Formic acid decomposition hydrogen production catalyst with light response characteristics and preparation method thereof

Abstract

The present application relates to the field of new energy hydrogen storage and catalytic hydrogen production technology, in particular to a formic acid decomposition hydrogen production catalyst with light response characteristics and a preparation method thereof. In order to achieve the purpose of wide spectrum response and high efficient hydrogen production, the catalyst design adopts the method of N-doped modified semiconductor catalyst CeO2, improves the spectrum response range of the catalyst CeO2 under visible light, and the loaded metal Pd acts as an active catalytic metal for high efficient catalytic formic acid decomposition hydrogen production, and further modifies the semiconductor catalyst CeO2, further improves the light response performance and photocatalytic efficiency of CeO2, and the selectivity of catalytic formic acid hydrogen production is 100%.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy hydrogen storage and catalytic hydrogen production, and in particular to a formic acid decomposition hydrogen production catalyst with light response characteristics and a preparation method thereof. Background Art

[0002] Hydrogen energy boasts the advantages of being pollution-free, renewable, and widely available. It also boasts a high specific energy density, and its final product, water, makes it considered one of the most ideal energy sources. To promote the development of the hydrogen energy industry, my country has introduced a series of supportive policies. Therefore, promoting its application requires addressing technical challenges related to hydrogen production and storage during its utilization. Hydrogen storage technologies using solid / liquid chemical materials (such as formic acid and methane) hold the greatest promise for resolving these storage and transportation challenges. However, current challenges include the slow hydrogen production reaction kinetics of these storage materials.

[0003] Formic acid (HCOOH) has the advantages of wide sources, stable chemical properties, liquid at room temperature and pressure, and high hydrogen mass fraction (4.8wt%). In addition, formic acid is not easy to burn, safe and convenient to transport and store, and formic acid belongs to Class C. Formic acid has obvious safety advantages in terms of stacking standards and total amount, and is a highly promising chemical hydrogen storage material. Formic acid can undergo dehydrogenation reaction and release H2 under the action of a catalyst at room temperature and pressure. Formic acid hydrogen production technology shows important application potential in distributed energy, industrial production and agricultural innovation. In the process of catalytic formic acid hydrogen production reaction, formic acid is first adsorbed on the catalyst surface, the OH bond is broken, and HCOO is generated. - and H + , HCOO - Activation causes the C-H bond to break, generating CO2 and releasing H + , H + and H generated in the previous step + Combined with the formic acid, H2 is generated, completing the dehydrogenation. However, the formic acid dehydrogenation reaction is often subject to competition from the dehydration reaction pathway, producing byproducts such as H2O and CO. Therefore, the design and preparation of highly active and selective catalysts is one of the key issues that need to be addressed in formic acid hydrogen production technology.

[0004] Cerium dioxide (CeO2) is a highly active semiconductor photocatalytic material, offering advantages such as high stability, low toxicity, low cost, and ease of scalable synthesis. CeO2 has a wide band gap (approximately 3.2 eV), which can be regulated by doping with heterogeneous elements. Due to its excellent redox properties and stability, ceria photocatalytic technology is gaining widespread application in environmental remediation, energy conversion, organic synthesis, and other fields. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a light-responsive catalyst for formic acid decomposition to produce hydrogen, and a method for its preparation. This catalyst can catalyze formic acid decomposition to produce hydrogen in the absence of light. In the presence of light, it rapidly responds to light, generating a photo-coupled synergistic catalytic effect that enhances the formic acid decomposition to produce hydrogen, resulting in high formic acid hydrogen production performance. The catalyst preparation method is simple and suitable for large-scale, batch production.

[0006] The present invention discloses a formic acid decomposition hydrogen production catalyst with light-responsive characteristics. To achieve the goals of wide-spectrum response and efficient hydrogen production, the catalyst design adopts a method of N-doping and modifying the semiconductor catalyst CeO2 to improve the spectral response range of the catalyst CeO2 in visible light. The loaded metal Pd not only serves as an active catalytic metal for efficiently catalyzing the decomposition of formic acid to produce hydrogen, but also plays a role in further modifying the semiconductor catalyst CeO2, further improving the light-responsiveness performance and photocatalytic efficiency of CeO2.

