Cobalt-doped lanthanum nickelate perovskite oxide single crystal thin film composite electrode and preparation method

Abstract

This invention belongs to the field of composite electrode fabrication technology, and discloses a cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin film composite electrode, its fabrication method, and its application. LaNi is deposited and grown on a LaAlO3(001) substrate using laser pulse deposition technology. 0.7 Co 0.3 The O3 thin film produces electrode materials with high adhesion, strong repeatability, and high flatness. The LaNi... (The sentence is incomplete and requires further context to translate accurately.) 0.7 Co 0.3 The O3 thin-film composite electrode, when applied to an electrocatalytic water electrolysis oxygen evolution reaction system, can effectively catalyze and promote the oxygen evolution reaction. This invention demonstrates that cobalt-doped lanthanum nickelate engineering can effectively regulate the crystal structure and thus adjust the electronic structure, representing an effective strategy for enhancing the electrocatalytic performance of perovskites. It also provides possibilities for designing and improving perovskite oxide electrocatalysts with better catalytic performance.

Description

Technical Field

[0001] This invention belongs to the field of composite electrode preparation technology, and particularly relates to a cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin film composite electrode, its preparation method and application. Background Technology

[0002] The rapid increase in global energy demand due to modernization has led to the excessive consumption of non-renewable fossil fuels, severely impacting the environment and energy supply. To address the energy crisis and environmental degradation, a shift in energy strategy has been pursued, prompting research and development of new "green" energy technologies. Electrochemical water splitting to produce pollution-free hydrogen fuel and oxygen is considered an effective means of storing intermittent renewable energy. However, the oxygen evolution reaction (OER) itself has sluggish reaction kinetics, requiring a large overpotential to drive the basic chemical reaction. Therefore, preparing highly active OER electrocatalysts to significantly reduce the overpotential and improve efficiency is essential. Although noble metal materials such as IrO2 and RuO2 exhibit high OER catalytic activity, their scarcity and high cost limit large-scale industrial production and commercial application. In recent years, research has revealed that perovskite oxides (with the molecular formula ABO3) hold promise as novel OER catalysts due to their wide elemental distribution, diverse structures, low cost, and high activity and stability in alkaline solutions.

[0003] While extensive research has been conducted on the catalytic performance of lanthanum nickelate perovskite oxide films in the field of OER (Optical Eruption Reactor) catalysis, research on the catalytic properties of single-crystal cobalt-doped lanthanum nickelate film composite electrodes is still relatively scarce. Cobalt-doped lanthanum nickelate films exhibit better catalytic activity and stability in alkaline solutions, effectively promoting the OER reaction.

[0004] Based on the above analysis, the problems and shortcomings of the existing technology are as follows:

[0005] (1) The oxygen evolution reaction (OER) process itself has slow reaction kinetics and requires a large overpotential to drive the basic chemical reaction. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode, its preparation method, and its application.

[0007] This invention is achieved as follows: a method for preparing a cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode includes:

[0008] Step 1: Preparation of LaNi 0.7 Co 0.3 O3 target material;

[0009] Lanthanum oxide, nickel oxide, and cobalt tetroxide were mixed according to LaNi 0.7 Co 0.3 After weighing and grinding the O3 molecules according to their stoichiometric molar ratio, they were sintered to produce LaNi. 0.7 Co 0.3 O3 target material;

[0010] Step 2, substrate pretreatment;

[0011] The LaAlO3(001) substrate was ultrasonically cleaned and then dried with inert gas before use.

[0012] Step 3, Preparation of LaNi 0.7 Co 0.3 O3 thin film;

[0013] The obtained LaNi 0.7 Co 0.3 An O3 target and a LaAlO3(001) substrate were placed in a pulsed laser deposition system. After evacuation, LaNi was deposited under constant oxygen partial pressure and laser energy density. 0.7 Co 0.3 O3 target pre-sputtering is performed, followed by LaNi target pre-sputtering. 0.7 Co 0.3 The O3 target material was laser-ablated and deposited onto a conductive substrate. The LaNi was then removed under a nitrogen atmosphere. 0.7 Co 0.3 O3 thin film;

[0014] Step four: Prepare the composite electrode;

[0015] The obtained LaNi 0.7 Co 0.3 The O3 thin film was fixed onto a glass slide using silver paste, and an ohmic contact was formed by connecting one end of the film with copper paste. Hot melt adhesive was applied around the film to prevent the substrate, silver, and copper from being directly exposed to the electrolyte and affecting electrochemical testing. This process yielded LaNi. 0.7 Co 0.3 O3 thin film composite electrode.

