A method for preparing a perovskite-type La2NiO4 electrode material and its application in a photocatalytic urea fuel cell.

Abstract

This invention discloses a method for preparing perovskite-type La2NiO4 electrode material and its application in photocatalytic urea fuel cells, belonging to the field of perovskite-type La2NiO4 synthesis. The preparation method includes the following steps: S1: Lanthanum nitrate hexahydrate, nickel nitrate hexahydrate, and citric acid are dissolved in a mixture of deionized water and anhydrous ethanol. After stirring and dissolving, the solution is transferred to a reaction vessel, and graphite oxide is added. The mixture is then ultrasonically treated for 10-30 min; S2: The temperature is raised to 70-80℃ and kept at this temperature for a hydrothermal reaction for 2-8 h. Ammonium bicarbonate is then added, and the temperature is naturally lowered to 50℃ and kept at this temperature for stirring and reaction for 0.5-2 h. The mixture is then filtered; S3: The obtained La2NiO4 precursor is heat-treated in an air atmosphere; S4: The mixture is air-jet pulverized to 600 mesh and then mixed evenly with polyethylene glycol 6000. The mixture is then hot-pressed at 70℃. This invention uses the sol-gel template method to prepare a perovskite-type La2NiO4 photocatalyst, which is then applied to the membrane electrode material of urea fuel cells. This enables the photocatalytic oxidation of urea over a wide wavelength range with high catalytic efficiency.

Description

Technical Field

[0001] This invention belongs to the field of perovskite-type La2NiO4 synthesis and also relates to the field of urea fuel cells. Specifically, it relates to a method for preparing perovskite-type La2NiO4 electrode material and its application in photocatalytic urea fuel cells. Background Technology

[0002] With rapid industrialization and urbanization, urea, as one of the most common pollutants in wastewater, inevitably produces large amounts of ammonia and nitrates during its natural degradation, posing a serious threat to the environment and public health. Therefore, developing economical and efficient methods for urea removal from wastewater is of great significance. Meanwhile, urea, due to its high energy density (16.9 MJ L⁻¹), is widely considered an effective material for hydrogen transport and storage. Compared to water electrolysis (1.23 V vs. RHE), the electrolysis of urea solution exhibits a relatively low theoretical electrolysis voltage (0.37 V vs. RHE), which is advantageous for the electrolytic production of hydrogen from urea-containing wastewater. The largest source of urea is urine excreted by humans and livestock. High concentrations of urea in human urine have been widely used for hydrogen production and the direct construction of urine fuel cells.

[0003] Photoelectrocatalysis combines photocatalysis and electrocatalysis, maximizing the advantages of both technologies. It utilizes sunlight to generate photoelectrons, improving reaction activity and catalytic efficiency, while significantly reducing the need for external energy injection. Due to its high efficiency in utilizing solar energy, it is considered a promising technology for urea wastewater treatment and H2 production. In 2012, the first report on the photoelectrocatalytic oxidation of urea using Ni(OH)2-modified TiO2 as a photoelectrode sparked great interest in solar-driven urea and the release of hydrogen from human urine. Xie et al. further improved the photoelectrochemical oxidation activity of urea by using a Ni(OH)2-modified Ti-doped α-Fe2O3 photoanode. Currently, research reports on the urea oxidation reaction (UOR) using photocatalysts rarely fully utilize the entire solar spectrum (from UV to NIR), especially NIR light. Therefore, developing inexpensive transition metal-based photoelectrodes with broad spectral response is crucial for constructing urea fuel cells through photoelectrocatalysis, achieving efficient urea wastewater treatment, and clean energy conversion.