[0007] The present invention provides a method for preparing a formic acid decomposition hydrogen production catalyst with light-responsive characteristics, which specifically comprises the following steps:

[0008] (1) Ce(NO3)3•6H2O was dissolved in deionized water to obtain Ce(NO3)3 solution, and then NaOH aqueous solution was slowly added dropwise to the Ce(NO3)3 solution, and magnetic stirring was performed during the addition process. Then CO(NH2)2 aqueous solution was added, and then magnetic stirring was performed to mix them evenly. The obtained mixed solution was transferred to a high-pressure reactor, and then the high-pressure reactor was placed in a constant temperature box at 180℃~200℃ for reaction, and the reaction time was not less than 24h; after the reaction was completed, it was cooled to room temperature, the reaction solution was centrifuged, the supernatant was discarded, the precipitate was washed, dried, and calcined at a certain temperature to obtain N-doped CeO2, which was recorded as N-CeO2;

[0009] (2) N-CeO2 was ultrasonically dispersed in deionized water to form an N-CeO2 suspension. 3-Aminopropyltriethoxysilane (APTS) was added to the suspension and stirred. PdCl2 was also added to the suspension and stirred thoroughly to obtain a dispersion. The newly prepared NaBH4 aqueous solution was then added dropwise to the dispersion while stirring vigorously. The reaction time was not less than 30 min. After the reaction was completed, the obtained product was centrifuged, washed, dried, and ground to obtain a formic acid decomposition hydrogen production catalyst with light-responsive characteristics, which was recorded as PdN-CeO2.

[0010] Furthermore, in step (1), the precipitate was washed three times with deionized water and anhydrous ethanol respectively;

[0011] Furthermore, in step (1), the calcination is carried out at 350°C to 550°C for 4-6 hours;

[0012] Furthermore, in step (1), the molar concentration of the Ce(NO3)3 solution is 1-5 mol / L, the molar concentration of the NaOH aqueous solution is 1 mol / L; and the concentration of the CO(NH2)2 aqueous solution is 0.5-1.5 mol / L.

[0013] Furthermore, in step (1), the volume ratio of the CO(NH2)2 aqueous solution to the Ce(NO3)3 solution is (1-3):20;

[0014] Furthermore, in step (2), N-CeO2 is ultrasonically dispersed in deionized water to form an N-CeO2 suspension with a concentration of 0.1-0.4 g / mL;

[0015] Furthermore, 0.5-3.5 mL of APTS was added to the N-CeO2 suspension in step (2) and stirred for 30 min.

[0016] Furthermore, the mass ratio of the Pd atomic mass in the PdCl2 added in step (2) to the N-CeO2 is 1% to 12%, and the molar concentration of the NaBH4 aqueous solution is 1.0 to 2.5 mol / L.

[0017] The method for preparing the formic acid decomposition hydrogen production catalyst with light-responsive characteristics provided by the present invention can also adopt the following steps:

[0018] (1) At room temperature, trisodium citrate dihydrate and CO(NH2)2 were dissolved in deionized water in succession and stirred to fully dissolve the solutes to obtain solution A; Ce(NO3)3•6H2O was then added to solution A and stirred continuously to obtain solution B. Solution B was then transferred to a high-pressure reactor and the high-pressure reactor was placed in a thermostat for heat preservation. After the heat preservation was completed, the solution was naturally cooled to room temperature to obtain solution C. PdCl2 was added to solution C and stirred thoroughly to obtain solution D. The newly prepared NaBH4 aqueous solution was then added dropwise to solution D while stirring vigorously. The reaction time was not less than 50 min. After the reaction was completed, the product was washed with anhydrous ethanol and deionized water respectively to remove impurities in the product; the washed solution was centrifuged to obtain a precipitate, and the precipitate was dried;

[0019] (2) The powder obtained after drying in step (1) is calcined under an argon atmosphere to obtain a formic acid decomposition hydrogen production catalyst with photoresponsive characteristics, which is denoted as PdN-CeO2.