[0016] Furthermore, in step one, two sintering processes are carried out. The first pre-calcination temperature is 800-1000℃ and the sintering time is 11-13h. The second sintering temperature is 1100-1300℃ and the time is 11-13h.

[0017] Furthermore, the ultrasonic cleaning process in step two includes the following steps: ultrasonic cleaning with acetone, anhydrous ethanol and deionized water for 10-20 minutes each in sequence.

[0018] Furthermore, in step three, the pressure inside the deposition system after evacuation is 5.0 × 10⁻⁶. -4-5.2×10 -4 Pa.

[0019] Furthermore, in step three, the pre-sputtering time is 5-10 minutes, and the laser ablation time is 28-32 minutes; the substrate and LaNi 0.7 Co 0.3 The distance between O3 targets is 50-60 mm, the growth temperature is maintained at 700℃, the oxygen pressure is 1-30 Pa, and the laser sputtering energy density is 2.0 J / cm³. -2 The laser frequency is 8Hz.

[0020] Furthermore, in step three, the film is removed under a nitrogen atmosphere with a nitrogen pressure of 1×10⁻⁶. 5 Pa.

[0021] A cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode prepared according to the method described above.

[0022] Furthermore, the system includes a working electrode, an auxiliary electrode, a reference electrode, and an electrolyte, wherein the working electrode includes the LaNi0 electrode. 0.7 Co 0.3 O3 thin film composite electrode.

[0023] Furthermore, the auxiliary electrode is a platinum wire electrode, the reference electrode is an Hg / HgO electrode, and the electrolyte is a 0.1-1 mol / L potassium hydroxide aqueous solution.

[0024] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0025] First, addressing the technical problems existing in the prior art and the difficulty in solving them, this paper closely analyzes, in conjunction with the technical solution to be protected by this invention and the results and data obtained during the research and development process, how the technical solution of this invention solves the technical problems, and the inventive technical effects brought about by solving these problems. The specific description is as follows:

[0026] The preparation method provided by this invention uses abundant raw materials, such as LaNi. 0.7 Co 0.3 O3 targets are reusable, easy and quick to operate, highly safe, and conducive to large-scale production. The relationship between the substrate and LaNi can be adjusted. 0.7 Co 0.3 The film thickness is precisely controlled by adjusting the distance between O3 targets and the laser sputtering time, resulting in controllable film thickness, stable performance, and high repeatability.

[0027] LaNi prepared by this invention 0.7 Co 0.3The O3 thin film composite electrode can be directly used as a reaction electrode. It has good conductivity, good stability in the oxygen evolution reaction of water electrolysis, and high electrocatalytic activity.

[0028] LaNi 0.7 Co 0.3 Compared to undoped LaNiO3 single crystal films, O3 thin films alter the chemical composition of the material and regulate the electronic structure by adjusting the crystal structure, thereby enhancing the orbital hybridization of Ni / Co 3d-O 2p. Therefore, during chemical reactions, they can provide more active sites for electrochemical reactions.

[0029] LaNi provided by the present invention 0.7 Co 0.3 The O3 thin-film composite electrode, when applied to an electrocatalytic water electrolysis oxygen evolution reaction system, can effectively catalyze and promote the oxygen evolution reaction.

[0030] This invention utilizes laser pulses to deposit and grow LaNi on a LaAlO3(001) substrate. 0.7 Co 0.3 O3 produces electrode materials with high bonding strength, strong repeatability, and high flatness.

[0031] This invention demonstrates that cobalt-doped lanthanum nickelate engineering can effectively regulate the crystal structure and thus adjust the electronic structure, which is an effective means to enhance the electrocatalytic performance of perovskites and can become an effective and universal strategy for designing next-generation high-performance catalysts for the oxygen evolution reaction in water electrolysis.

