Preparation Method and Application of a Cerium Oxide-Modified Platinum-Carbon Nanoparticle Electrocatalyst

Abstract

The present invention discloses a preparation method and application of a cerium oxide modified platinum-carbon nanoparticle electrocatalyst for alkaline hydrogen oxidation reaction, belonging to the technical field of electrocatalysts. The present invention does not require any complex synthesis preparation process, and a uniformly dispersed and uniform particle size cerium oxide modified platinum-carbon nanoparticle electrocatalyst is prepared by a simple and green synthesis method. The platinum-carbon catalyst is dispersed by ultrasonic, then a precursor salt solution of cerium is added, and then an alkali solution is added to make the reaction system alkaline, and a stirring reaction is carried out at room temperature for 1 to 4 hours. Then the reaction dispersion liquid is centrifuged, washed and dried. Then annealing is carried out in a suitable reducing atmosphere. Finally, an oxide platinum-carbon nanoparticle electrocatalyst is obtained. The electrocatalyst obtained by the present invention has a high electrochemically active specific surface area and is suitable for the hydrogen oxidation reaction on the anode side of an alkaline fuel cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of highly efficient oxide-modified platinum-based electrocatalysts, and relates to a preparation method and application of a cerium oxide-modified platinum-carbon nanoparticle electrocatalyst. Background Art

[0002] Nowadays, the energy on which people rely for survival is mainly traditional fossil fuels (coal, petroleum, natural gas, etc.). The overexploitation and large-scale consumption of fossil fuels not only exacerbate the energy crisis, but also lead to global warming and environmental pollution, seriously affecting human life and health. Facing the above challenges, it is urgent to develop new sustainable and environmentally friendly energy to replace fossil fuels. As a new conversion device for clean energy, fuel cells have attracted much attention. For an alkaline hydrogen-oxygen fuel cell, the overall reaction inside is (H2 + 1 / 2O2 → H2O), electrons are transferred from the anode side to the cathode side, and at the cathode side, an oxygen reduction reaction occurs (1 / 2O2 + H2O + 2e - → 2OH - ), and at the anode side, a hydrogen oxidation reaction occurs (H2 + 2OH - → 2H2O + 2e - ). To make the fuel cell operate efficiently, an effective catalyst is essential. In recent years, quite excellent catalysts have been developed for the oxygen reduction reaction on the alkaline cathode side. However, under the same conditions, the reaction rate of the alkaline hydrogen oxidation reaction is 2 - 3 orders of magnitude slower than that in acidic media. And it is necessary to study the reaction mechanism of the hydrogen oxidation reaction on the anode side to successfully obtain an efficient catalyst. It is generally believed that the alkaline HOR reaction involves the following three reaction processes: (1) H2 + M → M…2H ads (Tafel); (2) H2 + OH - + M → M…H ads + H2O + e - (Heyrovsky); (3) M…H ads + OH - → M + H2O + e - (Volmer), where H adsH atoms in the adsorbed state are represented by H, and M represents the active sites on the surface of the electrocatalyst. The oxidation of hydrogen is completed through the Tafel-Volmer or / and Heyrovsky-Volmer mechanism. Currently, there are mainly the following two views on the reaction mechanism of alkaline hydrogen oxidation: Some people believe that the adsorbed hydrogen is the only criterion for determining the reaction rate of hydrogen oxidation, while another group of researchers believe that the coexistence of adsorbed hydrogen and hydroxide ions affects the kinetics of hydrogen oxidation. In addition, the current catalyst for alkaline hydrogen oxidation is mainly platinum-carbon. Although non-platinum-based catalysts have also been explored, in terms of their comprehensive performance, platinum-carbon catalysts still rank among the top. However, the high price of platinum and its low content in the earth's crust also restrict its long-term use. Therefore, on the premise of understanding the reaction mechanism of hydrogen oxidation, it is urgent to modify the platinum-carbon catalyst for alkaline hydrogen oxidation, improve its catalytic performance, and increase its application rate.