[0020] Furthermore, in the method, in step (1), Ce(NO3)3•6H2O is added to solution A and stirred for 2 hours to obtain solution B; the high-pressure reactor is placed in a constant temperature box at 180-200°C and kept warm for 24 hours; the concentration of the newly prepared NaBH4 aqueous solution is 1.0-2.5 mol / L; after the reaction is completed, the solution is washed with anhydrous ethanol and deionized water three times respectively; the precipitate is dried at 80°C for 5 hours;

[0021] Furthermore, in step (2) of the method, the powder is calcined in an argon atmosphere at 350-550° C. for 4-6 hours.

[0022] The present invention also aims to provide a formic acid decomposition hydrogen production catalyst having light-responsive characteristics obtained by the above two preparation methods.

[0023] The principle of the preparation method of the formic acid decomposition hydrogen production catalyst with light-responsive characteristics of the present invention is as follows: a wide-bandgap semiconductor catalyst CeO2 with corrosion resistance and a simple preparation method is used, the semiconductor catalyst CeO2 is doped and modified with the N element, and the function of the N element as an electron acceptor is utilized to dope the outer electron orbits of the Ce atoms in CeO2, thereby reducing the bandgap width of CeO2 and thereby improving the response ability of CeO2 to long-wavelength light; then, Pd metal elements are in-situ generated and deposited on the N-CeO2 of the N-doped CeO2. The Pd metal not only has the function of efficiently catalyzing the decomposition of formic acid to produce hydrogen, but also regulates the energy band structure of CeO2, thereby further improving the response ability of CeO2 to long-wavelength light. At the same time, the metal conductor properties of the Pd metal can effectively separate photogenerated electron-hole pairs, reduce the recombination rate of photogenerated electrons-holes, and thereby improve the photocatalytic efficiency.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention provides a catalyst for catalyzing formic acid decomposition and efficient hydrogen production, which is simple to synthesize, easy to commercialize, and has a broad spectral response. The catalyst exhibits a wide spectral response, utilizing long-wavelength visible light and even infrared light, achieving 100% selectivity for catalyzing formic acid-derived hydrogen production. The catalyst also exhibits high activity at room temperature (25°C). The catalyst's simple synthesis process facilitates batch production and is suitable for widespread commercialization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Spectral response influence diagrams of PdN-CeO2 obtained in Example 1 of the present invention, N-CeO2 obtained in step (1) of Example 1, CeO2 obtained in Comparative Example 1, and Pd-CeO2 obtained in Comparative Example 2;

[0027] Figure 2This is a SEM image of the catalyst PdN-CeO2 obtained in Example 1 of the present invention;

[0028] Figure 3 The catalytic formic acid decomposition and gas production performance of the catalyst PdN-CeO2 obtained in Examples 1 and 2 of the present invention under illumination conditions and non-illumination conditions respectively;

[0029] Figure 4 for Figure 3 Composition analysis spectrum of the gas produced by the decomposition of formic acid catalyzed by PdN-CeO2 in Example 1 under medium light conditions. DETAILED DESCRIPTION

[0030] In order to better understand the content of the present invention, the present invention will be further described below in conjunction with specific examples and drawings. The following examples are implemented based on the technology of the present invention and provide detailed implementation methods and operating steps, but the scope of protection of the present invention is not limited to the following examples.

[0031] In specific implementation, the order of doping the N element and depositing the Pd metal element can be swapped. For example, in Example 1, the N element is doped first and then the Pd metal element is deposited, while in Example 2, the Pd metal element is deposited first and then the N element is doped. The purity of APTS is 99%.

