Preparation method and application of Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst

Abstract

This invention discloses a method for preparing and applying an Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst. The method uses carbon cloth as a substrate, europium inorganic salt as the europium source, nickel inorganic salt as the nickel source, amino acids as rare earth anchoring agents, ammonium fluoride as a precipitant, and urea as a reducing agent. A carbon cloth-supported Eu-doped Ni(OH)2 precursor is synthesized via a hydrothermal reaction, and the catalyst is finally prepared by a low-temperature phosphating process in an Ar / H2 atmosphere. This invention dops europium into nickel metaphosphate; the synergistic effect of europium and nickel improves the catalytic activity and stability of the catalyst. Furthermore, the catalyst exhibits good morphology retention and high selectivity for the oxygen evolution reaction (OER), showing promising market prospects.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalyst preparation technology, specifically relating to a method for preparing and applying an Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst. Background Technology

[0002] With social development, energy shortages and environmental problems are becoming increasingly serious, leading to a growing demand for clean energy sources such as wind, hydro, and solar power. Among these, hydrogen energy, with its high energy density, abundant reserves, and wide range of applications, has attracted widespread attention. Currently, the main industrial methods for producing hydrogen include high-temperature cracking of natural gas, water gasification, and water electrolysis. Water electrolysis, using water as a raw material, offers advantages such as environmental friendliness and the production of non-toxic and pollution-free products, and is considered to have broad application prospects.

[0003] The water electrolysis reaction consists of HER and OER. Currently, the most ideal catalysts for HER and OER are noble metal Pt-based and RuO2 / IrO2 materials, respectively. However, the scarcity, high cost, slow kinetics, and susceptibility to poisoning of noble metal catalysts greatly limit their large-scale application. Oxygen evolution reaction (OER) is an important component of water electrolysis, and Ni-based phosphate catalysts are a promising class of water electrolysis catalysts. Although they possess advantages such as environmental friendliness, abundant reserves, and easily tunable electronic structures, their poor intrinsic activity and slow kinetics make them unsuitable for practical applications in water electrolysis. Therefore, the research and development of inexpensive and efficient non-noble metal Ni-based phosphate catalysts is crucial. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention aims to provide a method for preparing and applying Eu-doped Ni(PO3)2 porous nanosheet electrocatalysts. The Eu-doped Ni(PO3)2 porous nanosheet electrocatalysts prepared by this invention using hydrothermal and low-temperature phosphating methods exhibit better OER electrocatalytic activity and stability than commercial RuO2.

[0005] To address the problems in the existing technology, the technical solution adopted by this invention is as follows:

[0006] A method for preparing Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst involves using hydrophilic carbon cloth as a substrate, europium inorganic salt as the europium source, nickel inorganic salt as the nickel source, amino acid as a rare earth anchoring agent, ammonium fluoride as a precipitant, and urea as a reducing agent. The carbon cloth-supported Eu-doped Ni(OH)2 precursor is synthesized via hydrothermal reaction, and the catalyst is finally prepared by a low-temperature phosphating process in an Ar / H2 atmosphere.

[0007] The preparation method of the above-mentioned Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst includes the following steps:

[0008] Step 1, Preparation of Eu-doped Ni(OH)₂ precursor

[0009] Europium salt, nickel salt, urea, ammonium fluoride, and amino acids are mixed, wherein the molar ratio of europium salt, nickel salt, urea, and ammonium fluoride is 0.05–0.1:1.2–3:1–5:2–3, and the content of amino acids should exceed 2% of the molar content of the system. The mixture is dissolved in water, and pretreated hydrophilic carbon cloth is added. A hydrothermal reaction is carried out at a reaction temperature of 100–150°C for 8–12 hours. After the reaction is completed, the mixture is washed and dried to obtain an Eu-doped Ni(OH)₂ precursor, wherein the molar amount of nickel salt corresponding to each square centimeter of hydrophilic carbon cloth is 0.15–0.23 mmol.