[0003] In 2017, Zhuang et al. used 1,2-hexadecanediol as a surfactant, diphenyl ether as a reaction solvent, oleylamine as a reducing agent and solvent, and platinum acetylacetonate as the precursor salt of platinum. Under the protection of nitrogen, the reaction was carried out at 175 °C for 1 h. Then it was centrifuged and washed with ethanol. Then oleylamine and oleic acid were added to the precipitate, and the product was dispersed with chloroform. Then it was washed again. Finally, Pt nanoparticles were dispersed in chloroform. Subsequently, VXC-72 carbon was dispersed in chloroform, and the obtained Pt nanoparticles were carbon-supported by ultrasonic treatment. Finally, Pt / C was calcined in an air atmosphere at 200 °C for 5 h to remove the residual surfactant. Then PtNi / C was synthesized in a similar method. In addition, the authors also added 100 mL of 0.1 moL L -1Perchloric acid was subjected to overnight stirring treatment. The results show that the performance of the electrocatalyst is closely related to its hydrogen bond energy, but has little to do with hydroxide ions. Although the author's analysis of the experimental results has enabled people to have a deeper understanding of the mechanism of alkaline hydrogen oxidation, the performance of the catalyst has also been improved to a certain extent compared with commercial platinum-carbon, but its preparation process is extremely cumbersome, complex, and lacks direct evidence for observing the reaction process of hydrogen ions and hydroxide ions (Journal of the American Chemical Society, 2017, 139: 5156-5163). In 2022, Meng et al. prepared Pt / TiO2-CNx multicomponent complex catalysts with different anatase / rutile phases by the ethylene glycol reduction method. It was proposed that modifying carbon atoms helps to improve the dispersion and stability of metals on carbon supports. In addition, the authors also studied the relationship between the composition, structure, and performance of ultrafine Pt nanoparticles, CNx nanowires, and TiO2 cocatalysts. However, this electrocatalyst is used in acidic hydrogen oxidation reactions and does not mention alkaline hydrogen oxidation performance (Applied Surface Science, 2022, 584: 152644).

[0004] Gong et al. prepared a TiO2-Al2O3 double oxide support by the sol-gel method, and then impregnated the obtained support in a chloroplatinic acid solution, dried, and calcined to obtain a Pt / TiO2-Al2O3 catalyst, where the mass percentage content of Pt is 0.5-1.5 wt%. However, this catalyst is suitable for propane dehydrogenation to propylene, and the addition of oxides improves the catalytic dehydrogenation ability. (Gong Jinlong; Jiang Feng; Li Shuirong; Liu Gang; Zeng Liang, Tianjin University, Application No.: 201410333821.7).

[0005] In summary, there is no report on a cerium oxide-modified platinum-carbon nanoparticle electrocatalyst as an alkaline hydrogen oxidation catalyst. Its high catalytic performance has important application value for the development of alkaline fuel cells. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method and application of a cerium oxide-modified platinum-carbon nanoparticle electrocatalyst for the anodic hydrogen oxidation reaction of alkaline fuel cells in view of the deficiencies of the prior art.

[0007] To achieve the above invention purpose, the technical solution adopted by the present invention is as follows:

[0008] On the one hand, the present invention provides a preparation method of a cerium oxide-modified platinum-carbon nanoparticle electrocatalyst for the anodic hydrogen oxidation reaction of alkaline fuel cells. The method steps are as follows:

[0009] (1) Disperse platinum-carbon in a solvent and obtain a uniform dispersion by ultrasonic treatment. Then add a certain amount of precursor salt of cerium oxide to the above dispersion, and stir evenly at 15 - 35 °C for 1 - 6 h; then add a certain amount of base to convert cerium ions into cerium hydroxide and deposit it on platinum-carbon, and continue to react for 2 - 5 h; then carry out centrifugal separation and repeatedly wash with deionized water until the cerium hydroxide-modified platinum-carbon electrocatalyst becomes neutral, and dry and grind it in a blast drying oven at 50 - 70 °C. By adding different proportions of cerium oxide, oxygen vacancies are increased, thereby improving the adsorption capacity for hydroxide ions and further improving the performance of the platinum-carbon catalyst for alkaline hydrogen oxidation.

[0010] (2) React the electrocatalyst obtained in step (1) in a reducing atmosphere at 100 - 700 °C (preferably 100 - 500 °C) for 0.5 - 7 h (preferably 0.5 - 4 h). After cooling to room temperature, switch the gas to an inert atmosphere and ventilate for 0.5 - 3 h (preferably 0.5 - 1 h) to expel the remaining hydrogen in the tubular furnace, and grind again to finally obtain a cerium oxide-modified platinum-carbon nanoparticle electrocatalyst for alkaline hydrogen oxidation reaction.