[0004] The efficiency of urea oxidation depends on the rate of the anodic urea oxidation reaction; however, UOR (Ultra-Organic Oxidation) is a slow kinetic process involving six electron transfers. Therefore, using high-performance photocatalysts to reduce the UOR overpotential is key to accelerating the kinetics. Nickel-based catalysts have been widely developed for urea electrolysis because they can effectively reduce the UOR activity potential. Among nickel-based catalysts, perovskite oxides are the most attractive due to their flexible composition and excellent light absorption capabilities. Perovskite oxides are typically prepared under high-temperature conditions, and high-temperature thermal decomposition results in fewer surface active sites and lower activity. Therefore, improving the surface active sites of nickel-based perovskite oxides is crucial for enhancing the performance of solar-driven urea oxidation and achieving urea wastewater treatment and energy conversion. In summary, developing corresponding two-dimensional porous La2NiO4 shows great potential for photocatalytic applications in urea fuel cells and for practical all-weather urea wastewater treatment. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing perovskite-type La2NiO4 electrode material and its application in photocatalytic urea fuel cells.

[0006] The technical solution of this invention is summarized as follows:

[0007] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0008] S1: After mixing deionized water and anhydrous ethanol evenly, add lanthanum nitrate hexahydrate, nickel nitrate hexahydrate, and citric acid. Stir to dissolve, then transfer to a reaction vessel, add graphite oxide, and sonicate for 10-30 minutes.

[0009] S2: After closing the valve of the reactor, heat it to 70-80℃ and keep it at that temperature for 2-8 hours for hydrothermal reaction. Then open the valve, add ammonium bicarbonate, let it cool down naturally to 50℃ and keep it at that temperature for 0.5-2 hours for stirring reaction. After filtration, the La2NiO4 precursor is obtained.

[0010] S3: In an air atmosphere, the La2NiO4 precursor is heat-treated to obtain perovskite-type La2NiO4 powder material.

[0011] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling method, and then the obtained perovskite-type La2NiO4 powder is mixed evenly with polyethylene glycol 6000 and hot-pressed at 70℃ to obtain perovskite-type La2NiO4 film electrode material.

[0012] Furthermore, the reactor is made of stainless steel.

[0013] Furthermore, the ultrasonic power of the ultrasonic treatment is 3kW.

[0014] Furthermore, the specific process of the heat treatment is as follows: the La2NiO4 precursor is heated to 400°C at a certain heating rate and held at that temperature for 2-4 hours, and then heated to 800°C at a certain heating rate and held at that temperature for 1-2 hours.

[0015] Furthermore, the specified heating rate is 1-10℃ / min.

[0016] Further, in S1-S3, the ratio of deionized water, anhydrous ethanol, lanthanum nitrate hexahydrate, nickel nitrate hexahydrate, citric acid, graphite oxide, and ammonium bicarbonate is (2-4) mL:(1-2) mL:(0.5-0.7) mmol:(0.5-0.7) mmol:(0.63-0.72) g:(0.1-0.15) g:(0.5-0.8) g.

[0017] Furthermore, the molar ratio of lanthanum nitrate hexahydrate to nickel nitrate hexahydrate is 1:1.

[0018] Furthermore, in S4, the molar ratio of the perovskite-type La2NiO4 powder to polyethylene glycol 6000 is 100:1.

[0019] The present invention also provides the application of the perovskite-type La2NiO4 electrode material prepared by the above preparation method in photocatalytic urea fuel cells.

[0020] Furthermore, a perovskite-type La2NiO4 membrane electrode material was bonded and pressed with an AMI-7001 type anion exchange membrane to form a cathode membrane electrode. A carbon membrane electrode was used as the working electrode, a Pt electrode as the auxiliary electrode, and an Hg / HgO electrode as the reference electrode. The electrode was installed in an H-type membrane electrolyzer with 1M KOH and 0.5M urea as electrolytes. A constant potential of 0.55V was applied to the working electrode, and a 300W xenon lamp was used for radiation as a full-spectrum light source with a wavelength of 200nm≤λ≤1100nm to carry out the photoelectrocatalytic oxidation reaction of urea.