[0010] Step 2, Preparation of Eu-Ni(PO3)2

[0011] The Eu-doped Ni(OH)2 precursor from step 1 is placed in a quartz boat downstream of the Ar / H2 gas flow, and the phosphorus source is placed in a quartz boat upstream of the Ar / H2 gas flow. After the air in the tube furnace is exhausted, the temperature is raised to 250-450℃ and calcined for 30-150 minutes, with continuous gas flow during the calcination process, to obtain the carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0012] Preferably, the amino acid in step 1 is lysine or arginine. The amino group and other groups in the amino acid attract each other to form coordination with europium ions, and the resulting clusters can effectively embed into the vacancies of Ni(OH)2 supported on carbon cloth, thereby ensuring that rare earth phosphates are not formed during the subsequent phosphating process, but rather metaphosphates are formed.

[0013] Preferably, the pretreatment steps of the hydrophilic carbon cloth in step 1 are as follows: the cut hydrophilic carbon cloth is ultrasonically cleaned in ethanol, then rinsed with deionized water, then acidified with dilute acid for 12 hours, and finally rinsed with deionized water until neutral, and then set aside to remove oil and oxide layer from the surface of the hydrophilic carbon cloth.

[0014] More preferably, the dilute acid is a nitric acid solution of 1–3 mol / L.

[0015] Preferably, the europium salt in step 1 is europium nitrate hexahydrate or europium chloride hexahydrate; the nickel salt is nickel nitrate hexahydrate, nickel chloride hexahydrate, or nickel sulfate hexahydrate.

[0016] Preferably, the phosphorus source in step 2 is sodium hypophosphite or potassium hypophosphite, and the ratio of the mass of phosphorus source required for calcination of a unit carbon cloth-loaded sample to the area of ​​the carbon cloth should not be less than 0.06 g / cm³. -2 .

[0017] Preferably, the heating rate during calcination in step 2 is 1–5 °C / min. Low-temperature phosphating technology has advantages such as low energy requirements, controllable heating rate, and low toxicity of byproducts. The controllable heating rate helps maintain the morphology of the catalyst during sintering, resulting in a larger specific surface area and improved catalytic performance.

[0018] The Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst prepared by the above method is used as an anode catalyst in an anion exchange membrane water electrolysis device.

[0019] Invention Mechanism:

[0020] Rare earth element Eu has attracted increasing attention for its variable coordination number and unique chemical and electronic properties of the 4f-subshell orbital, making it valuable for adjusting electronic structure and improving the catalytic performance of transition metal-based materials. This invention involves doping Eu with rare earth element Eu to Eu-Ni(PO3)2, optimizing the electronic structure of the Eu-Ni(PO3)2 catalyst and the adsorption energy of reaction intermediate species, lowering the energy barrier for the overall water splitting reaction, and effectively improving the catalyst's catalytic activity.

[0021] Beneficial effects:

[0022] Compared with existing technologies, the preparation method and application of the Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst of the present invention have the following significant advantages:

[0023] (1) The catalyst of the present invention is doped with europium in nickel metaphosphate. Under the synergistic effect of nickel and europium, the catalytic activity and stability of the catalyst are improved.

[0024] (2) The Eu-Ni(PO3)2 supported on the surface of hydrophilic carbon cloth is in the form of porous sheets. This structure provides a huge specific surface area and abundant active sites, which further improves the catalytic activity of the catalyst.

[0025] (3) The method of the present invention is simple and quick to operate and can be mass-produced. The low-temperature phosphating treatment can better anchor rare earth atoms, and the resulting catalyst has stable structure and high efficiency. Attached Figure Description

[0026] Figure 1 The images are high-resolution scanning electron microscope (HRSEM) images of the precursor obtained in step (2) of Example 2, where (a) is a 4 μm scale bar and (b) is a 2 μm scale bar.

[0027] Figure 2 HRSEM images of the Eu-Ni(PO3)2 catalyst prepared in Example 2, where (a) is a 20 μm scale bar and (b) is a 10 μm scale bar;

[0028] Figure 3 Transmission electron microscope (TEM) image of the Eu-Ni(PO3)2 catalyst prepared in Example 2;

[0029] Figure 4 The X-ray diffraction (XRD) pattern of the Eu-Ni(PO3)2 catalyst prepared in Example 2;

[0030] Figure 5 X-ray photoelectron spectra (XPS) of the Eu-Ni(PO3)2 catalyst prepared in Example 2;

[0031] Figure 6 The OER curves of the Eu-Ni(PO3)2 catalyst prepared in Example 2 and the commercially available RuO2 catalyst in 1M KOH solution are compared.

