and the reduction time is 3-5 h; the drying temperature is 50-60° C., and the drying pressure is -0.1-0.1 MPa (under vacuum conditions).

[0044] The PdFe bimetallic formic acid dehydrogenation catalyst provided in the embodiment of the present invention is prepared by the above preparation method, and has an Fe optimized component and a suitable graphitization degree. The Pd-supported formic acid dehydrogenation catalyst can be applied to the field of formic acid decomposition and hydrogen production.

[0045] The preparation method of the PdFe bimetallic formate dehydrogenation catalyst provided by the present invention is described below with reference to specific examples.

[0046] Example 1

[0047] Dissolve 4.41g Zn(NO3)2·6H2O in 300mL methanol at room temperature. Add 9.66g 2-methylimidazole to the above solution with stirring. Stir the mixture at room temperature overnight for 12h, centrifuge to obtain a white precipitate, and wash with methanol. Finally, vacuum dry at 60℃ to obtain ZIF-8. Mix 1.0g ZIF-8 and 0.2g sodium ethylenediaminetetraacetic acid iron salt and grind them, put them in a tube furnace, heat to 900℃ at 4℃ / min, heat in a nitrogen flow in a tube furnace at 900℃ for 120 minutes, and then cool to room temperature to obtain Fe carbon nitrogen derivatives. In order to remove impurities remaining on the surface, soak them in 2mol / L hydrochloric acid solution and 2mol / L sodium hydroxide solution for 24h respectively, then wash them with a large amount of deionized water, and dry them at 60℃ to obtain the catalyst carrier. Disperse 100 mg of the catalyst support in 5 mL of deionized water, stir at room temperature, then add 0.6 mL of 0.1 mol / L potassium chloropalladate solution, and continue stirring for 1 hour. Add 15 mg of fresh sodium borohydride solid dissolved in 1 mL of deionized water to the above solution and stir for 3 hours. Finally, centrifuge the obtained PdFe bimetallic catalyst, wash it with deionized water 3 times, and vacuum dry it at 60°C to obtain a PdFe bimetallic formate dehydrogenation catalyst.

[0048] Example 2

[0049] Dissolve 4.41g Zn(NO3)2·6H2O in 300mL methanol at room temperature. Add 9.66g 2-methylimidazole to the above solution with stirring. Stir the mixture at room temperature overnight for 12h, centrifuge to obtain a white precipitate, and wash with methanol. Finally, vacuum dry at 60℃ to obtain ZIF-8. Mix 1.0g ZIF-8 and 0.2g sodium ethylenediaminetetraacetic acid iron salt and grind them, put them in a tube furnace, heat to 900℃ at 4℃ / min, heat in a nitrogen flow in a tube furnace at 900℃ for 120 minutes, and then cool to room temperature to obtain Fe carbon nitrogen derivatives. In order to remove impurities remaining on the surface, soak them in 2mol / L hydrochloric acid solution and 2mol / L sodium hydroxide solution for 24h respectively, then wash them with a large amount of deionized water, and dry them at 60℃ to obtain the catalyst carrier.

[0050] Comparative Example 1

[0051] Dissolve 4.41g Zn(NO3)2·6H2O in 300mL methanol at room temperature. Add 9.66g 2-methylimidazole to the above solution with stirring. Stir the mixture at room temperature overnight for 12h, centrifuge to obtain a white precipitate, and wash with methanol. Finally, vacuum dry at 60℃ to obtain ZIF-8. Mix 1.0g ZIF-8 and 0.2g disodium ethylenediaminetetraacetic acid, grind them, put them in a tube furnace, heat to 900℃ at 4℃ / min, heat them in a nitrogen flow in a tube furnace at 900℃ for 120 minutes, and then cool them to room temperature to obtain a carbon nitrogen derivative. Disperse 100mg of the carbon nitrogen derivative in 5mL of deionized water, stir at room temperature, then add 0.6mL of 0.1mol / L potassium chloropalladate solution, and continue stirring for 1h. Add 15mg of fresh sodium borohydride solid dissolved in 1mL of deionized water to the above solution and stir for 3h. Finally, the obtained PdFe bimetallic catalyst was centrifuged, washed three times with deionized water, and dried at 60 °C in vacuum.

[0052] Comparative Example 2

[0053] Dissolve 4.41g Zn(NO3)2·6H2O in 300mL methanol at room temperature. Add 9.66g 2-methylimidazole to the above solution with stirring. Stir the mixture at room temperature overnight for 12h, centrifuge to obtain a white precipitate, and wash with methanol. Finally, vacuum dry at 60℃ to obtain ZIF-8. Mix 1.0g ZIF-8 and 0.2g sodium ethylenediaminetetraacetic acid iron salt and grind them, put them in a tube furnace, heat to 800℃ at 4℃ / min, heat in a nitrogen flow in a tube furnace at 800℃ for 120 minutes, and then cool to room temperature to obtain Fe carbon nitrogen derivatives. In order to remove impurities remaining on the surface, soak them in 2mol / L hydrochloric acid solution and 2mol / L sodium hydroxide solution for 24h respectively, then wash them with a large amount of deionized water, and dry them at 60℃ to obtain the catalyst carrier.