[0021] The beneficial effects of this invention are:

[0022] This invention uses citric acid as a template agent to prepare a perovskite-type La2NiO4 photocatalyst using the sol-gel template method. When applied to the membrane electrode material of urea fuel cells, it can achieve photocatalytic oxidation of urea over a wide wavelength range with high catalytic efficiency, making it suitable for large-scale production. This provides a new approach for hydrogen production technology and the direct construction of urea fuel cells. Attached Figure Description

[0023] Figure 1This is a flowchart of the preparation method of the perovskite-type La2NiO4 electrode material of the present invention;

[0024] Figure 2 SEM image of the perovskite-type La2NiO4 powder material prepared in Example 1;

[0025] Figure 3 SEM image of the perovskite-type La2NiO4 powder material prepared in Example 10;

[0026] Figure 4 SEM image of the perovskite-type La2NiO4 film electrode material prepared in Example 1;

[0027] Figure 5 SEM image of the perovskite-type La2NiO4 film electrode material prepared in Example 3;

[0028] Figure 6 SEM image of the perovskite-type La2NiO4 film electrode material prepared in Example 6;

[0029] Figure 7 The XRD pattern of the perovskite-type La2NiO4 powder material prepared by this invention;

[0030] Figure 8 The absorption spectrum of the perovskite-type La2NiO4 powder material prepared by this invention is shown below.

[0031] Figure 9 A schematic diagram illustrating the working principle of a photocatalytic urea fuel cell using perovskite-type La2NiO4 electrode material;

[0032] Figure 10 The UOR curves of the urea fuel cell constructed using the La2NiO4 electrode material of Example 1 under different light conditions are shown.

[0033] Figure 11 The HER curves of the urea fuel cell constructed using the La2NiO4 electrode material of Example 1 under different light conditions are shown.

[0034] Figure 12 The graph shows the photocurrent variation of the urea fuel cell constructed using the La2NiO4 electrode material of Example 1 under different light conditions.

[0035] Figure 13 The graph shows the hydrogen evolution curves of the urea fuel cell constructed using the La2NiO4 electrode material of Example 1 under different light conditions. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0037] This invention provides a method for preparing a perovskite-type La2NiO4 electrode material, comprising the following steps:

[0038] S1: After mixing deionized water and anhydrous ethanol evenly, add lanthanum nitrate hexahydrate, nickel nitrate hexahydrate, and citric acid. After stirring and dissolving, transfer to a stainless steel reactor, add graphite oxide, and use an ultrasonic wave with a power of 3kW to sonicate for 10-30 minutes.

[0039] S2: After closing the valve of the stainless steel reactor, heat it to 70-80℃ and keep it at that temperature for 2-8 hours for hydrothermal reaction. Then open the valve, add ammonium bicarbonate, and let it cool down naturally to 50℃ and keep it at that temperature for 0.5-2 hours with stirring. After filtration, the La2NiO4 precursor is obtained.

[0040] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 1-10℃ / min and held for 2-4 hours. Then, it is heated to 800℃ at a heating rate of 1-10℃ / min and held for 1-2 hours to obtain perovskite-type La2NiO4 powder material.

[0041] In S1-S3, the ratio of deionized water, anhydrous ethanol, lanthanum nitrate hexahydrate, nickel nitrate hexahydrate, citric acid, graphite oxide, and ammonium bicarbonate is (2-4) mL:(1-2) mL:(0.5-0.7) mmol:(0.5-0.7) mmol:(0.63-0.72) g:(0.1-0.15) g:(0.5-0.8) g; furthermore, the molar ratio of lanthanum nitrate hexahydrate and nickel nitrate hexahydrate is 1:1.

[0042] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0043] The application of the perovskite-type La2NiO4 electrode material prepared by the method in this embodiment in a photocatalytic urea fuel cell: The perovskite-type La2NiO4 membrane electrode material is bonded and pressed with an AMI-7001 type anion exchange membrane to form a cathode membrane electrode. A carbon membrane electrode is used as the working electrode, a Pt electrode as the auxiliary electrode, and an Hg / HgO electrode as the reference electrode. The electrode is installed in an H-type membrane electrolyzer with 1M KOH and 0.5M urea as electrolytes. A constant potential of 0.55V is applied to the working electrode, and a 300W xenon lamp is used for radiation as a full-spectrum light source (AM 1.5G, 300nm<λ<1100nm simulated sunlight, λ<420nm or λ<780nm visible light, λ>800nm ​​near-infrared light source) for the photoelectrocatalytic oxidation reaction of urea.