[0032] Figure 7 Stability test curve of the Eu-Ni(PO3)2 catalyst prepared in Example 2 in 1M KOH solution. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the embodiments.

[0034] Example 1

[0035] A method for preparing a carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst includes the following steps:

[0036] (1) The 2cm*4cm hydrophilic carbon cloth was ultrasonically cleaned in ethanol and deionized water in sequence, then treated in a 2mol / L dilute nitric acid solution for 12h to remove the oxide film on the surface, then rinsed with deionized water until neutral, and dried at 60℃ for later use.

[0037] (2) Weigh 0.08 mmol europium nitrate, 1.2 mmol nickel nitrate, 2 mmol urea, 0.5 g lysine and 2 mmol ammonium fluoride and dissolve them in 30 mL deionized water. Stir well and add the hydrophilic carbon cloth treated in step (1). React in a reactor at 150 °C for 8 h. After the reaction is complete, wash and dry to obtain Eu-doped Ni(OH)2 precursor.

[0038] (3) In a tube furnace, the carbon treated in step 1 is arranged in a quartz boat upstream of the gas flow and downstream of the Ar / H2 gas flow. 2g of potassium hypophosphite is placed in another quartz boat as a phosphorus source and upstream of the gas flow. Ar / H2 gas is introduced to purge the air in the tube furnace. Ar / H2 is continued to be introduced and the temperature is raised to 300℃ at a heating rate of 2℃ / min under the Ar / H2 atmosphere. The furnace is calcined for 90min to obtain carbon cloth supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0039] Example 2

[0040] A carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst, the preparation method of which includes the following steps:

[0041] (1) The 2cm*4cm hydrophilic carbon cloth was ultrasonically cleaned in ethanol and deionized water in sequence, then treated in a 3mol / L dilute nitric acid solution for 12h to remove the oxide film on the surface, then rinsed with deionized water until neutral, and dried at 60℃ for later use.

[0042] (2) Weigh 0.1 mmol europium nitrate, 1.2 mmol nickel nitrate, 8 mmol urea, 0.2 g lysine and 2 mmol ammonium fluoride and dissolve them in 30 mL deionized water and stir thoroughly. Add the hydrophilic carbon cloth treated in step (1) and react in a reactor at 120 °C for 12 h. After the reaction is complete, wash and dry to obtain Eu-doped Ni(OH)2 precursor.

[0043] (3) In a tube furnace, the carbon processed in step 1 is arranged in a quartz boat upstream of the gas flow and downstream of the Ar / H2 gas flow. 0.5g of sodium hypophosphite is placed in another quartz boat as a phosphorus source and upstream of the gas flow. Ar / H2 gas is introduced to purge the air in the tube furnace. Ar / H2 is continued to be introduced and the temperature is raised to 450°C at a heating rate of 2°C / min in the Ar / H2 atmosphere. The furnace is calcined for 150min to obtain carbon cloth supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0044] Performance Characterization

[0045] (1) The catalyst prepared in Example 2 was physically characterized by HRSEM, TEM, XRD and other methods.

[0046] By HRSEM ( Figure 1 , Figure 2 The photos show that the prepared Ni(PO3)2 nanosheets are uniformly distributed on the surface of the carbon cloth, arranged neatly, and have similar morphologies. This proves that the doping of Eu and the subsequent calcination process did not affect the main morphology of the material, further confirming the good stability of the material.

[0047] By TEM ( Figure 3 The photos also clearly show the two-dimensional sheet-like morphology of Eu-Ni(PO3)2 nanocrystals, with an average particle size of approximately 500 nm.