[0011] The concentration of the platinum-carbon in the solvent is 1 - 20 mg / mL -1 , preferably 2 - 10 mg / mL -1 ;

[0012] The concentration of the precursor salt of cerium oxide in the solvent is 0.01 - 20 mg / mL -1 , preferably 0.01 - 5 mg / mL -1 , more preferably 0.01 - 3 mg / mL -1 ;

[0013] The concentration of the base in the solvent is 0.01 - 10 mg / mL -1 , preferably 0.01 - 5 mg / mL -1 .

[0014] In the above technical solution, further, the precursor salt of cerium oxide and the base are respectively added in the form of solutions; the concentration of the precursor salt solution of cerium oxide is 0.05 - 20 mg / mL -1 , preferably 0.05 - 8 mg / mL -1 , more preferably 0.05 - 5 mg / mL -1 ; the concentration of the base solution is 0.05 - 20 mg / mL -1 , more preferably 0.05 - 10 mg / mL -1 .

[0015] In the above technical solution, further, the cerium metal salt precursor is one, two or more of cerium nitrate hexahydrate, cerium chloride heptahydrate, cerium sulfate tetrahydrate, cerium iodide, cerium bromide, cerium ammonium nitrate, and cerium acetate.

[0016] In the above technical solution, further, the base is one, two or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, and ammonia; and the solvent is one, two or more of deionized water, ethanol, acetone, benzyl alcohol, and isopropanol.

[0017] In the above technical solution, further, the ultrasonic time in step (1) is 0.1 to 1.5 h (preferably 0.5 to 1.5 h), and the temperature is 10 to 30° C. (preferably 20 to 30° C.); the stirring rate in step (1) is 200 to 900 rpm, preferably 500 to 900 rpm.

[0018] In the above technical solution, further, in the platinum carbon, the platinum loading on the carbon carrier is 20-60%, preferably 20-40%; wherein the carbon carrier is one, two or more of carbon black, activated carbon, carbon fiber, carbon nanotubes, and graphene; the platinum precursor in the platinum carbon is one, two or more of potassium chloroplatinite, sodium chloroplatinite, potassium chloroplatinate, chloroplatinic acid, platinum dichloride, platinum tetrachloride, and platinum acetylacetonate.

[0019] In the above technical solution, further, the centrifugal speed in step (1) is 4000-10000 rpm (preferably 6000-10000 rpm), and the volume of deionized water used for each washing is 10-25 mL.

[0020] In the above technical solution, further, the drying time in step (1) is 1 to 10 hours (preferably 7 to 10 hours), and the drying temperature is 30 to 70°C, preferably 50 to 70°C.

[0021] In the above technical solution, further, the reducing atmosphere in step (2) is one or more mixed gases selected from hydrogen and hydrogen-argon mixed gas, wherein the volume ratio of hydrogen to argon in the hydrogen-argon mixed gas is 1-5:99-95.

[0022] In the above technical solution, further, the inert atmosphere of step (2) is a mixed gas of one or more of argon, nitrogen, and helium.

[0023] The second aspect of the present invention provides a cerium oxide-modified platinum carbon nanoparticle electrocatalyst prepared by the above preparation method, wherein the loading amount of the cerium oxide on the platinum carbon is 0.01 to 20 wt%, preferably 0.01 to 10 wt%.

[0024] The supported electrocatalyst prepared by the present invention has cerium oxide-modified platinum metal particles uniformly dispersed on a carbon support. The particle diameter is about 1-2 nm. The obtained nanocrystal particles are very small, with excellent size uniformity and dispersibility.

[0025] The third aspect of the present invention provides the application of a cerium oxide-modified platinum metal particle electrocatalyst in the hydrogen oxidation reaction at the anode of an alkaline fuel cell.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The present invention uses a simple and green synthesis method. At room temperature, the chemical properties of cerium metal are utilized to form a precipitate and attach it to the surface of the platinum-carbon catalyst by physical adsorption. Moreover, in a relatively low reducing atmosphere, a cerium oxide-modified platinum-carbon nanoparticle electrocatalyst is obtained without affecting the active sites of platinum in the platinum-carbon. The preparation process is simple and easy to implement. The reaction is magnetically stirred at room temperature, which is easy for batch production. By controlling the annealing temperature and the reducing atmosphere, the amount of cerium oxide generated can be controlled, and the platinum particles can be controlled within a suitable range, thereby greatly improving the performance of the platinum-carbon catalyst; greatly improving the utilization efficiency of platinum and promoting the vigorous development of alkaline fuel cells. The prepared cerium oxide-modified platinum-carbon nanoparticle electrocatalyst has high electrocatalytic activity, specific surface area and intrinsic activity, and is suitable for the hydrogen oxidation reaction at the anode of an alkaline fuel cell. Description of the Drawings

[0028] Figure 1 is the transmission electron microscope (TEM) photograph of the sample prepared in Example 1.