[0044] Example 1

[0045] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0046] S1: Mix 2L of deionized water and 1L of anhydrous ethanol evenly, then add 216.5g of lanthanum nitrate hexahydrate, 145.4g of nickel nitrate hexahydrate, and 630g of citric acid. After stirring and dissolving, transfer the mixture to a 10L stainless steel reactor, add 50g of graphite oxide, and sonicate for 15 minutes using an ultrasonic wave with a power of 3kW.

[0047] S2: After closing the valve of the stainless steel reactor, heat it to 70℃ and keep it at that temperature for 6 hours for hydrothermal reaction. Then open the valve, add 500g of ammonium bicarbonate, and let it cool down naturally to 50℃ and keep it at that temperature for 0.5 hours with stirring. After filtration, the La2NiO4 precursor is obtained.

[0048] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 4℃ / min and held for 2 hours. Then, it is heated to 800℃ at a heating rate of 4℃ / min and held for 1 hour to obtain perovskite-type La2NiO4 powder material.

[0049] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0050] Example 2

[0051] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0052] S1: Mix 2L of deionized water and 2L of anhydrous ethanol evenly, then add 259.8g of lanthanum nitrate hexahydrate, 174.5g of nickel nitrate hexahydrate, and 630g of citric acid. After stirring and dissolving, transfer the mixture to a 10L stainless steel reactor, add 150g of graphite oxide, and sonicate for 15 minutes using an ultrasonic wave with a power of 3kW.

[0053] S2: After closing the valve of the stainless steel reactor, heat it to 70℃ and keep it at that temperature for 4 hours for hydrothermal reaction. Then open the valve, add 500g of ammonium bicarbonate, and let it cool down naturally to 50℃ and keep it at that temperature for 1 hour for stirring. After filtration, the La2NiO4 precursor is obtained.

[0054] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 4℃ / min and held for 4h. Then, it is heated to 800℃ at a heating rate of 4℃ / min and held for 1h to obtain perovskite-type La2NiO4 powder material.

[0055] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0056] Example 3

[0057] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0058] S1: Mix 1L of deionized water and 2L of anhydrous ethanol evenly, then add 303.1g of lanthanum nitrate hexahydrate, 203.6g of nickel nitrate hexahydrate and 630g of citric acid. After stirring and dissolving, transfer to a 10L stainless steel reactor, add 150g of graphite oxide, and sonicate for 30 minutes using an ultrasonic wave with a power of 3kW.

[0059] S2: After closing the valve of the stainless steel reactor, heat it to 80℃ and keep it at that temperature for 2 hours for hydrothermal reaction. Then open the valve, add 500g of ammonium bicarbonate, let it cool down naturally to 50℃ and keep it at that temperature for 0.5 hours for stirring. After filtration, the La2NiO4 precursor is obtained.

[0060] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 4℃ / min and held for 2 hours. Then, it is heated to 800℃ at a heating rate of 1-10℃ / min and held for 1 hour to obtain perovskite-type La2NiO4 powder material.

[0061] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0062] Example 4

[0063] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0064] S1: Mix 4L of deionized water and 1L of anhydrous ethanol evenly, then add 216.5g of lanthanum nitrate hexahydrate, 145.4g of nickel nitrate hexahydrate, and 630g of citric acid. After stirring and dissolving, transfer the mixture to a 10L stainless steel reactor, add 150g of graphite oxide, and sonicate for 30 minutes using an ultrasonic wave with a power of 3kW.

[0065] S2: After closing the valve of the stainless steel reactor, heat it to 70℃ and keep it at that temperature for 4 hours for hydrothermal reaction. Then open the valve, add 800g of ammonium bicarbonate, and let it cool down naturally to 50℃ and keep it at that temperature for 2 hours for stirring. After filtration, the La2NiO4 precursor is obtained.