[0032] Example 1:

[0033] (1) 20 g of Ce(NO3)3•6H2O was dissolved in deionized water to obtain a Ce(NO3)3 solution with a molar concentration of 1.0 mol / L. Then, 15 mL of a 1 mol / L NaOH aqueous solution was slowly added dropwise to the Ce(NO3)3 solution. During the addition, magnetic stirring was performed to ensure uniform mixing. Subsequently, 5 mL of a 0.5 mol / L CO(NH2)2 solution was added. The mixture was then magnetically stirred for 20 min to ensure uniform mixing. The obtained mixed solution was transferred to a high-pressure reactor, and the high-pressure reactor was placed in a constant temperature box at 180°C for reaction for 24 h. After the reaction was completed, the reaction solution was cooled to room temperature, and the obtained solution was centrifuged and the supernatant was discarded. The precipitate was washed with deionized water and anhydrous ethanol three times respectively, and then dried at 80°C for 5 h. The powdery substance obtained after drying was transferred to a calcination furnace and calcined at 500°C for 5 h to obtain an N-doped CeO2 sample, which was recorded as N-CeO2.

[0034] (2) Weigh 8 g of the N-CeO2 sample obtained in step (1) and ultrasonically disperse it in 40 mL of deionized water to form an N-CeO2 suspension. Add 0.6 mL of APTS to the suspension and stir for 30 min. Then add 0.14 g of PdCl2 to the suspension and stir thoroughly to obtain a dispersion. Then, add 10 mL of a newly prepared 2 mol / L NaBH4 solution dropwise to the dispersion while stirring vigorously. The reaction time is 50 min. After the reaction is completed, the obtained product is centrifuged, the supernatant is discarded, and the precipitate is washed with deionized water. Finally, it is dried and ground to obtain a formic acid decomposition hydrogen production catalyst with light-responsive characteristics, which is recorded as PdN-CeO2.

[0035] Example 2:

[0036] (1) At room temperature, 1.5 g of trisodium citrate dihydrate and 1.0 g of CO(NH2)2 were dissolved in 40 mL of deionized water, and magnetically stirred to fully dissolve the solutes to obtain solution A. Then, 20 g of Ce(NO3)3·6H2O was added to solution A and stirred at room temperature for 2 h to fully dissolve the cerium nitrate and mix with the other components in solution A to obtain solution B. Solution B was then transferred to a high-pressure reactor, and the high-pressure reactor was placed in a constant temperature box at 180°C for 24 h. During the insulation process, the substances in the solution will undergo chemical reactions. After the insulation is completed, the solution was naturally cooled to room temperature to obtain solution C. 0.39 g of PdCl2 was added to solution C and stirred thoroughly to obtain solution D. Then, 10 mL of a newly prepared 2 mol / L NaBH4 aqueous solution was added dropwise to solution D with vigorous stirring. The reaction time was 50 min. After the reaction is completed, the obtained solution is centrifuged to obtain a precipitate, which is then washed three times with anhydrous ethanol and three times with deionized water to remove impurities, and then dried at 80°C for 5 hours to remove moisture.

[0037] (2) The powder obtained after drying in step (1) was calcined at 500° C. for 5 hours in an argon atmosphere to obtain a formic acid decomposition hydrogen production catalyst with photoresponsive characteristics, which was recorded as PdN-CeO2.

[0038] Example 3:

[0039] (1) 30 g of Ce(NO3)3•6H2O was dissolved in deionized water to obtain a Ce(NO3)3 solution with a molar concentration of 2.0 mol / L. Then, 15 mL of a 1 mol / L NaOH aqueous solution was slowly added dropwise to the Ce(NO3)3 solution. During the addition, magnetic stirring was performed to ensure uniform mixing. Subsequently, 5 mL of a 0.5 mol / L CO(NH2)2 solution was added. The mixture was then magnetically stirred for 20 min to ensure uniform mixing. The obtained mixed solution was transferred to a high-pressure reactor, and the high-pressure reactor was placed in a constant temperature box at 200 °C for reaction for 24 h. After the reaction was completed, the reaction solution was cooled to room temperature, and the obtained solution was centrifuged and the supernatant was discarded. The precipitate was washed with deionized water and anhydrous ethanol three times respectively, and then dried at 80 °C for 5 h. The powdery substance obtained after drying was transferred to a calcination furnace and calcined at 450 °C for 5 h to obtain an N-doped CeO2 sample, which was recorded as N-CeO2.