[0029] Figure 2 is the particle size distribution diagram of the sample prepared in Example 1;

[0030] Figure 3 is the thermogravimetric analysis (TG) curve of the sample prepared in Example 1;

[0031] Figure 4 is the X-ray diffraction (XRD) curve of the sample prepared in Example 1;

[0032] Figure 5 is the polarization curve of the sample prepared in Example 1 and commercial platinum-carbon (TZ 20wt%, Shanghai Hesen);

[0033] Figure 6 is the kinetic BV fitting curve of the polarization curve of the sample prepared in Example 1 and commercial platinum-carbon (TZ 20wt%, Shanghai Hesen);

[0034] Figure 7 is the TEM photograph of the sample prepared in Example 2;

[0035] Figure 8It is the particle size distribution diagram of the sample prepared in Example 2;

[0036] Figure 9 It is the TG curve of the sample prepared in Example 2;

[0037] Figure 10 It is the X-ray diffraction (XRD) curve of the sample prepared in Example 2;

[0038] Figure 11 It is the polarization curve of the sample prepared in Example 2 and commercial platinum-carbon (TZ 20 wt%, Shanghai Hesen);

[0039] Figure 12 It is the kinetic BV fitting curve of the polarization curve of the sample prepared in Example 2 and commercial platinum-carbon (TZ 20 wt%, Shanghai Hesen). Detailed implementation mode

[0040] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited in any way.

[0041] Example 1

[0042] Disperse 40.06 mg of platinum-carbon (TZ 20 wt%, Shanghai Hesen) in 10 mL of deionized water, and ultrasonicate for 30 min at 25 °C to obtain a uniformly dispersed carbon dispersion. Subsequently, place this system on a magnetic stirrer and stir at 22 °C and 800 rpm; then weigh 0.276 mg of cerium nitrate hexahydrate in 1 mL of deionized water, and ultrasonicate at 25 °C for 5 min to completely dissolve cerium nitrate hexahydrate. Then, add the cerium nitrate solution dropwise to the above system with a pipette and stir for 5 min; then weigh 0.4308 mg of potassium hydroxide to prepare a 1 mL solution, and ultrasonicate at 25 °C for 5 min to completely dissolve potassium hydroxide. Then, add the potassium hydroxide solution dropwise to the above system and continuously react at 22 °C and 800 rpm for 4 h. Then, transfer the reacted mixture to a centrifuge tube and centrifuge at 7000 rpm for 5 min to precipitate the reaction product from deionized water; subsequently, add 10 mL of deionized water to disperse the precipitate evenly, and centrifuge again at 7000 rpm for 5 min. Repeat this process until the supernatant becomes neutral; then place the product in a blast drying oven at 65 °C and dry for 8 h, and then grind it for standby. Then, place the product in a tubular furnace under a hydrogen-argon (V H2 :V Ar = 5:95) atmosphere, and heat to 200 °C at a heating rate of 2 °C min -1 , and keep the temperature constant at 200 °C for 2 h. After cooling to room temperature, switch the atmosphere to argon and keep it for 1 h. Grind again to finally obtain 1.0 wt% (where 1.0 wt% is m Ce / m (Ce+Pt)Platinum-carbon nanoparticles electrocatalyst modified with cerium oxide.

[0043] As Figure 1 , the TEM results showed that the obtained product was a 1.0 wt% cerium oxide modified platinum-carbon nanoparticles electrocatalyst.

[0044] As Figure 2 , it was known from particle size statistics that the particle size of platinum in 1.0 wt% cerium oxide modified platinum-carbon was about 1.8 nm.

[0045] As Figure 3 , TG determined that the metal loading of 1.0 wt% cerium oxide modified platinum-carbon in the obtained product was 26.2 wt%.

[0046] As Figure 4 , it was the X-ray diffraction (XRD) curve of the sample prepared in Example 1. It could be seen from the XRD curve that the addition of 1.0 wt% cerium oxide did not affect the crystallinity of platinum.