[0066] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 4℃ / min and held for 2 hours. Then, it is heated to 800℃ at a heating rate of 4℃ / min and held for 1 hour to obtain perovskite-type La2NiO4 powder material.

[0067] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0068] Example 5

[0069] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0070] S1: Mix 2L of deionized water and 2L of anhydrous ethanol evenly, then add 216.5g of lanthanum nitrate hexahydrate, 145.4g of nickel nitrate hexahydrate and 720g of citric acid. After stirring and dissolving, transfer to a 10L stainless steel reactor, add 150g of graphite oxide, and sonicate for 20 minutes using an ultrasonic wave with a power of 3kW.

[0071] S2: After closing the valve of the stainless steel reactor, heat it to 80℃ and keep it at that temperature for 2 hours for hydrothermal reaction. Then open the valve, add 800g of ammonium bicarbonate, and let it cool down naturally to 50℃ and keep it at that temperature for 1.5 hours for stirring. After filtration, the La2NiO4 precursor is obtained.

[0072] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 4℃ / min and held for 2 hours. Then, it is heated to 800℃ at a heating rate of 4℃ / min and held for 1 hour to obtain perovskite-type La2NiO4 powder material.

[0073] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0074] Example 6

[0075] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0076] S1: Mix 3L of deionized water and 2L of anhydrous ethanol evenly, then add 216.5g of lanthanum nitrate hexahydrate, 145.4g of nickel nitrate hexahydrate and 720g of citric acid. After stirring and dissolving, transfer to a 10L stainless steel reactor, add 150g of graphite oxide, and sonicate for 10 minutes using an ultrasonic wave with a power of 3kW.

[0077] S2: After closing the valve of the stainless steel reactor, heat it to 80℃ and keep it at that temperature for 5 hours for hydrothermal reaction. Then open the valve, add 800g of ammonium bicarbonate, cool it down to 50℃ naturally and keep it at that temperature for 1 hour with stirring. After filtration, the La2NiO4 precursor is obtained.

[0078] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 5℃ / min and held for 4h. Then, it is heated to 800℃ at a heating rate of 5℃ / min and held for 2h to obtain perovskite-type La2NiO4 powder material.

[0079] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0080] Example 7

[0081] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0082] S1: Mix 4L of deionized water and 1L of anhydrous ethanol evenly, then add 216.5g of lanthanum nitrate hexahydrate, 145.4g of nickel nitrate hexahydrate and 720g of citric acid. After stirring and dissolving, transfer to a 10L stainless steel reactor, add 150g of graphite oxide, and sonicate for 15min using an ultrasonic wave with a power of 3kW.

[0083] S2: After closing the valve of the stainless steel reactor, heat it to 80℃ and keep it at that temperature for 8 hours for hydrothermal reaction. Then open the valve, add 800g of ammonium bicarbonate, and let it cool down to 50℃ naturally and keep it at that temperature for 2 hours with stirring. After filtration, the La2NiO4 precursor is obtained.

[0084] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 10℃ / min and held for 4 hours. Then, it is heated to 800℃ at a heating rate of 10℃ / min and held for 2 hours to obtain perovskite-type La2NiO4 powder material.

[0085] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0086] Example 8

[0087] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0088] S1: Mix 2L of deionized water and 1L of anhydrous ethanol evenly, then add 216.5g of lanthanum nitrate hexahydrate, 145.4g of nickel nitrate hexahydrate and 720g of citric acid. After stirring and dissolving, transfer to a 10L stainless steel reactor, add 150g of graphite oxide, and sonicate for 15min using an ultrasonic wave with a power of 3kW.

[0089] S2: After closing the valve of the stainless steel reactor, heat it to 80℃ and keep it at that temperature for 8 hours for hydrothermal reaction. Then open the valve, add 800g of ammonium bicarbonate, and let it cool down to 50℃ naturally and keep it at that temperature for 2 hours with stirring. After filtration, the La2NiO4 precursor is obtained.

[0090] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 2℃ / min and held for 2h. Then, it is heated to 800℃ at a heating rate of 2℃ / min and held for 1h to obtain perovskite-type La2NiO4 powder material.