[0054] Comparative Example 3

[0055] Dissolve 4.41g Zn(NO3)2·6H2O in 300mL methanol at room temperature. Add 9.66g 2-methylimidazole to the above solution with stirring. Stir the mixture at room temperature overnight for 12h, centrifuge to obtain a white precipitate, and wash with methanol. Finally, vacuum dry at 60℃ to obtain ZIF-8. Mix 1.0g ZIF-8 and 0.2g sodium ethylenediaminetetraacetic acid iron salt and grind them, put them in a tube furnace, heat to 1000℃ at 4℃ / min, heat in a nitrogen flow in a tube furnace at 1000℃ for 120 minutes, and then cool to room temperature to obtain Fe carbon nitrogen derivatives. In order to remove impurities remaining on the surface, soak them in 2mol / L hydrochloric acid solution and 2mol / L sodium hydroxide solution for 24h respectively, then wash them with a large amount of deionized water, and dry them at 60℃ to obtain the catalyst carrier.

[0056] Comparative Example 4

[0057] 100 mg of the catalyst support obtained in Comparative Example 2 was dispersed in 5 mL of deionized water, stirred at room temperature, and then 0.6 mL of 0.1 mol / L potassium chloropalladate solution was added, and stirring was continued for 1 h. 15 mg of fresh sodium borohydride solid dissolved in 1 mL of deionized water was added to the above solution and stirred for 3 h. Finally, the resulting mixture was centrifuged, washed with deionized water 3 times, and vacuum dried at 60 ° C to obtain a PdFe bimetallic catalyst.

[0058] Comparative Example 5

[0059] 100 mg of the catalyst support obtained in Comparative Example 2 was dispersed in 5 mL of deionized water, stirred at room temperature, and then 0.6 mL of 0.1 mol / L potassium chloropalladate solution was added, and stirring was continued for 1 h. 15 mg of fresh sodium borohydride solid dissolved in 1 mL of deionized water was added to the above solution and stirred for 3 h. Finally, the resulting mixture was centrifuged, washed with deionized water 3 times, and vacuum dried at 60° C. to obtain a PdFe bimetallic catalyst.

[0060] Figure 2 is the X-ray diffraction pattern of the catalyst prepared in Example 1 and Comparative Example 1, Figure 2 It can be seen that the diffraction peaks of the samples in Example 1 and Comparative Example 1 correspond to the standard cards one by one, indicating that the metal components of the samples are mainly Pd, C 0.12 Fe 1.88 , FeC and Fe, while the comparative example only has Pd metal component.

[0061] Figure 3 is the X-ray diffraction pattern of the catalyst carrier prepared in Example 2 and Comparative Examples 2 and 3. Figure 3 It can be seen that the diffraction peaks of the catalyst support sample correspond to the standard card one by one, indicating that the Fe composition of the catalyst support sample is C 0.12 Fe 1.88 , FeC and Fe, Fe3C, Fe and C 0.12 Fe 1.88 , FeC and Fe.

[0062] Figure 4 is the Raman spectra of the catalyst supports prepared in Example 2 and Comparative Examples 2 and 3. Figure 4 It can be seen that the graphitization degree (I D / I G ) are 0.98, 1.11, and 0.86, respectively, indicating that efficient catalysts require the catalyst carrier to have an appropriate degree of graphitization.

[0063] Figure 5 The graph is a graph showing the cumulative gas production over time of formic acid dehydrogenation catalyzed by the PdFe bimetallic catalyst prepared in Example 1 and the Pd catalyst prepared in Comparative Example 1. Calculations show that the PdFe bimetallic catalyst has achieved complete conversion of formic acid in less than 4 minutes, while the Pd catalyst has not achieved complete conversion of formic acid in 10 minutes, indicating that the PdFe bimetallic catalyst has a higher formic acid dehydrogenation performance.

[0064] Figure 6 is a curve showing the cumulative gas production of formic acid dehydrogenation catalyzed by the PdFe bimetallic catalyst prepared in Example 1 and Comparative Examples 4 and 5 over time. Figure 6It can be seen that the formic acid complete conversion time of the sample in Example 1 and the sample in Comparative Example 5 is similar, while the sample in Comparative Example 4 still does not reach complete conversion within 10 minutes, indicating that the performance of the comparative example is poor. Figure 3 It can be seen that C 0.12 Fe 1.88 , FeC component has higher activity than Fe3C.