[0047] As Figure 5 , it was the polarization curve of the sample prepared in Example 1 and commercial platinum-carbon (TZ 20 wt%, Shanghai Hesen).

[0048] As Figure 6 , the alkaline hydrogen oxidation activity (585 A g Pt -1 ) of the 1.0 wt% cerium oxide nanoparticles electrocatalyst prepared in Example 1 was better than that of commercial platinum-carbon (320 A g Pt -1 ), and the mass specific activity was 1.83 times that of commercial platinum-carbon (TZ 20 wt%, Shanghai Hesen).

[0049] Example 2

[0050] Disperse 40.05 mg of platinum-carbon (TZ 20 wt%, Shanghai Hesen) in 10 mL of deionized water, and ultrasonicate for 40 min at 25 °C to obtain a uniformly dispersed carbon dispersion. Subsequently, place this system on a magnetic stirrer and stir at 25 °C and 600 rpm; then weigh 0.0918 mg of cerium nitrate hexahydrate in 1 mL of deionized water, and ultrasonicate at 25 °C for 5 min to completely dissolve cerium nitrate hexahydrate. Then, add the cerium nitrate hexahydrate solution dropwise to the above system using a pipette and stir for 5 min; afterwards, weigh 0.178 mg of sodium hydroxide to prepare a 1 mL solution, and ultrasonicate at 25 °C for 5 min to completely dissolve potassium hydroxide. Then, add the potassium hydroxide solution dropwise to the above system and continuously react at 25 °C and 600 rpm for 4 h. Then, transfer the reacted mixture to a centrifuge tube and centrifuge at 8000 rpm for 5 min to precipitate the reaction product from deionized water; subsequently, add 10 mL of deionized water to disperse the precipitate evenly, and centrifuge again at 8000 rpm for 5 min. Repeat this process until the supernatant becomes neutral; then place the product in a forced-air oven at 60 °C and dry for 7 h, and then grind for later use. After that, place the product in a tubular furnace under a hydrogen-argon (V H2 :V Ar = 5:95) atmosphere, and heat to 200 °C at a heating rate of 2 °C min -1 , and hold at a constant temperature of 200 °C for 2 h. After cooling to room temperature, switch the atmosphere to argon and hold for 1 h. Grind again to finally obtain a 1.0 wt% (where 1.0 wt% is m Ce(OH)3 / m (Ce(OH)3+Pt / C) ) cerium oxide-modified platinum-carbon nanoparticle electrocatalyst. The mass-specific activity of the alkaline hydrogen oxidation of this catalyst is (601 A g Pt -1 ), which is 1.88 times that of commercial 20 wt% platinum-carbon.

[0051] As Figure 7 , the TEM results show that the obtained product is a 1.0 wt% cerium oxide-modified platinum-carbon nanoparticle electrocatalyst.

[0052] As Figure 9 , by particle size statistics, the particle size of platinum in 1.0 wt% cerium oxide-modified platinum-carbon is approximately 1.35 nm.

[0053] As Figure 9 , TG determines that the metal loading of 1.0 wt% cerium oxide-modified platinum-carbon in the obtained product is 30.6 wt%.

[0054] As Figure 11 , it is the X-ray diffraction (XRD) curve of the sample prepared in Example 1. From the XRD curve, it can be seen that the addition of 1.0% cerium oxide does not affect the crystallinity of platinum.

[0055] As shown Figure 11 , it is the polarization curve of the sample prepared in Example 2 and commercial platinum carbon (TZ 20 wt%, Shanghai Hesen).

[0056] As shown Figure 12 , the alkaline hydrogen oxidation activity (561 A g Pt -1 ) of the prepared 1.0 wt% cerium oxide nanoparticle electrocatalyst is superior to that of commercial platinum carbon (320 A g Pt -1 ), and the mass specific activity is 1.75 times that of commercial platinum carbon.