[0091] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0092] Example 9

[0093] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0094] S1: Mix 2L of deionized water and 1L of anhydrous ethanol evenly, then add 216.5g of lanthanum nitrate hexahydrate, 145.4g of nickel nitrate hexahydrate and 720g of citric acid. After stirring and dissolving, transfer to a 10L stainless steel reactor, add 150g of graphite oxide, and sonicate for 10 minutes using an ultrasonic wave with a power of 3kW.

[0095] S2: After closing the valve of the stainless steel reactor, heat it to 80℃ and keep it at that temperature for 6 hours for hydrothermal reaction. Then open the valve, add 800g of ammonium bicarbonate, and let it cool down naturally to 50℃ and keep it at that temperature for 1.5 hours for stirring. After filtration, the La2NiO4 precursor is obtained.

[0096] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 2℃ / min and held for 2h. Then, it is heated to 800℃ at a heating rate of 2℃ / min and held for 1h to obtain perovskite-type La2NiO4 powder material.

[0097] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0098] Example 10

[0099] A method for preparing a perovskite-type La2NiO4 electrode material includes the following steps:

[0100] S1: Mix 2L of deionized water and 1L of anhydrous ethanol evenly, then add 216.5g of lanthanum nitrate hexahydrate, 145.4g of nickel nitrate hexahydrate and 720g of citric acid. After stirring and dissolving, transfer to a 10L stainless steel reactor, add 150g of graphite oxide, and sonicate for 15min using an ultrasonic wave with a power of 3kW.

[0101] S2: After closing the valve of the stainless steel reactor, heat it to 80℃ and keep it at that temperature for 4 hours for hydrothermal reaction. Then open the valve, add 800g of ammonium bicarbonate, cool it down naturally to 50℃ and keep it at that temperature for 1 hour for stirring reaction. After filtration, the La2NiO4 precursor is obtained.

[0102] S3: In an air atmosphere, the La2NiO4 precursor is heated to 400℃ at a heating rate of 1℃ / min and held for 2 hours. Then, it is heated to 800℃ at a heating rate of 1℃ / min and held for 1 hour to obtain perovskite-type La2NiO4 powder material.

[0103] S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling. Then, the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 at a molar ratio of 100:1 and hot-pressed at 70°C to obtain perovskite-type La2NiO4 film electrode material.

[0104] Application of perovskite-type La2NiO4 electrode material prepared by the method in Examples 1-10 in photocatalytic urea fuel cells: The perovskite-type La2NiO4 membrane electrode material is bonded and pressed with an AMI-7001 type anion exchange membrane to form a cathode membrane electrode. A carbon membrane electrode is used as the working electrode, a Pt electrode as the auxiliary electrode, and an Hg / HgO electrode as the reference electrode. The electrode is installed in an H-type membrane electrolyzer with 1M KOH and 0.5M urea as electrolytes. A constant potential of 0.55V is applied to the working electrode, and a 300W xenon lamp is used for radiation as a full-spectrum light source (AM 1.5G, 300nm<λ<1100nm UV-vis-NIR simulated sunlight, λ<420nm or λ<780nmvis visible light, λ>800nm ​​NIR near-infrared light source) for the photoelectrocatalytic oxidation reaction of urea.

[0105] The UOR and HER of the perovskite-type La2NiO4 electrode material prepared in Example 1 were tested under ultraviolet-visible (NIR) light, visible light, near-infrared light, and darkness for 8 hours, and the changes in photocurrent within 8 hours were recorded. The UOR curves of the La2NiO4 electrode material under different illumination conditions are shown in the figure below. Figure 10 As shown in the figure, the HER curve is as follows: Figure 11 As shown, the photocurrent variation curve is as follows: Figure 12 As shown; gas samples were taken using a 0.5 mL pipette, and the hydrogen generation rate was analyzed using a gas chromatograph (GC9800(N), Shanghai Kechuang Chromatography Co., Ltd., China, TCD, nitrogen as carrier gas, 5a molecular sieve column). The hydrogen evolution curves under different light conditions are shown in the figure. Figure 13 As shown.

