Preparation method of integrated doped perovskite oxide electrode

Abstract

The invention discloses a preparation method of an integrated doped perovskite oxide electrode. FTO (Fluorine-doped Tin Oxide) is used as a current collector; according to the preparation method, A-site doped ABO3 (AB1-xB'xO3) is taken as a functional FTO (Fluorine-doped Tin Oxide) as an active component, the AB1-xB'xO3 active component is directly grown on the surface of the functional FTO in situ by adopting an in-situ growth method technology so as to realize no addition of non-active components and high stability between the active component and a current collector, the method is simple to operate, the reaction energy consumption is reduced, and the prepared doped perovskite oxide is relatively compact in surface and relatively good in stability. No obvious granular oxide exists, the exposed area of active components can be increased, the catalytic activity is improved, the impedance of the electrode is smaller than that of an electrode coated with traditional powder slurry, and transmission of electrons is better facilitated.

Description

Technical field:

[0001] The present invention relates to the technical field of perovskite oxide electrodes, and in particular to a method for preparing an integrated doped perovskite oxide electrode. Background technology:

[0002] Perovskite oxides are composed of ABO₃, where the A site is typically occupied by a rare earth metal or alkaline earth metal, while the B site is occupied by a transition metal. These materials show great potential in both the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). However, compared to the OER activity, the ORR activity still lags significantly behind. Recent studies have shown that surface engineering strategies can effectively improve the bifunctional catalytic activity of ABO₃, primarily due to the electronic structure. From an electronic structural perspective, B-site metal ions have a significantly stronger influence on the material's band gap than A-site ions. Studies have shown that the intrinsic OER / ORR activity of perovskite oxides is closely related to the electron occupancy of the eg orbital and the covalent nature of the BO bond. When the electron occupancy of the eg antibonding orbital of the B-site metal approaches 1, the covalent nature of the BO bond is effectively enhanced, significantly improving the bifunctional catalytic activity of the material. Therefore, controlled substitution of B-site cations has become an effective strategy for optimizing the catalytic performance of ABO₃.

[0003] Although perovskite catalysts have made significant breakthroughs in basic research in recent years, their practical application in electrochemical energy storage and energy conversion devices still faces key technical bottlenecks. Traditional ABO3 catalysts are mostly powder-based, and their preparation methods are mainly solid-phase synthesis, mechanical synthesis, hydrothermal synthesis, sol-gel method, etc. Traditional powder catalysts need to be compounded with auxiliary materials such as conductive substrates and polymer binders during the electrode preparation process. Their manufacturing mostly adopts the "slurry coating" process, which is: first, the nano-catalyst powder is mechanically mixed with conductive carbon (such as acetylene black), polymer binder (usually Nafion) and solvent to form a slurry, and then loaded on the surface of the conductive substrate by dripping or blade coating to prepare an electrode.

[0004] However, this "slurry coating" process has the following disadvantages: 1) Excessive addition of inactive components (binder and conductive agent) leads to a significant decrease in unit mass activity; 2) Organic binders are easily degraded in a highly oxidizing working environment, causing the active material to peel off; 3) The randomly stacked particle structure seriously hinders the effective construction of the three-phase interface (solid-liquid-gas), resulting in low mass transfer efficiency and sluggish reaction kinetics; 4) The weak bonding between the powder and the current collector causes structural instability during cycling. These structural defects ultimately manifest as a decrease in catalytic activity of the electrode, insufficient durability, and reduced device energy efficiency. Summary of the invention:

[0005] The purpose of the present invention is to provide a method for preparing an integrated doped perovskite oxide electrode.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for preparing an integrated doped perovskite oxide electrode, the method comprising the following steps:

[0008] (a) Using acetates of metals A and B as raw materials and deionized water as solvent, ultrasonically stirring and stirring until a homogeneous solution A is formed; then adding a certain proportion of acetate doped with metal B' ions, ultrasonically stirring and stirring until a homogeneous solution B is formed; wherein metal A is one of lanthanum, barium, and calcium; metal B is one of cobalt, nickel, manganese, and copper; wherein metal B' is one of cobalt, nickel, manganese, and copper and different from metal B, and the atomic ratio of metal B to metal B' is 9:1 to 6:4;

[0009] (b) Using FTO as a current collector, immersing it in acetone, ethanol, and deionized water for a certain period of time, followed by ultrasonic treatment, blowing it dry with nitrogen, and then placing it in an air plasma cleaner for a certain period of time to obtain a surface hydroxylated FTO current collector; wherein the air plasma cleaner treatment time is 1-10 minutes, the power is 10%-80%, and the air flow rate is 200-1000 mL / min;