[0040] (2) Weigh 16 g of the N-CeO2 sample obtained in step (1) and ultrasonically disperse it in 50 mL of deionized water to form an N-CeO2 suspension. Add 0.6 mL of APTS to the suspension and stir for 30 min. Then add 0.28 g of PdCl2 to the suspension and stir thoroughly to obtain a dispersion. Then, add 10 mL of a newly prepared 2.5 mol / L NaBH4 solution dropwise to the dispersion while stirring vigorously. The reaction time is 50 min. After the reaction is completed, the obtained product is centrifuged, the supernatant is discarded, and the precipitate is washed with deionized water. Finally, it is dried and ground to obtain a formic acid decomposition hydrogen production catalyst with light-responsive characteristics, which is recorded as PdN-CeO2.

[0041] Example 4:

[0042] (1) At room temperature, 3 g of trisodium citrate dihydrate and 1.5 g of CO(NH2)2 were dissolved in 40 mL of deionized water, and magnetically stirred to fully dissolve the solutes to obtain solution A. Then, 40 g of Ce(NO3)3·6H2O was added to solution A and stirred at room temperature for 2 h to fully dissolve the cerium nitrate and mix with the other components in solution A to obtain solution B. Solution B was then transferred to a high-pressure reactor, and the high-pressure reactor was placed in a constant temperature box at 200°C for 24 h. During the insulation process, the substances in the solution will undergo chemical reactions. After the insulation is completed, the solution was naturally cooled to room temperature to obtain solution C. 0.78 g of PdCl2 was added to solution C and stirred thoroughly to obtain solution D. Then, 10 mL of a newly prepared 2.5 mol / L NaBH4 aqueous solution was added dropwise to solution D with vigorous stirring. The reaction time was 50 min. After the reaction, the obtained solution was centrifuged to obtain a precipitate, which was washed three times with anhydrous ethanol and three times with deionized water to remove impurities. The precipitate was then dried at 80° C. for five hours to remove moisture.

[0043] (2) The powder obtained after drying in step (1) was calcined at 450° C. for 5 hours in an argon atmosphere to obtain a formic acid decomposition hydrogen production catalyst with photoresponsive characteristics, which was recorded as PdN-CeO2.

[0044] Comparative Example 1:

[0045] 20 g of Ce(NO3)3•6H2O was dissolved in deionized water to obtain a Ce(NO3)3 solution with a molar concentration of 2.0 mol / L, and then 15 mL of a 1 mol / L NaOH aqueous solution was slowly added dropwise to the Ce(NO3)3 solution. During the addition, magnetic stirring was performed to ensure uniform mixing. The obtained mixed solution was transferred to a high-pressure reactor, and the high-pressure reactor was placed in a constant temperature box at 180°C for reaction for 24 hours. After the reaction was completed, it was cooled to room temperature, and the obtained solution was centrifuged and the supernatant was discarded. The precipitate was washed with deionized water and anhydrous ethanol three times respectively, and then dried at 80°C for 5 hours. The powdery substance obtained after drying was transferred to a calcination furnace and calcined at 500°C for 5 hours to obtain a pure CeO2 sample, recorded as CeO2.

[0046] Comparative Example 2:

[0047] 8 g of the CeO2 sample obtained in Comparative Example 1 was weighed and ultrasonically dispersed in 40 mL of deionized water to form a CeO2 suspension. 0.6 mL of APTS was added to the suspension, followed by stirring for 30 minutes. 0.14 g of PdCl2 was then added to the suspension and stirred thoroughly to obtain a dispersion. 10 mL of a freshly prepared 2 mol / L NaBH4 solution was then added dropwise to the dispersion with vigorous stirring for 50 minutes. After the reaction, the resulting product was centrifuged, the supernatant discarded, and the precipitate washed with deionized water, dried, and ground to obtain a semiconductor catalyst under Pd metal deposition, designated Pd-CeO2.