[0032] Second, considering the technical solution as a whole or from a product perspective, the technical effects and advantages of the technical solution to be protected by this invention are specifically described as follows:

[0033] The preparation method provided by this invention uses abundant raw materials, such as LaNi. 0.7 Co 0.3 O3 targets are reusable, easy and quick to operate, highly safe, and conducive to large-scale production. The relationship between the substrate and LaNi can be adjusted. 0.7 Co 0.3 The film thickness is precisely controlled by adjusting the distance between O3 targets and the laser sputtering time, resulting in controllable film thickness, stable performance, and high repeatability.

[0034] LaNi prepared by this invention 0.7 Co 0.3 The O3 thin film composite electrode can be directly used as a reaction electrode. It has good conductivity, good stability in the oxygen evolution reaction of water electrolysis, and high electrocatalytic activity.

[0035] LaNi 0.7 Co 0.3Compared to undoped LaNiO3 single crystal films, O3 thin films alter the chemical composition of the material and regulate the electronic structure by adjusting the crystal structure, thereby enhancing the orbital hybridization of Ni / Co 3d-O 2p. Therefore, during chemical reactions, they can provide more active sites for electrochemical reactions.

[0036] LaNi provided by the present invention 0.7 Co 0.3 The O3 thin-film composite electrode, when applied to an electrocatalytic water electrolysis oxygen evolution reaction system, can effectively catalyze and promote the oxygen evolution reaction.

[0037] This invention utilizes laser pulses to deposit and grow LaNi on a LaAlO3(001) substrate. 0.7 Co 0.3 O3 produces electrode materials with high bonding strength, strong repeatability, and high flatness.

[0038] This invention demonstrates that cobalt-doped lanthanum nickelate engineering can effectively regulate the crystal structure and thus adjust the electronic structure, which is an effective means to enhance the electrocatalytic performance of perovskites and can become an effective and universal strategy for designing next-generation high-performance catalysts for the oxygen evolution reaction in water electrolysis.

[0039] Third, as supplementary evidence of the inventive step of the claims of this invention, it is also reflected in the following important aspects:

[0040] Does the technical solution of this invention solve a technical problem that people have long desired to solve but have never been able to successfully address?

[0041] Lanthanum nickelate, as the only rare-earth nickelate with a high metallicity perovskite structure, possesses unique intrinsic activity for OER reactions. However, as an electrocatalyst, its inherent low activity still limits its performance, requiring a large overpotential to drive the basic chemical reaction. Introducing cobalt ions into lanthanum nickelate introduces crystal structure distortion, which not only enhances the 3d-O2p orbital hybridization of Ni / Co, improving its intrinsic activity, but also effectively reduces the LaNi... 0.7 Co 0.3 The barrier of O3 materials for OER reaction. Compared with the large volume of nanostructures and bulk perovskite oxides synthesized by the typical sol-gel method, which leads to a very low surface area, thin film materials prepared by PLD technology can be used as 2D planar materials. The film growth conditions can be precisely controlled to control the adsorption of reactants by the crystal structure, making them ideal materials for designing OER electrocatalysts. Attached Figure Description

[0042] Figure 1 This is a flowchart of the method for preparing a cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin film composite electrode according to an embodiment of the present invention.

[0043] Figure 2 The LaNi provided in the embodiments of the present invention 0.7 Co 0.3 Linear voltammetric curves of the catalytic activity of the O3 thin-film composite electrode in the OER reaction.

[0044] Figure 3 The LaNi provided in the embodiments of the present invention 0.7 Co 0.3 Cyclic voltammetry curves of the double-layer capacitance of the O3 thin-film composite electrode.

[0045] Figure 4 The LaNi provided in the embodiments of the present invention 0.7 Co 0.3 Schematic diagram of the double-layer capacitance of the O3 thin-film composite electrode.

[0046] Figure 5 The LaNi provided in the embodiments of the present invention 0.7 Co 0.3 Electrochemical impedance spectroscopy of O3 thin film composite electrode.