[0048] From XRD patterns ( Figure 4It can be seen that the diffraction peaks of the catalyst are completely consistent with the standard card of Ni(PO3)2 (JCPDS standard card #28-0708) and no obvious Eu diffraction signal is found. This further indicates that the Eu element enters Ni(PO3)2 in the form of doping, and the doping of Eu does not change the phase and crystallographic information of Ni(PO3)2.

[0049] From XPS maps ( Figure 5 The presence of Eu, Ni, P and O signals in the Eu-Ni(PO3)2 nanoneedles further corroborates the existence of Eu.

[0050] Example 3

[0051] The carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst of the present invention includes the following steps:

[0052] (1) The 2cm*4cm hydrophilic carbon cloth was ultrasonically cleaned in ethanol and deionized water in sequence, then treated in a 2mol / L dilute nitric acid solution for 12h to remove the oxide film on the surface, then rinsed with deionized water until neutral, and dried at 60℃ for later use.

[0053] (2) Weigh 0.05 mmol europium nitrate, 2.4 mmol nickel nitrate, 1 mmol urea, 0.4 g lysine and 3 mmol ammonium fluoride and dissolve them in 30 mL deionized water and stir thoroughly. Add the hydrophilic carbon cloth treated in step (1) and react in a reactor at 120 °C for 12 h. After the reaction is complete, wash and dry to obtain Eu-doped Ni(OH)2 precursor.

[0054] (3) In a tube furnace, the carbon processed in step 1 is arranged in a quartz boat upstream of the gas flow and downstream of the Ar / H2 gas flow. 0.8g of sodium hypophosphite is placed in another quartz boat as a phosphorus source and upstream of the gas flow. Ar / H2 gas is introduced to purge the air in the tube furnace. Ar / H2 is continued to be introduced and the temperature is raised to 350℃ at a heating rate of 2℃ / min under the Ar / H2 atmosphere. The furnace is calcined for 90min to obtain carbon cloth supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0055] Example 4

[0056] A method for preparing a carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst includes the following steps:

[0057] (1) The 2cm*4cm hydrophilic carbon cloth was ultrasonically cleaned in ethanol and deionized water in sequence, then treated in a 2mol / L dilute nitric acid solution for 12h to remove the oxide film on the surface, then rinsed with deionized water until neutral, and dried at 60℃ for later use.

[0058] (2) Weigh 0.1 mmol europium nitrate, 2 mmol nickel nitrate, 2 mmol urea, 0.6 g arginine and 2.5 mmol ammonium fluoride and dissolve them in 30 mL deionized water. Stir well and add the hydrophilic carbon cloth treated in step (1). React in a reactor at 100 °C for 9 h. After the reaction is complete, wash and dry to obtain Eu-doped Ni(OH)2 precursor.

[0059] (3) In a tube furnace, the carbon processed in step 1 is arranged in a quartz boat upstream of the gas flow and downstream of the Ar / H2 gas flow. 1.6g of sodium hypophosphite is placed in another quartz boat as a phosphorus source and upstream of the gas flow. Ar / H2 gas is introduced to purge the air in the tube furnace. Ar / H2 is continued to be introduced and the temperature is raised to 350℃ at a heating rate of 1.5℃ / min under the Ar / H2 atmosphere. The furnace is calcined for 120min to obtain carbon cloth supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0060] Example 5

[0061] A method for preparing a carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst includes the following steps:

[0062] (1) The 2cm*4cm hydrophilic carbon cloth was ultrasonically cleaned in ethanol and deionized water in sequence, then treated in a 1mol / L dilute nitric acid solution for 12h to remove the oxide film on the surface, then rinsed with deionized water until neutral, and dried at 60℃ for later use.

[0063] (2) Weigh 0.06 mmol europium nitrate, 2 mmol nickel nitrate, 3 mmol urea, 0.3 g lysine and 2 mmol ammonium fluoride and dissolve them in 30 mL deionized water and stir thoroughly. Add the hydrophilic carbon cloth treated in step (1) and react in a reactor at 120 °C for 12 h. After the reaction is complete, wash and dry to obtain Eu-doped Ni(OH)2 precursor.