[0048] Figure 1 The spectral response influence curves of PdN-CeO2 obtained in Example 1 of the present invention, N-CeO2 obtained in step (1) of Example 1, CeO2 obtained in Comparative Example 1, and Pd-CeO2 obtained in Comparative Example 2 are shown in the figure. The figure shows that the doping of non-metallic element N (N-CeO2) improves the response absorption capacity of CeO2 in the long wavelength range of 300nm to 800nm, while the doping of metallic element Pd (Pd-CeO2) improves the response absorption capacity of CeO2 in the short wavelength range of 100nm to 250nm. The catalyst PdN-CeO2 modified by co-doping with N and Pd has significantly improved light response absorption capacity over the entire wavelength range.

[0049] Figure 2 This is the SEM image of the catalyst PdN-CeO2 obtained in Example 1. Figure 2 As can be seen from the figure, the catalyst prepared by the hydrothermal method in Example 1 has a honeycomb pore structure with a pore size of 20-50 nm. The honeycomb pore structure is beneficial for increasing the specific surface area of ​​the catalyst, improving the adsorption capacity of reactants on the catalyst surface, and thus facilitating the catalytic reaction.

[0050] The catalyst PdN-CeO2 prepared in Examples 1 and 2 was subjected to formic acid decomposition to produce hydrogen. The reactant formic acid was analytically pure formic acid. The added mass ratio of the catalyst and formic acid was 1:10. The reaction temperature was controlled at 50°C by a thermocouple and a water jacket. The amount of gas produced was collected and measured by the drainage method. Before the experiment, nitrogen with a purity of 99.99% was used to purge the experimental device and pipeline to ensure that all air in the device and pipeline was exhausted. The purity of the product hydrogen was measured by gas chromatograph using a 50W xenon lamp to simulate sunlight.

[0051] Figure 3 The catalytic performance of formic acid decomposition and gas production of the catalyst PdN-CeO2 obtained in Example 1 and Example 2 under illumination and non-illumination conditions respectively. Figure 3It can be seen that under non-illumination conditions, the catalysts PdN-CeO2 corresponding to Example 1 and Example 2 can both efficiently catalyze the decomposition of formic acid to generate a mixed gas. The rate at which the catalyst PdN-CeO2 corresponding to Example 1 catalyzes the decomposition of formic acid to generate a mixed gas is slightly higher than that of the catalyst PdN-CeO2 corresponding to Example 2. At the same time, the catalysts in both examples can respond to visible light; under illumination conditions, the efficiency and rate of formic acid decomposition to generate a mixed gas are improved. For the catalyst obtained in Example 1, with the introduction of illumination conditions, the rate at which formic acid decomposes to generate a mixed gas is increased from 0.29 mL / min to 0.38 mL / min.

[0052] Figure 4 for Figure 3 Compositional analysis of the gas produced by the formic acid decomposition catalyzed by the PdN-CeO2 catalyst in Example 1 under medium illumination conditions. Gas chromatography analysis of the gas produced by the formic acid decomposition catalyzed by the catalyst revealed that the gas primarily contained H2 and CO2, with no CO. This indicates that the primary reaction in the formic acid decomposition catalyzed by the PdN-CeO2 catalyst in this example is formic acid dehydrogenation, with a hydrogen production selectivity of 100%. The N2 signal peak in the figure indicates residual high-purity nitrogen from the purge of the experimental apparatus and pipelines.

[0053] The above description is merely an embodiment of the present invention and does not constitute any form of limitation to the present invention. The present invention may also have other forms of embodiments based on the above structures and functions, which are not listed here one by one. Therefore, any simple modification, equivalent changes, and modifications made to the above embodiments by any person skilled in the art in accordance with the technical essence of the present invention without departing from the scope of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. Application of a catalyst in photocatalytic decomposition of formic acid to produce hydrogen, characterized in that: The preparation method of the catalyst specifically comprises the following steps: (1) Ce(NO3)3•6H2O was dissolved in deionized water to obtain Ce(NO3)3 solution, and then NaOH aqueous solution was slowly added dropwise to the Ce(NO3)3 solution, and magnetic stirring was performed during the addition process. Then CO(NH2)2 aqueous solution was added and magnetic stirring was performed to mix uniformly. The obtained mixed solution was transferred to a high-pressure reactor, and then the high-pressure reactor was placed in a constant temperature box at 180℃~200℃ for reaction, and the reaction time was not less than 24h. After the reaction was completed, it was cooled to room temperature, the reaction solution was centrifuged, the supernatant was discarded, the precipitate was washed and dried, and calcined at 350℃~550℃ for 4-6h to obtain N-doped CeO2, which was recorded as N-CeO2. (2) N-CeO2 was ultrasonically dispersed in deionized water to form an N-CeO2 suspension with a concentration of 0.1~0.4g / mL. APTS was added to the suspension and stirred. PdCl2 was also added to the suspension and stirred thoroughly to obtain a dispersion. The mass ratio of the Pd atomic mass in the added PdCl2 to the N-CeO2 was 1%~12%. Then, the freshly prepared NaBH4 aqueous solution was added dropwise to the dispersion with vigorous stirring. The reaction time was not less than 30min. After the reaction was completed, the obtained product was centrifuged, washed, dried and ground to obtain a formic acid decomposition hydrogen production catalyst with photoresponsive characteristics, which was recorded as PdN-CeO2.