[0010] (c) placing the hydroxylated FTO current collector obtained in step (b) in a quaternary ammonium salt solution of a certain concentration under an inert atmosphere and vacuum conditions to react to obtain a functionalized FTO current collector; wherein the quaternary ammonium salt is one of tetramethylammonium hydroxide and tetraethylammonium hydroxide, or both of them are added in a molar ratio of 0.5:1 to 2:1; the inert atmosphere is one of argon or nitrogen, and the vacuum degree is controlled in the range of 1 Pa to 0.1 MPa;

[0011] (d) placing the functionalized FTO current collector obtained in step (c) in solution B prepared in step (a), allowing it to rest for a certain period of time, and then taking out the sample for later use;

[0012] (e) The solidified sample obtained in step (d) is placed in a vacuum inert atmosphere and calcined at a high temperature by a programmed temperature rising method to obtain AB 1-x B' x O3 / FTO integrated electrode; wherein x is the doping content of metal B', X = 0.1~0.4, the inert gas is one of argon or nitrogen, the vacuum is controlled in the range of 1Pa~0.1MPa, the programmed temperature is increased at 1℃ / min to 200℃ and kept at this temperature for 1 hour, then increased at 1℃ / min to 300-400℃ and kept at this temperature for 2 hours.

[0013] Preferably, the concentration of the quaternary ammonium salt solution in step (c) is 8-12 wt %.

[0014] The beneficial effects of the present invention are as follows:

[0015] 1) The present invention uses FTO as the current collector, and the B-doped ABO3 (AB 1-x B' x O3) is the active component, and AB is directly grown on the functionalized FTO surface using in situ growth technology. 1-x B' x O3 active components are used to achieve no addition of inactive components and high stability between the active components and the current collector. The operation is simple and no special equipment is required. A covers lanthanum, barium, and calcium; B covers cobalt, nickel, manganese, and copper. The elements covered are wide and the preparation method is universal.

[0016] 2) The calcination temperature used in preparing the integrated electrode of the present invention is 300-400°C, which is lower than the traditional perovskite oxide preparation temperature of 600°C and above, thereby reducing the reaction energy consumption.

[0017] 3) The surface of the prepared doped perovskite oxide is relatively dense, without obvious granular oxides, which can increase the exposed area of ​​the active components and improve the catalytic activity.

[0018] 4) The impedance of the doped perovskite oxide integrated electrode prepared by the present invention is smaller than that of the traditional powder slurry coated electrode, which is more conducive to the transmission of electrons.

[0019] In summary, the present invention uses FTO as the current collector, B-doped ABO3 (AB 1-x B' x O3) is the active component, and AB is directly grown on the functionalized FTO surface using in situ growth technology. 1-x B' x O3 active components are added to achieve no addition of inactive components and high stability between the active components and the current collector. This method is simple to operate and reduces reaction energy consumption. The surface of the prepared doped perovskite oxide is relatively dense, without obvious granular oxides, which can increase the exposed area of ​​the active components and improve the catalytic activity. Its impedance is smaller than that of the traditional powder slurry coated electrode, which is more conducive to the transmission of electrons. Description of the drawings:

[0020] Figure 1 The LaNi prepared in Example 1 0.8 Mn 0.2 SEM image of O3 / FTO electrode;

[0021] Figure 2 LaNiO3 and LaNi prepared in Example 1 0.8 Mn 0.2XRD pattern of O3 / FTO;

[0022] Figure 3 The LaNi prepared in Example 1 0.8 Mn 0.2 O3 / FTO integrated electrode and traditional powder electrode LaNi 0.8 Mn 0.2 Impedance comparison chart of O3;

[0023] Figure 4 The BaNi prepared in Example 2 0.8 Mn 0.2 SEM image of O3 / FTO electrode;

[0024] Figure 5 The LaNi prepared in Example 3 0.8 Mn 0.2 SEM image of O3 / FTO integrated electrode;

[0025] Figure 6 The LaNi prepared in Example 4 0.8 Cu 0.2 SEM image of O3 / FTO integrated electrode.

[0026] Figure 7 The BaNi prepared in Example 2 0.8 Mn 0.2 O3 / FTO integrated electrode and traditional powder electrode BaNi 0.8 Mn 0.2 Impedance comparison chart of O3;

[0027] Figure 8 The LaNi prepared in Example 3 0.8 Mn 0.2 O3 / FTO integrated electrode and traditional powder electrode LaNi 0.8 Mn 0.2 Impedance comparison chart of O3O;

[0028] Figure 9 The LaNi prepared in Example 4 0.8 Cu 0.2 O3 / FTO integrated electrode and traditional powder electrode LaNi 0.8 Cu 0.2 Impedance comparison chart of O3. Specific implementation method:

[0029] The following is a further description of the present invention, but not a limitation of the present invention.