[0057] Example 3

[0058] Disperse 40.12 mg of platinum carbon (TZ 20 wt%, Shanghai Hesen) in 10 mL of deionized water, and ultrasonicate for 40 min at 23 °C to obtain a uniformly dispersed carbon dispersion. Then place this system on a magnetic stirrer and stir at 23 °C and 600 rpm; then weigh 1.12 mg of cerium chloride heptahydrate in 1 mL of deionized water, and ultrasonicate at 23 °C for 6 min to completely dissolve cerium chloride heptahydrate. Then add the cerium chloride heptahydrate solution dropwise to the above system with a pipette and stir for 5 min; then weigh 3.244 mg of potassium hydroxide to prepare a 2 mL solution, and ultrasonicate at 23 °C for 5 min to completely dissolve potassium hydroxide. Then add the potassium hydroxide solution dropwise to the above system and continuously react at the conditions of 23 °C and 600 rpm for 3 h. Then, transfer the reacted mixture to a centrifuge tube and centrifuge at 8000 rpm for 5 min to precipitate the reaction product from deionized water; then add 10 mL of deionized water to disperse the precipitate evenly, and centrifuge again at 8000 rpm for 5 min. Repeat this process until the supernatant becomes neutral; then place the product in a blast drying oven at 65 °C and dry for 8 h, and then grind it for standby. Then place the product in a tubular furnace under a hydrogen-argon (V H2 :V Ar = 5:95) atmosphere and heat it to 200 °C at a heating rate of 2 °C min -1 , and keep it at a constant temperature of 200 °C for 2 h. After cooling to room temperature, switch the atmosphere to argon and keep it for 1 h. Grind again to finally obtain a 5.0 wt% (where 5.0 wt% is m Ce / m (Ce+Pt) ) cerium oxide-modified platinum carbon nanoparticle electrocatalyst. The mass specific activity of this catalyst for alkaline hydrogen oxidation is (520 A g Pt -1 ), which is 1.63 times that of commercial 20 wt% platinum carbon.

[0059] Example 4

[0060] Disperse 40.06 mg of platinum-carbon (TZ 20 wt%, Shanghai Hesen) in 10 mL of deionized water, and ultrasonicate for 30 min at 25 °C to obtain a uniformly dispersed carbon dispersion. Subsequently, place this system on a magnetic stirrer and stir at 25 °C and 600 rpm; then weigh 0.138 mg of cerium nitrate hexahydrate in 1 mL of deionized water, and ultrasonicate at 25 °C for 5 min to completely dissolve cerium nitrate hexahydrate. Then, add the cerium nitrate solution dropwise to the above system using a pipette and stir for 5 min; then weigh 0.2154 mg of potassium hydroxide to prepare a 1 mL solution, and ultrasonicate at 25 °C for 5 min to completely dissolve potassium hydroxide. Then, add the potassium hydroxide solution dropwise to the above system and continuously react at 25 °C and 600 rpm for 2 h. Then, transfer the reaction mixture to a centrifuge tube and centrifuge at 8000 rpm for 5 min to precipitate the reaction product from deionized water; subsequently, add 10 mL of deionized water to disperse the precipitate evenly, and centrifuge again at 8000 rpm for 5 min. Repeat this process until the supernatant becomes neutral; then place the product in a blast drying oven at 60 °C and dry for 7 h, and then grind for later use. Then, place the product in a tubular furnace under a hydrogen-argon (V H2 :V Ar = 5:95) atmosphere, and heat to 200 °C at a heating rate of 2 °C min -1 , and keep the temperature constant for 1 h. After cooling to room temperature, switch the atmosphere to argon and keep it for 1 h. Grind again to finally obtain a 0.5 wt% (where 0.5 wt% is m Ce / m (Ce+Pt) ) cerium oxide-modified platinum-carbon nanoparticle electrocatalyst.

[0061] Example 5

[0062] Disperse 40.06 mg of platinum carbon (TZ 20 wt%, Shanghai Hesen) in 10 mL of deionized water, and ultrasonicate for 30 min at 22 °C to obtain a uniformly dispersed carbon dispersion. Subsequently, place this system on a magnetic stirrer and stir at 22 °C and 800 rpm. Then, weigh 0.276 mg of cerium nitrate hexahydrate in 1 mL of deionized water, and ultrasonicate for 5 min at 22 °C to completely dissolve cerium nitrate hexahydrate. Then, add the cerium nitrate solution dropwise to the above system using a pipette and stir for 5 min. After that, weigh 0.4308 mg of potassium hydroxide to prepare a 1 mL solution, and ultrasonicate for 5 min at 22 °C to completely dissolve potassium hydroxide. Then, add the potassium hydroxide solution dropwise to the above system and continuously react at 22 °C and 800 rpm for 4 h. Then, transfer the reacted mixture to a centrifuge tube and centrifuge at 7000 rpm for 5 min to precipitate the reaction product from deionized water. Subsequently, add 10 mL of deionized water to disperse the precipitate evenly, and centrifuge again at 7000 rpm for 5 min. Repeat this process until the supernatant is neutral. Then, place the product in a forced-air oven at 65 °C and dry for 8 h, and then grind it for later use. After that, place the product in a tubular furnace under a hydrogen-argon (V H2 :V Ar = 5:95) atmosphere, and heat it to 300 °C at a heating rate of 2 °C min -1 , and keep it at a constant temperature for 2 h. After cooling to room temperature, switch the atmosphere to argon and keep it for 1 h. Grind it again to finally obtain a 1.0 wt% (where 1.0 wt% is m Ce / m (Ce+Pt) ) cerium oxide-modified platinum carbon nanoparticle electrocatalyst. The mass-specific activity of the alkaline hydrogen oxidation of this catalyst is (391 A g Pt -1 ).