2. Use of the catalyst according to claim 1 in photocatalytic decomposition of formic acid to produce hydrogen, characterized in that: In step (1), the molar concentration of the Ce(NO3)3 solution is 1~5 mol / L; the molar concentration of the NaOH aqueous solution is 1 mol / L; and the concentration of the CO(NH2)2 aqueous solution is 0.5~1.5 mol / L.

3. Use of the catalyst according to claim 1 in photocatalytic decomposition of formic acid to produce hydrogen, characterized in that: In step (1), the volume ratio of CO(NH2)2 aqueous solution to Ce(NO3)3 solution is (1~3):

20.

4. Use of the catalyst according to claim 1 in photocatalytic decomposition of formic acid to produce hydrogen, characterized in that: Washing in step (1) refers to washing the precipitate with deionized water and anhydrous ethanol three times respectively.

5. Use of the catalyst according to claim 1 in photocatalytic decomposition of formic acid to produce hydrogen, characterized in that: In step (2), 0.5-3.5 mL of APTS was added to the N-CeO2 suspension and stirred for 30 min.

6. Use of the catalyst according to claim 1 in photocatalytic decomposition of formic acid to produce hydrogen, characterized in that: The molar concentration of the NaBH4 aqueous solution in step (2) is 1.0~2.5mol / L.

7. Use of the catalyst according to claim 1 in photocatalytic decomposition of formic acid to produce hydrogen, characterized in that: The preparation steps of the catalyst preparation method are replaced as follows: (1) At room temperature, trisodium citrate dihydrate and CO(NH2)2 were dissolved in deionized water in succession and stirred to fully dissolve the solutes to obtain solution A; Ce(NO3)3•6H2O was then added to solution A and stirred continuously to obtain solution B. Solution B was then transferred to a high-pressure reactor and the high-pressure reactor was placed in a thermostat for heat preservation. After the heat preservation was completed, the solution was naturally cooled to room temperature to obtain solution C. PdCl2 was added to solution C and stirred thoroughly to obtain solution D. The newly prepared NaBH4 aqueous solution was then added dropwise to solution D while stirring vigorously. The reaction time was not less than 50 min. After the reaction was completed, the product was washed with anhydrous ethanol and deionized water respectively to remove impurities in the product; the washed solution was centrifuged to obtain a precipitate, and the precipitate was dried; (2) The powder obtained after drying in step (1) is calcined in an argon atmosphere at 350-550° C. for 4-6 hours to obtain a formic acid decomposition hydrogen production catalyst with photoresponsive characteristics, which is denoted as PdN-CeO2.

8. Use of the catalyst according to claim 7 in photocatalytic decomposition of formic acid to produce hydrogen, characterized in that: Step (1) Ce(NO3)3•6H2O is added to solution A and stirred for 2 hours to obtain solution B; the high-pressure reactor is placed in a constant temperature box at 180~200℃ and kept warm for 24 hours; the concentration of the newly prepared NaBH4 aqueous solution is 1.0~2.5mol / L; after the reaction is completed, the solution is washed with anhydrous ethanol and deionized water three times respectively; and the precipitate is dried at 80℃ for 5 hours.

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