[0065] Figure 7 The conversion frequency diagram of formic acid dehydrogenation catalyzed by the PdFe bimetallic catalyst prepared in Example 1 and Comparative Examples 4 and 5 is shown in FIG. 1 . The conversion frequencies of samples in Example 1 and Comparative Examples 4 and 5 are 7142.9 h -1 , 1546.4h -1 and 6818.2h -1 , indicating that the order of their catalytic rates of formic acid is implementation 1> comparative example 5> comparative example 4. Figure 3 , 4 It can be seen that under conditions of similar components, the degree of graphitization is also an important factor affecting the performance of the catalyst.

[0066] Figure 8 is the performance curve of 5 cycles of formic acid dehydrogenation catalyzed by the PdFe bimetallic catalyst prepared in Example 1, Figure 8 It can be seen that in the 5 catalyst cycle experiments, the sample of Example 1 can achieve complete conversion within 5 minutes, which proves that the PdFe bimetallic catalyst has good cycle stability.

[0067] Fig. 9 This is a conversion frequency diagram of five cycles of formic acid dehydrogenation catalyzed by the PdFe bimetallic catalyst prepared in Example 1. It can be calculated that the catalytic rate of the fifth cycle of the sample in Example 1 can still reach 95% of the first cycle, indicating that the catalyst activity can still maintain a high catalytic activity after multiple cycles.

[0068] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0069] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

[0070] The above specific implementations of the present invention do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a PdFe bimetallic formic acid dehydrogenation catalyst, It is characterized in that The steps include: S1, dissolving a divalent zinc salt in methanol, adding 2-methylimidazole, stirring, centrifuging, washing, and drying to obtain a zeolite imidazole ester framework ZIF-8; S2, mixing and grinding ZIF-8 and sodium iron ethylenediaminetetraacetate to obtain a precursor; S3, annealing the precursor to obtain Fe carbon-nitrogen derivatives; S4, sequentially acid-washing, filtering, alkali-washing, filtering, washing, and drying the Fe carbon-nitrogen derivative to obtain a catalyst carrier; S5. Add the catalyst carrier into a divalent palladium solution for immersion, reduction, centrifugation and drying to obtain a supported PdFe bimetallic formate dehydrogenation catalyst.

2. The preparation method of the PdFe bimetallic formate dehydrogenation catalyst according to claim 1, It is characterized in that In step S1, the divalent zinc salt is selected from zinc nitrate or zinc acetate; the stirring time is 10 to 14 hours, and the temperature is 20 to 25° C.; the mass ratio of the divalent zinc salt: 2-methylimidazole is 4.40 to 4.45 g: 9.60 to 9.70 g, and the volume of methanol is 290 to 310 mL.

3. The preparation method of the PdFe bimetallic formate dehydrogenation catalyst according to claim 1, It is characterized in that In step S2, the mass ratio of ZIF-8: ethylenediaminetetraacetic acid sodium iron salt is 1.0-1.1 g: 0.20-0.22 g.

4. The preparation method of the PdFe bimetallic formate dehydrogenation catalyst according to claim 1, It is characterized in that In step S3, the annealing temperature is 800-1000°C, and the annealing time is 5-7h; the heating rate to the annealing temperature is 3-5°C / min, and the annealing cooling rate is 1-3°C / min; the annealing atmosphere is nitrogen or argon.

5. The preparation method of the PdFe bimetallic formate dehydrogenation catalyst according to claim 1, It is characterized in that In step S4, the acid solution used for pickling is a 1-2 mol / L hydrochloric acid solution, and the pickling time is 22-24 hours; the alkaline solution used for alkali washing is a 1-2 mol / L sodium hydroxide solution, and the alkaline washing time is 22-24 hours; the washing solution is deionized water or distilled water, and the washing is performed until the filtrate pH = 7.

6. The preparation method of the PdFe bimetallic formate dehydrogenation catalyst according to claim 1, It is characterized in that In step S5, the dosage of the catalyst carrier is 95-105 mg; the divalent palladium solution is selected from potassium chloropalladate solution or chloropalladic acid solution, with a concentration of 0.1 mol / L and a dosage of 0.5-0.7 mL; the immersion time is 1-3 h; the reducing agent used for reduction is sodium borohydride, and the reduction time is 3-5 h; the drying temperature is 50-60° C., and the drying pressure is -0.1-0.1 MPa.

7. A PdFe bimetallic formic acid dehydrogenation catalyst, It is characterized in that The invention is prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the PdFe bimetallic formate dehydrogenation catalyst as claimed in claim 7 in hydrogen production by decomposing formic acid.

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