[0047] Figure 6 The LaNi within 3000s provided in the embodiments of the present invention 0.7 Co 0.3 The graph shows the variation of current density in the O3 thin film composite electrode. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0049] To enable those skilled in the art to fully understand how the present invention is specifically implemented, this section provides an explanatory description of the embodiments that expand upon the technical solutions of the claims.

[0050] like Figure 1 As shown, the present invention provides a method for preparing a cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode, comprising the following steps:

[0051] S101, Preparation of LaNi 0.7 Co 0.3 O3 target material;

[0052] Lanthanum oxide, nickel oxide, and cobalt tetroxide were mixed according to LaNi 0.7 Co 0.3 After weighing and grinding the O3 molecules according to their stoichiometric molar ratio, they were sintered to produce LaNi. 0.7 Co 0.3 O3 target material;

[0053] S102, Substrate pretreatment;

[0054] The LaAlO3(001) substrate was ultrasonically cleaned and then dried with inert gas before use.

[0055] S103, Preparation of LaNi 0.7 Co 0.3 O3 thin film;

[0056] The obtained LaNi 0.7 Co 0.3 An O3 target and a LaAlO3(001) substrate were placed in a pulsed laser deposition system. After evacuation, LaNi was deposited under constant oxygen partial pressure and laser energy density. 0.7 Co 0.3 O3 target pre-sputtering is performed, followed by LaNi target pre-sputtering. 0.7 Co 0.3 The O3 target material was laser-ablated and deposited onto a conductive substrate. The LaNi was then removed under a nitrogen atmosphere. 0.7 Co 0.3 O3 thin film;

[0057] S104, used to prepare composite electrodes;

[0058] The obtained LaNi 0.7 Co 0.3 The O3 thin film was fixed onto a glass slide using silver paste, and an ohmic contact was formed by connecting one end of the film with copper paste. Hot melt adhesive was applied around the film to prevent the substrate, silver, and copper from being directly exposed to the electrolyte and affecting electrochemical testing. This process yielded LaNi. 0.7 Co 0.3 O3 thin film composite electrode.

[0059] The S101 provided by this invention undergoes two sintering processes. The first pre-calcination temperature is 800-1000℃ and the sintering time is 11-13h. The second sintering temperature of S102 is 1100-1300℃ and the time is 11-13h.

[0060] The ultrasonic cleaning process in S102 provided by the present invention includes the following steps: ultrasonic cleaning with acetone, anhydrous ethanol and deionized water for 10-20 minutes each in sequence.

[0061] The pressure inside the deposition system after vacuuming in S103 provided by this invention is 5.0 × 10⁻⁶. -4 -5.2×10 -4 Pa.

[0062] The pre-sputtering time in the S103 provided by this invention is 5-10 min, and the laser ablation time is 28-32 min; the substrate and LaNi 0.7Co 0.3 The distance between O3 targets is 50-60 mm, the growth temperature is maintained at 700℃, the oxygen pressure is 1-30 Pa, and the laser sputtering energy density is 2.0 J / cm³. -2 The laser frequency is 8Hz.

[0063] The thin film is taken out under a nitrogen atmosphere in S103 provided by the present invention, and the nitrogen pressure is 1×10⁻⁶. 5 Pa.

[0064] A cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode prepared according to the method described above.

[0065] An application of the cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode in the preparation of an electrocatalytic water desorption oxygen reaction system, characterized in that the system comprises a working electrode, an auxiliary electrode, a reference electrode, and an electrolyte, wherein the working electrode comprises the aforementioned LaNi 0.7 Co 0.3 O3 thin film composite electrode.

[0066] The auxiliary electrode provided by this invention is a platinum wire electrode, the reference electrode is an Hg / HgO electrode, and the electrolyte is a 0.1-1 mol / L potassium hydroxide aqueous solution.