[0063] Example 6

[0064] Disperse 40.06 mg of platinum-carbon (TZ 20 wt%, Shanghai Hesen) in 10 mL of deionized water, and ultrasonicate for 30 min at 22 °C to obtain a uniformly dispersed carbon dispersion. Subsequently, place this system on a magnetic stirrer and stir at 22 °C and 800 rpm; then weigh 1.38 mg of cerium nitrate hexahydrate in 1 mL of deionized water, ultrasonicate at 22 °C for 5 min to completely dissolve cerium nitrate hexahydrate, and then add the cerium nitrate solution dropwise to the above system with a pipette and stir for 5 min; then weigh 2.15 mg of potassium hydroxide to prepare a 1 mL solution, ultrasonicate at 22 °C for 5 min to completely dissolve potassium hydroxide, and then add the potassium hydroxide solution dropwise to the above system. Under the conditions of 22 °C and 800 rpm, continuously react for 4 h. Then, transfer the reacted mixture to a centrifuge tube and centrifuge at 7000 rpm for 5 min to precipitate the reaction product from deionized water; subsequently, add 10 mL of deionized water to disperse the precipitate evenly, and centrifuge again at 7000 rpm for 5 min. Repeat this process until the supernatant is neutral; then place the product in a blast drying oven at 65 °C and dry for 8 h, and then grind for standby. Obtain a cerium hydroxide-modified platinum-carbon nanoparticle electrocatalyst with 7.75 wt% (where 7.75 wt% is m Ce / m (Ce+Pt) ). The mass-specific activity of this catalyst for the alkaline hydrogen oxidation reaction is (385 A g Pt -1 ).

[0065] Experimental Example 7

[0066] Disperse 80 mg of VXC-72 carbon in 10 mL of deionized water, and ultrasonicate for 40 min at 25 °C to obtain a uniformly dispersed carbon dispersion; then add 42.55 mg of potassium chloroplatinate solution (10 mg mL -1 ) to the above dispersion, and ultrasonicate at 25 °C for another 30 min to completely dissolve the metal salt. Place the above system in a water bath and stir at 0 °C and 600 rpm for 5 min. Then add 46.54 mg (10 mg mL -1 ) of sodium borohydride solution, and then continuously stir at 600 rpm for 0.5 h. Then, first separate the solid and liquid with a vacuum filtration funnel and wash with a large amount of deionized water until the black solid is neutral. Then dry the catalyst in a blast drying oven at 65 °C for 8 h, grind, and set aside to obtain self-made platinum-carbon.

[0067] Disperse 40.05 mg of self-made platinum-carbon in 10 mL of deionized water, and ultrasonicate for 35 min at 25 °C to obtain a uniformly dispersed self-made platinum-carbon dispersion. Subsequently, place this system on a magnetic stirrer and stir at 25 °C and 800 rpm; then weigh 0.276 mg of cerium nitrate tetrahydrate in 1 mL of deionized water, and ultrasonicate for 5 min at 25 °C to completely dissolve cerium nitrate hexahydrate. Then, add the cerium nitrate solution dropwise to the above system using a pipette and stir for 5 min; then weigh 0.4308 mg of potassium hydroxide to prepare a 1 mL solution, ultrasonicate for 5 min to completely dissolve potassium hydroxide, and then add the potassium hydroxide solution dropwise to the above system. Under the conditions of 25 °C and 600 rpm, continuously react for 4 h. Then, transfer the reacted mixture to a centrifuge tube and centrifuge at 8000 rpm for 5 min to precipitate the reaction product from the deionized water; then add 10 mL of deionized water to disperse the precipitate evenly, and centrifuge again at 8000 rpm for 5 min. Repeat this process until the supernatant is neutral; then place the product in a forced-air oven at 65 °C and dry for 8 h, and then grind for later use. After that, place the product in a tubular furnace under a hydrogen-argon (V H2 :V Ar = 5:95) atmosphere, and heat to 200 °C at a heating rate of 2 °C / min<U+ -1 , and hold at a constant temperature for 2 h. After cooling to room temperature, switch the atmosphere to argon and hold for 1 h. Grind again to finally obtain a 1.0 wt% (where 1.0 wt% is m Ce / m (Ce+Pt) ) cerium oxide-modified self-made platinum-carbon nanoparticle electrocatalyst.