[0064] (3) In a tube furnace, the carbon processed in step 1 is arranged in a quartz boat upstream of the gas flow and downstream of the Ar / H2 gas flow. 1g of sodium hypophosphite is placed in another quartz boat as a phosphorus source and upstream of the gas flow. Ar / H2 gas is introduced to purge the air in the tube furnace. Ar / H2 is continued to be introduced and the temperature is raised to 400℃ at a heating rate of 1℃ / min under the Ar / H2 atmosphere. The furnace is calcined for 150min to obtain carbon cloth supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0065] Example 6

[0066] A carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst, the preparation method of which includes the following steps:

[0067] (1) The 2cm*4cm hydrophilic carbon cloth was ultrasonically cleaned in ethanol and deionized water in sequence, then treated in a 1mol / L dilute nitric acid solution for 12h to remove the oxide film on the surface, then rinsed with deionized water until neutral, and dried at 60℃ for later use.

[0068] (2) Weigh 0.06 mmol europium nitrate, 2 mmol nickel nitrate, 3 mmol urea, 0.5 g arginine and 2 mmol ammonium fluoride and dissolve them in 30 mL deionized water and stir thoroughly. Add the hydrophilic carbon cloth treated in step (1) and react in a reactor at 120 °C for 8 h. After the reaction is complete, wash and dry to obtain Eu-doped Ni(OH)2 precursor.

[0069] (3) In a tube furnace, the carbon treated in step 1 is arranged in a quartz boat upstream of the gas flow and downstream of the Ar / H2 gas flow. 1.2g of potassium hypophosphite is placed in another quartz boat as a phosphorus source and upstream of the gas flow. Ar / H2 gas is introduced to purge the air in the tube furnace. Ar / H2 is continued to be introduced and the temperature is raised to 450℃ at a heating rate of 4℃ / min under the Ar / H2 atmosphere. The furnace is calcined for 150min to obtain carbon cloth supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0070] Example 7

[0071] A method for preparing a carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst includes the following steps:

[0072] (1) The 2cm*4cm hydrophilic carbon cloth was ultrasonically cleaned in ethanol and deionized water in sequence, then treated in a 1mol / L dilute nitric acid solution for 12h to remove the oxide film on the surface, then rinsed with deionized water until neutral, and dried at 60℃ for later use.

[0073] (2) Weigh 0.06 mmol europium chloride, 1.2 mmol nickel sulfate, 3 mmol urea, 0.1 g lysine and 2.5 mmol ammonium fluoride and dissolve them in 30 mL deionized water and stir thoroughly. Add the hydrophilic carbon cloth treated in step (1) and react in a reactor at 100 °C for 8 h. After the reaction is complete, wash and dry to obtain Eu-doped Ni(OH)2 precursor.

[0074] (3) In a tube furnace, the carbon treated in step 1 is placed in a quartz boat upstream of the gas flow and downstream of the Ar / H2 gas flow. 1.2g of potassium hypophosphite is placed in another quartz boat as a phosphorus source and upstream of the gas flow. Ar / H2 gas is introduced to purge the air in the tube furnace. Ar / H2 is continued to be introduced and the temperature is raised to 400℃ at a heating rate of 5℃ / min under the Ar / H2 atmosphere. The furnace is calcined for 100min to obtain carbon cloth supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0075] Example 8

[0076] A method for preparing a carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst includes the following steps:

[0077] (1) The 2cm*4cm hydrophilic carbon cloth was ultrasonically cleaned in ethanol and deionized water in sequence, then treated in a 3mol / L dilute nitric acid solution for 12h to remove the oxide film on the surface, then rinsed with deionized water until neutral, and dried at 60℃ for later use.

[0078] (2) Weigh 0.08 mmol europium nitrate, 3 mmol nickel nitrate, 1 mmol urea, 0.4 g lysine and 2.5 mmol ammonium fluoride and dissolve them in 30 mL deionized water and stir thoroughly. Add the hydrophilic carbon cloth treated in step (1) and react in the reactor at 150 °C for 8 h. After the reaction is complete, wash and dry the product for later use.