[0067] Example 1

[0068] A method for preparing a cobalt-doped lanthanum nickelate single-crystal thin-film composite electrode includes the following steps:

[0069] (1) Preparation of LaNi 0.7 Co 0.3 O3 sputtering target

[0070] Lanthanum oxide (99.9% purity), nickel oxide, and cobalt tetroxide powder were thoroughly mixed and ground in a molar ratio of 1:0.7:0.3 (lanthanum atoms, nickel atoms, and cobalt atoms). The mixture was then pressed into a cylindrical shape using a mold with a radius and height of 5 mm. The pre-calcination temperature was 900℃, and the sintering time was 12 h. The second sintering temperature was 1200℃, and the time was 12 h, to produce LaNi. 0.7 Co 0.3 O3 target material;

[0071] (2) Substrate pretreatment

[0072] The LaAlO3(001) substrate was ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 15 min each, and then dried with a nitrogen gun before use.

[0073] (3) Preparation of composite electrodes

[0074] The processed substrate and LaNi0.7 Co 0.3 The O3 target is placed on the sample stage of the pulsed laser deposition system, and the substrate and LaNi 0.7 Co 0.3 The distance between the O3 targets is 50 mm. The substrate is shielded with a baffle, and the vacuum level inside the cavity is evacuated to 5.0 × 10⁻⁶. -4 Pa, at an oxygen partial pressure of 26 Pa and a laser energy density of 2.0 J / cm². -2 Under the condition of a laser frequency of 8Hz, a laser pulser was used to treat LaNi 0.7 Co 0.3 O3 target pre-sputtering for 5 min; after pre-sputtering, remove the baffle and perform laser sputtering deposition on the substrate for 30 min; after laser deposition, fill the cavity with nitrogen gas until the pressure is 1×10⁻⁶. 5 After Pa, the sample was removed, LaNi 0.7 Co 0.3 An O3 thin film is fixed onto a glass slide using silver paste, and an ohmic contact is formed by connecting one end of the film with copper paste. Hot melt adhesive is then applied around the perimeter of the film to prepare LaNi. 0.7 Co 0.3 O3 thin film composite electrode.

[0075] The LaNi prepared in Example 1 0.7 Co 0.3 The O3 thin-film composite electrode is used to prepare an OER electrocatalytic system, and its preparation method includes the following steps:

[0076] LaNi 0.7 Co 0.3 The O3 thin film composite electrode is used as the working electrode. Then, the working electrode, the auxiliary electrode, the platinum wire electrode, and the reference electrode, the Hg / HgO electrode, are assembled and placed in the electrolyte, which is a 1 mol / L potassium hydroxide aqueous solution. The system is connected to an electrochemical workstation to obtain the OER electrocatalytic system.

[0077] Test case

[0078] LaNi prepared in Example 1 0.7 Co 0.3 The O3 thin-film composite electrode underwent linear voltammetry and cyclic voltammetry for double-layer capacitance using an OER catalytic system, as shown below. Figure 2 , Figure 3 As shown. The linear voltammetry curves were tested using an OER catalytic system at reversible hydrogen electrode potentials from 1.0 to 1.8 volts, with a scan rate of 50 mV / s. The cyclic voltammetry curves for the double-layer capacitance were tested at reversible hydrogen electrode potentials from 1.28 to 1.48 volts, with scan rates from 50 mV / s to 500 mV / s. A schematic diagram of the double-layer capacitance is shown below. Figure 4As shown, the current density at a potential of 1.38 volts in the cyclic voltammogram of the double-layer capacitance is selected for plotting, and its slope represents the double-layer capacitance value. Electrochemical impedance spectroscopy was measured, and a Nyquist plot was obtained by fitting an equivalent circuit composed of electrolyte resistance (Rs), charge transfer resistance (Rct), and a phase-changing element (CPE). The results are shown below. Figure 5 As shown. Maintaining the control potential at 1.6 volts, the change in current density was tested, and the results are as follows. Figure 6 As shown.