[0106] according to Figure 10-13 It is known that under ultraviolet-visible (NIR) light conditions, the urea fuel cell constructed using perovskite-type La2NiO4 electrode material outperforms other light conditions in terms of electrochemical performance and hydrogen generation rate. This indicates that the urea fuel cell constructed using perovskite-type La2NiO4 electrode material in this invention can absorb and utilize the full spectrum of light sources, thereby exhibiting superior photoelectrocatalytic performance.

[0107] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A method for preparing a perovskite-type La2NiO4 electrode material, characterized in that, Includes the following steps: S1: After mixing deionized water and anhydrous ethanol evenly, add lanthanum nitrate hexahydrate, nickel nitrate hexahydrate, and citric acid. Stir to dissolve, then transfer to a reaction vessel, add graphite oxide, and sonicate for 10-30 minutes. S2: After closing the valve of the reactor, heat it to 70-80℃ and keep it at that temperature for 2-8 hours for hydrothermal reaction. Then open the valve, add ammonium bicarbonate, let it cool down naturally to 50℃ and keep it at that temperature for 0.5-2 hours for stirring reaction. After filtration, the La2NiO4 precursor is obtained. S3: In an air atmosphere, the La2NiO4 precursor is heat-treated to obtain perovskite-type La2NiO4 powder material. S4: The obtained perovskite-type La2NiO4 powder material is pulverized to 600 mesh using air jet milling method, and then the obtained perovskite-type La2NiO4 powder is mixed with polyethylene glycol 6000 evenly and hot-pressed at 70℃ to obtain perovskite-type La2NiO4 film electrode material. In S1-S3, the ratio of deionized water, anhydrous ethanol, lanthanum nitrate hexahydrate, nickel nitrate hexahydrate, citric acid, graphite oxide, and ammonium bicarbonate is (2-4) mL:(1-2) mL:(0.5-0.7) mmol:(0.5-0.7) mmol:(0.63-0.72) g:(0.1-0.15) g:(0.5-0.8) g; In S4, the molar ratio of the perovskite-type La2NiO4 powder to polyethylene glycol 6000 is 100:

1.

2. The method for preparing a perovskite-type La2NiO4 electrode material according to claim 1, characterized in that, The reactor is made of stainless steel.

3. The method for preparing a perovskite-type La2NiO4 electrode material according to claim 1, characterized in that, The ultrasonic power of the ultrasonic treatment is 3kW.

4. The method for preparing a perovskite-type La2NiO4 electrode material according to claim 1, characterized in that, The specific process of the heat treatment is as follows: the La2NiO4 precursor is heated to 400℃ at a certain heating rate and held at that temperature for 2-4 hours, and then heated to 800℃ at a certain heating rate and held at that temperature for 1-2 hours.

5. The method for preparing a perovskite-type La2NiO4 electrode material according to claim 4, characterized in that, The specified heating rate is 1-10℃ / min.

6. The method for preparing a perovskite-type La2NiO4 electrode material according to claim 1, characterized in that, The molar ratio of lanthanum nitrate hexahydrate to nickel nitrate hexahydrate is 1:

1.

7. The application of a perovskite-type La2NiO4 electrode material prepared by the preparation method according to any one of claims 1-6 in a photocatalytic urea fuel cell.

8. The application according to claim 7, characterized in that: A perovskite-type La2NiO4 membrane electrode material was bonded and pressed with an AMI-7001 type anion exchange membrane to form a cathode membrane electrode. A carbon membrane electrode was used as the working electrode, a Pt electrode as the auxiliary electrode, and an Hg / HgO electrode as the reference electrode. The electrode was installed in an H-type membrane electrolyzer with 1M KOH and 0.5M urea as electrolytes. A constant potential of 0.55V was applied to the working electrode, and a 300W xenon lamp was used for radiation as a full-spectrum light source with a wavelength of 200nm≤λ≤1100nm to carry out the photoelectrocatalytic oxidation reaction of urea.

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