[0079] (3) In a tube furnace, the carbon processed in step 1 is arranged in a quartz boat upstream of the gas flow and downstream of the Ar / H2 gas flow. 1g of sodium hypophosphite is placed in another quartz boat as a phosphorus source and upstream of the gas flow. Ar / H2 gas is introduced to purge the air in the tube furnace. Ar / H2 is continued to be introduced and the temperature is raised to 300℃ at a heating rate of 4℃ / min under the Ar / H2 atmosphere. The calcination is carried out for 60min to obtain carbon cloth supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0080] Example 9

[0081] A method for preparing a carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst includes the following steps:

[0082] (1) The 2cm*4cm hydrophilic carbon cloth was ultrasonically cleaned in ethanol and deionized water in sequence, then treated in a 1mol / L dilute nitric acid solution for 12h to remove the oxide film on the surface, then rinsed with deionized water until neutral, and dried at 60℃ for later use.

[0083] (2) Weigh 0.08 mmol europium nitrate, 2 mmol nickel nitrate, 1 mmol urea, 0.1 g lysine and 3 mmol ammonium fluoride and dissolve them in 30 mL deionized water and stir thoroughly. Add the hydrophilic carbon cloth treated in step (1) and react in a reactor at 120 °C for 10 h. After the reaction is complete, wash and dry to obtain Eu-doped Ni(OH)2 precursor.

[0084] (3) In a tube furnace, the carbon processed in step 1 is arranged in a quartz boat upstream of the gas flow and downstream of the Ar / H2 gas flow. 0.5g of sodium hypophosphite is placed in another quartz boat as a phosphorus source and upstream of the gas flow. Ar / H2 gas is introduced to purge the air in the tube furnace. Ar / H2 is continued to be introduced and the temperature is raised to 250℃ at a heating rate of 2.5℃ / min under the Ar / H2 atmosphere. The furnace is calcined for 90min to obtain carbon cloth supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0085] Example 10

[0086] A method for preparing a carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst includes the following steps:

[0087] (1) The 2cm*4cm hydrophilic carbon cloth was ultrasonically cleaned in ethanol and deionized water in sequence, then treated in a 1mol / L dilute nitric acid solution for 12h to remove the oxide film on the surface, then rinsed with deionized water until neutral, and dried at 60℃ for later use.

[0088] (2) Weigh 0.08 mmol europium nitrate, 3 mmol nickel nitrate, 8 mmol urea, 0.3 g lysine and 2.5 mmol ammonium fluoride and dissolve them in 30 mL deionized water and stir thoroughly. Add the hydrophilic carbon cloth treated in step (1) and react in a reactor at 120 °C for 9 h. After the reaction is complete, wash and dry to obtain Eu-doped Ni(OH)2 precursor.

[0089] (3) In a tube furnace, the carbon processed in step 1 is placed in a quartz boat upstream of the gas flow and downstream of the Ar / H2 gas flow. 1.5g of sodium hypophosphite is placed in another quartz boat as a phosphorus source and upstream of the gas flow. Ar / H2 gas is introduced to purge the air in the tube furnace. Ar / H2 is continued to be introduced and the temperature is raised to 300℃ at a heating rate of 1℃ / min under the Ar / H2 atmosphere. The furnace is calcined for 60min to obtain carbon cloth supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

[0090] Comparative Example 1

[0091] In step (2), europium salt is not added, and the rest is the same as in Example 2, to obtain a carbon cloth supported Ni(PO3)2 oxygen evolution electrocatalyst.

[0092] Catalytic performance tests of Example 2, Comparative Example 1, and RuO2 catalyst

[0093] Figure 6 The oxygen evolution (OER) curves of the catalyst prepared in Example 2, the catalyst prepared in Comparative Example 1, and a commercially available RuO2 catalyst (from Shanghai Dibai Biotechnology Co., Ltd.) in 1M KOH solution are shown in the figure. It can be seen from the figure that the catalyst prepared in Example 2 exhibits the best OER at a current density of 10 mA·cm⁻¹. -2 The overpotential was only 272 mV, which is better than that of commercially available RuO2 catalyst (340 mV) and comparative example 1 catalyst (325 mV) without Eu doping.