[0079] Depend on Figure 2 It can be seen that the current density is as high as 559.5 μA / cm² at a potential of 1.65 volts. 2 It exhibits good OER performance. (By...) Figure 3 It can be seen that LaNi 0.7 Co 0.3 The large electrochemically active surface area of ​​the O3 thin film indicates a large number of surface active sites and high OER catalytic activity. For example... Figure 4 As shown, the current density at a potential of 1.38 volts in the cyclic volt-ampere curve of the electric double-layer capacitance is plotted, and its slope is equal to the electric double-layer capacitance value of 0.162 mF. From Figure 5 It can be observed that LaNi 0.7 Co 0.3 The Rct of the O3 thin film is 340.8 Ω. (From...) Figure 6 It can be seen that, at a control potential of 1.6 volts, during a test lasting 3000 seconds, LaNi... 0.7 Co 0.3 Although the current density of the O3 thin film showed a slight decreasing trend, it still remained at 150-300 μA / cm. 2 Within the specified range, it is evident that the thin film material prepared by this invention is relatively stable in the electrolyte and is not easily corroded.

[0080] Example 2

[0081] A method for preparing a cobalt-doped lanthanum nickelate single-crystal thin-film composite electrode includes the following steps:

[0082] (1) Preparation of LaNi 0.7 Co 0.3 O3 sputtering target

[0083] Lanthanum oxide (99.9% purity), nickel oxide, and cobalt tetroxide powder were thoroughly mixed and ground in a molar ratio of 1:0.7:0.3 (lanthanum atoms, nickel atoms, and cobalt atoms). The mixture was then pressed into a cylindrical shape using a mold with a radius and height of 5 mm. The pre-calcination temperature was 800℃, and the sintering time was 13 h. The second sintering temperature was 1000℃, and the time was 13 h, to produce LaNi. 0.7 Co 0.3 O3 target material;

[0084] (2) Substrate pretreatment

[0085] The LaAlO3(001) substrate was ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 10 min each, and then dried with a nitrogen gun.

[0086] (3) Preparation of composite electrodes

[0087] The processed substrate and LaNi 0.7 Co 0.3 The O3 target is placed on the sample stage of the pulsed laser deposition system, and the substrate and LaNi 0.7 Co 0.3 The distance between the O3 targets is 52 mm. The substrate is shielded with a baffle, and the vacuum level inside the cavity is evacuated to 5.1 × 10⁻⁶. -4 Pa, at an oxygen partial pressure of 1.3 Pa and a laser energy density of 2.0 J / cm². -2 Under the condition of a laser frequency of 8Hz, a laser pulser was used to treat LaNi 0.7 Co 0.3 O3 target pre-sputtering for 8 min; after pre-sputtering, remove the baffle and perform laser sputtering deposition on the substrate for 28 min; after laser deposition, fill the cavity with nitrogen gas until the pressure is 1×10⁻⁶. 5 After Pa, the sample was removed, LaNi 0.7 Co 0.3 An O3 thin film is fixed onto a glass slide using silver paste, and an ohmic contact is formed by connecting one end of the film with copper paste. Hot melt adhesive is then applied around the perimeter of the film to prepare LaNi. 0.7 Co 0.3 O3 thin film composite electrode.

[0088] The LaNi obtained in Example 2 0.7 Co 0.3 The O3 thin-film composite electrode is used to prepare an OER electrocatalytic system, and its preparation method includes the following steps:

[0089] LaNi 0.7 Co 0.3 The O3 thin film composite electrode is used as the working electrode. Then, the working electrode, the auxiliary electrode, the platinum wire electrode, and the reference electrode, the Hg / HgO electrode, are assembled and placed in the electrolyte, which is a 0.5 mol / L potassium hydroxide aqueous solution. The system is connected to an electrochemical workstation to obtain the OER electrocatalytic system.

[0090] Example 3

[0091] A method for preparing a cobalt-doped lanthanum nickelate single-crystal thin-film composite electrode includes the following steps:

[0092] (1) Preparation of LaNi 0.7 Co0.3 O3 sputtering target

[0093] Lanthanum oxide (99.9% purity), nickel oxide, and cobalt tetroxide powder were thoroughly mixed and ground in a molar ratio of 1:0.7:0.3 (lanthanum atoms, nickel atoms, and cobalt atoms). The mixture was then pressed into a cylindrical shape using a mold with a radius and height of 5 mm. The pre-calcination temperature was 1000℃, and the sintering time was 11 h. The second sintering temperature was 1300℃, and the time was 11 h, to produce LaNi. 0.7 Co 0.3 O3 target material;

[0094] (2) Substrate pretreatment

[0095] The LaAlO3(001) substrate was ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 20 min each, and then dried with a nitrogen gun before use.