[0068] For any person skilled in the art, without departing from the scope of the technical solution of the present invention, many possible changes and modifications can be made to the technical solution of the present invention by using the technical content disclosed above, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A preparation method of a cerium oxide modified platinum-carbon nanoparticle electrocatalyst, characterized in that, The method steps are as follows: (1) Disperse platinum-carbon in a solvent and ultrasonically obtain a uniform dispersion liquid. Then, add a cerium precursor salt and a base to the above dispersion liquid, and stir and react at 15 - 35 °C for 1 - 6 h to obtain a reacted mixture; then perform centrifugal separation and washing until the cerium hydroxide-modified platinum-carbon electrocatalyst becomes neutral, and then dry and grind it; (2) React the electrocatalyst obtained in step (1) in a reducing atmosphere at 100 - 300 °C for 0.5 - 7 h. After cooling to room temperature, switch the gas to an inert atmosphere and ventilate for 0.5 - 3 h, and grind again to finally obtain a cerium oxide-modified platinum-carbon nanoparticle electrocatalyst for alkaline hydrogen oxidation reaction; the cerium oxide-modified platinum-carbon nanoparticle electrocatalyst is applicable to the hydrogen oxidation reaction on the anode side of an alkaline fuel cell; The concentration of the platinum-carbon in the solvent is 1 to 20 mg / mL -1 ; The concentration of the cerium precursor salt in the solvent is 0.01 to 20 mg / mL -1 ; The concentration of the alkali in the solvent is 0.01 to 10 mg / mL -1 ; The solvent is deionized water; The reducing atmosphere in step (2) is a hydrogen-argon mixture, and the volume ratio of hydrogen to argon in the hydrogen-argon mixture is 1 - 5:99 - 95.

2. The preparation method according to claim 1, wherein, The cerium precursor salt is one or more of cerium nitrate hexahydrate, cerium chloride heptahydrate, cerium sulfate tetrahydrate, cerium iodide, cerium bromide, ammonium cerium nitrate, and cerium acetate.

3. The preparation method according to claim 1, characterized in that, The base is one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, and ammonia water.

4. The preparation method according to claim 1, characterized in that, The ultrasonic time in step (1) is 0.1 - 1.5 h, and the temperature is 10 - 30 °C; the stirring rate in step (1) is 200 - 900 rpm.

5. The preparation method according to claim 1, characterized in that, In the platinum-carbon, the loading amount of platinum on the carbon support is 20 - 60%; the carbon support is one or more of carbon black, activated carbon, carbon fiber, carbon nanotube, and graphene; the precursor of platinum in the platinum-carbon is one or more of potassium chloroplatinate, sodium chloroplatinate, potassium chloroplatinate, chloroplatinic acid, platinum dichloride, platinum tetrachloride, and platinum acetylacetonate.

6. The preparation method according to claim 1, characterized in that, The drying time in step (1) is 1 - 10 h, and the drying temperature is 30 - 70 °C.

7. The preparation method according to claim 1, characterized in that The inert atmosphere in step (2) is one or a mixture of gases such as argon, nitrogen, and helium.

8. A cerium oxide-modified platinum-carbon nanoparticle electrocatalyst prepared by the preparation method according to any one of claims 1 - 7.

9. The cerium oxide modified platinum-carbon nanoparticle electrocatalyst according to claim 8, wherein In the cerium oxide-modified platinum-carbon nanoparticle electrocatalyst, the loading amount of cerium oxide on the platinum-carbon is 0.01 - 20 wt%.

Images