[0094] Depend on Figure 7 The chronopotential (CP) test curve of the catalyst prepared in Example 2 shows that after long-range constant current density testing, the catalyst still maintains a relatively stable potential curve in an alkaline environment, indicating good stability.

[0095] In summary, this invention dops europium into nickel metaphosphate. The synergistic effect of europium and nickel improves the catalytic activity and stability of the catalyst. Furthermore, the catalyst exhibits good morphology maintenance and high selectivity for the oxygen evolution reaction (OER), demonstrating promising market prospects.

Claims

1. A method for preparing an Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst, characterized in that, Using hydrophilic carbon cloth as a substrate, europium inorganic salt as the europium source, nickel inorganic salt as the nickel source, amino acids as rare earth anchoring agents, ammonium fluoride as a precipitant, and urea as a reducing agent, a carbon cloth-supported Eu-doped Ni(OH)₂ precursor was synthesized via hydrothermal reaction. Finally, a catalyst was prepared by a low-temperature phosphating process in an Ar / H₂ atmosphere. The process included the following steps: Step 1, Preparation of Eu-doped Ni(OH)₂ precursor Europium salt, nickel salt, urea, ammonium fluoride, and amino acids are mixed, wherein the molar ratio of europium salt, nickel salt, urea, and ammonium fluoride is 0.05~0.1:1.2~3:1~5:2~3, and the content of amino acids should exceed 2% of the molar content of the system. The mixture is dissolved in water, and pretreated hydrophilic carbon cloth is added. A hydrothermal reaction is carried out at a reaction temperature of 100~150℃ for 8~12 hours. After the reaction is completed, the mixture is washed and dried to obtain an Eu-doped Ni(OH)2 precursor, wherein the molar amount of nickel salt corresponding to each square centimeter of hydrophilic carbon cloth is 0.15~0.23 mmol. Step 2, Preparation of Eu-Ni(PO3)2 The Eu-doped Ni(OH)2 precursor from step 1 is placed in a quartz boat downstream of the Ar / H2 gas flow, and the phosphorus source is placed in a quartz boat upstream of the Ar / H2 gas flow. After the air in the tube furnace is exhausted, the temperature is raised to 250~450℃ and calcined for 30~150 minutes, with continuous gas flow during the calcination process, to obtain the carbon cloth-supported Eu-Ni(PO3)2 oxygen evolution electrocatalyst.

2. The method for preparing an Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst according to claim 1, characterized in that, The amino acid mentioned in step 1 is lysine or arginine.

3. The method for preparing an Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst according to claim 1, characterized in that, The pretreatment steps for the hydrophilic carbon cloth described in step 1 are as follows: After ultrasonic cleaning of the cut hydrophilic carbon cloth in ethanol, it is then rinsed clean with deionized water, followed by acidification treatment with dilute acid for 12 hours, and finally rinsed with deionized water until neutral. This removes oil and oxide layers from the surface of the hydrophilic carbon cloth.

4. The method for preparing an Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst according to claim 3, characterized in that, The dilute acid is a 1-3 mol / L nitric acid solution.

5. The method for preparing an Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst according to claim 1, characterized in that, The europium salt mentioned in step 1 is europium nitrate hexahydrate or europium chloride hexahydrate; the nickel salt is nickel nitrate hexahydrate, nickel chloride hexahydrate, or nickel sulfate hexahydrate.

6. The method for preparing an Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst according to claim 1, characterized in that, The phosphorus source mentioned in step 2 is sodium hypophosphite or potassium hypophosphite, and the ratio of the mass of phosphorus source required for calcination of a unit carbon cloth-loaded sample to the area of ​​the carbon cloth should not be less than 0.06 g·cm³. -2 .

7. The method for preparing an Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst according to claim 1, characterized in that, The heating rate during calcination in step 2 is 1~5℃ / min.

8. The application of Eu-doped Ni(PO3)2 porous nanosheet electrocatalyst prepared by any one of the preparation methods described in claims 1-7 as an anode catalyst in an anion exchange membrane water electrolysis device.

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