[0096] (3) Preparation of composite electrodes

[0097] The processed substrate and LaNi 0.7 Co 0.3 The O3 target is placed on the sample stage of the pulsed laser deposition system, and the substrate and LaNi 0.7 Co 0.3 The distance between the O3 targets is 55 mm. The substrate is shielded with a baffle, and the vacuum level inside the cavity is evacuated to 5.2 × 10⁻⁶. -4 Pa, at an oxygen partial pressure of 13 Pa and a laser energy density of 2.0 J / cm². -2 Under the condition of a laser frequency of 8Hz, a laser pulser was used to treat LaNi 0.7 Co 0.3 O3 target pre-sputtering for 10 min; after pre-sputtering, remove the baffle and perform laser sputtering deposition on the substrate for 32 min; after laser deposition, fill the cavity with nitrogen gas until the pressure is 1×10⁻⁶. 5 After Pa, the sample was removed, LaNi 0.7 Co 0.3 An O3 thin film is fixed onto a glass slide using silver paste, and an ohmic contact is formed by connecting one end of the film with copper paste. Hot melt adhesive is then applied around the perimeter of the film to prepare LaNi. 0.7 Co 0.3 O3 thin film composite electrode.

[0098] The LaNi obtained in Example 2 0.7 Co 0.3 The O3 thin-film composite electrode is used to prepare an OER electrocatalytic system, and its preparation method includes the following steps:

[0099] LaNi 0.7 Co 0.3The O3 thin film composite electrode is used as the working electrode. Then, the working electrode, the auxiliary electrode, the platinum wire electrode, and the reference electrode, the Hg / HgO electrode, are assembled and placed in the electrolyte, which is a 0.1 mol / L potassium hydroxide aqueous solution. The system is connected to an electrochemical workstation to obtain the OER electrocatalytic system.

[0100] Comparative Example 1

[0101] An OER electrocatalytic system includes a working electrode without a LaNiO3 thin film, an auxiliary electrode (platinum wire electrode), and a reference electrode (Hg / HgO electrode). The preparation method is consistent with the OER electrocatalytic system preparation method in Example 1. Tested using the method described in the experimental example of Example 1, its highest current density is 210 μA / cm². 2 Compared to the OER electrocatalytic system prepared in Example 1, the current density is approximately 37% of that in Example 1, while the Rct of the LaNiO3 film is 1109.1 Ω, which is significantly higher than the Rct value of 340.8 Ω measured in Example 1. Therefore, LaNi 0.7 Co 0.3 The OER performance of the O3 thin film composite electrode is much higher than that of the undoped LaNiO3 thin film composite electrode, highlighting the significant progress of the technology of this invention.

[0102] The preparation method provided by this invention uses abundant raw materials, such as LaNi. 0.7 Co 0.3 O3 targets are reusable, easy and quick to operate, highly safe, and conducive to large-scale production. The relationship between the substrate and LaNi can be adjusted. 0.7 Co 0.3 The film thickness is precisely controlled by adjusting the distance between O3 targets and the laser sputtering time, resulting in controllable film thickness, stable performance, and high repeatability.

[0103] LaNi prepared by this invention 0.7 Co 0.3 The O3 thin film composite electrode can be directly used as a reaction electrode. It has good conductivity, good stability in the oxygen evolution reaction of water electrolysis, and high electrocatalytic activity.

[0104] LaNi 0.7 Co 0.3 Compared to undoped LaNiO3 single crystal films, O3 thin films alter the chemical composition of the material and regulate the electronic structure by adjusting the crystal structure, thereby enhancing the orbital hybridization of Ni / Co 3d-O 2p. Therefore, during chemical reactions, they can provide more active sites for electrochemical reactions.

[0105] LaNi provided by the present invention 0.7 Co 0.3The O3 thin-film composite electrode, when applied to an electrocatalytic water electrolysis oxygen evolution reaction system, can effectively catalyze and promote the oxygen evolution reaction.

[0106] This invention utilizes laser pulses to deposit and grow LaNi on a LaAlO3(001) substrate. 0.7 Co 0.3 O3 produces electrode materials with high bonding strength, strong repeatability, and high flatness.

[0107] This invention demonstrates that cobalt-doped lanthanum nickelate engineering can effectively regulate the crystal structure and thus adjust the electronic structure, which is an effective means to enhance the electrocatalytic performance of perovskites and can become an effective and universal strategy for designing next-generation high-performance catalysts for the oxygen evolution reaction in water electrolysis.

[0108] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode, characterized in that, Includes the following steps: Step 1: Preparation of LaNi 0.7 Co 0.3 O3 target material; Lanthanum oxide, nickel oxide, and cobalt tetroxide were mixed according to LaNi 0.7 Co 0.3 After weighing and grinding the O3 molecules according to their stoichiometric molar ratio, they were sintered to produce LaNi. 0.7 Co 0.3 O3 target material; Step 2, substrate pretreatment; The LaAlO3(001) substrate was ultrasonically cleaned and then dried with inert gas before use. Step 3, Preparation of LaNi 0.7 Co 0.3 O3 thin film; The obtained LaNi 0.7 Co 0.3 An O3 target and a LaAlO3(001) substrate were placed in a pulsed laser deposition system. After evacuation, LaNi was deposited under constant oxygen partial pressure and laser energy density. 0.7 Co 0.3 O3 target pre-sputtering is performed, followed by LaNi target pre-sputtering. 0.7 Co 0.3 The O3 target material was laser-ablated and deposited onto a conductive substrate. The LaNi was then removed under a nitrogen atmosphere. 0.7 Co 0.3 O3 thin film; Step four: Prepare the composite electrode; The obtained LaNi 0.7 Co 0.3 The O3 thin film was fixed onto a glass slide using silver paste, and an ohmic contact was formed by connecting one end of the film with copper paste. Hot melt adhesive was applied around the film to prevent the substrate, silver, and copper from being directly exposed to the electrolyte and affecting electrochemical testing. This process yielded LaNi. 0.7 Co 0.3 O3 thin film composite electrode; In step one, two sintering processes are carried out. The first pre-calcination temperature is 800-1000℃ and the sintering time is 11-13h. The second sintering temperature is 1100-1300℃ and the time is 11-13h. In step three, the pre-sputtering time is 5-10 minutes, and the laser ablation time is 28-32 minutes; the substrate and LaNi 0.7 Co 0.3 The distance between O3 targets is 50-60 mm, the growth temperature is maintained at 700℃, the oxygen pressure is 1-30 Pa, and the laser sputtering energy density is 2.0 J / cm³. -2 The laser frequency is 8Hz.

2. The method for preparing the cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode as described in claim 1, characterized in that, The ultrasonic cleaning process in step two includes the following steps: ultrasonic cleaning with acetone, anhydrous ethanol and deionized water for 10-20 minutes each in sequence.

3. The method for preparing the cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode as described in claim 1, characterized in that, In step three, after evacuating to a vacuum, the pressure inside the deposition system is 5.0 × 10⁻⁶. -4 -5.2×10 -4 Pa.

4. The method for preparing the cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode as described in claim 1, characterized in that, In step three, the film is removed under a nitrogen atmosphere with a nitrogen pressure of 1×10⁻⁶. 5 Pa.

5. A cobalt-doped lanthanum nickelate perovskite oxide single-crystal thin-film composite electrode prepared by the method according to any one of claims 1-4.

6. An electrocatalytic water desorption oxygen reaction system prepared by the composite electrode according to claim 5, characterized in that, The electrocatalytic water desorption oxygen reaction system includes a working electrode, an auxiliary electrode, a reference electrode, and an electrolyte, wherein the working electrode includes the LaNi0... 0.7 Co 0.3 O3 thin film composite electrode.

7. The electrocatalytic water desorption oxygen reaction system as described in claim 6, characterized in that, The auxiliary electrode is a platinum wire electrode, the reference electrode is an Hg / HgO electrode, and the electrolyte is a 0.1-1 mol / L potassium hydroxide aqueous solution.

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