[0030] Example 1: LaNi 0.8 Mn 0.2Preparation of O3 / FTO integrated electrode

[0031] Follow these steps:

[0032] (1) Using acetates of metallic La and metallic Ni as raw materials and deionized water as solvent, ultrasonication and stirring are performed until a homogeneous solution A is formed; a certain proportion of acetate of doping ion Mn is added to the homogeneous solution A to form a homogeneous solution B, wherein the atomic ratio of metallic Ni to metallic Mn is 8:2;

[0033] (2) Using FTO as the current collector, it was immersed in acetone, ethanol, and deionized water for ultrasonic treatment for 30 minutes, blown dry with nitrogen, and then placed in an air plasma cleaner for 1 minute to obtain a surface hydroxylated FTO current collector; wherein the power of the air plasma cleaner was 80% and the air flow rate was 200 mL / min;

[0034] (3) preparing a 10 wt.% tetramethylammonium hydroxide salt solution and placing the hydroxylated FTO current collector obtained in step (2) therein, reacting for 2 h under an argon atmosphere and a vacuum degree of 1 Pa, thereby obtaining a functionalized FTO current collector;

[0035] (4) placing the functionalized FTO current collector obtained in step (3) into solution B prepared in step (1), leaving it to rest for 30 minutes, and then taking out the sample for later use;

[0036] (5) The solidified sample obtained in step (4) is placed in a vacuum inert atmosphere and calcined at high temperature using a programmed temperature rising method to obtain LaNi 0.8 Mn 0.2 O3 / FTO integrated electrode; the inert gas is argon, the vacuum degree is controlled in the range of 0.1MPa, the temperature is programmed to rise at 1℃ / min to 200℃ and keep constant at this temperature for 1 hour, then rise to 300℃ at 1℃ / min and keep constant at this temperature for 2 hours.

[0037] The prepared electrodes were physically characterized and the results are shown in the accompanying figures. Figure 1 It's LaNi 0.8 Mn 0.2 SEM image of O3 / FTO integrated electrode, from which we can see the prepared material LaNi 0.8 Mn 0.2 O3 is evenly distributed on the FTO surface, and the surface is relatively flat without obvious granularity. This shows that the method of the present invention can be used to prepare an integrated electrode of perovskite oxide, and the present invention is feasible. Figure 2 LaNiO3 / FTO and LaNi 0.8 Mn 0.2 XRD patterns of O3 / FTO, LaNi 0.8 Mn0.2 O3 has obvious characteristic derivative peaks. By comparing with LaNiO3, it can be seen that LaNi 0.8 Mn 0.2 The O3 characteristic peak shifted negatively, which was attributed to the doping of Mn ions. Figure 3 It's LaNi 0.8 Mn 0.2 O3 / FTO integrated electrode and powdered LaNi 0.8 Mn 0.2 The impedance comparison chart of the O3 powder slurry electrode [see Yong Rong Sun, Xue Zhang, Li Guang Wang, Zhi Kai Liu, Ning Kang, Ni Zhouhou, Wen Long You, Jia Li, Xue-Feng Yu, Lattice contraction tailoring inperovskite oxides towards improvement of oxygen electrode catalytic activity, Chemical Engineering Journal 2021, 421, 129698.] shows that the integrated electrode greatly promotes the rapid transmission of electrons because the active material is in situ grown in the FTO current collector.

[0038] Example 2: BaNi 0.8 Mn 0.2 Preparation of O3 / FTO integrated electrode

[0039] Refer to Example 1, except that the metal La is replaced by Ba.

[0040] Example 3: LaNi 0.8 Mn 0.2 Preparation of O3 / FTO integrated electrode

[0041] Refer to Example 1, except that the tetramethylammonium hydroxide salt solution in step (3) is replaced by a solution of tetramethylammonium hydroxide and tetraethylammonium hydroxide mixed in a ratio of 0.5:1.

[0042] Example 4: LaNi 0.8 Cu 0.2 Preparation of O3 / FTO integrated electrode

[0043] Refer to Example 1, except that the doping ion Mn in step (1) is replaced by Cu.

[0044] The SEM images of the electrodes prepared in Examples 2-4 are shown in Figure 4-Figure 6,From the figure, we can see that the prepared active components are evenly distributed on the ,FTO surface, the surface is relatively flat, and there is no obvious ,granularity.

Claims

1. A method for preparing an integrated doped perovskite oxide electrode, characterized in that: The method comprises the following steps: (a) using acetates of metals A and B as raw materials and deionized water as solvent, ultrasonically stirring and mixing until a homogeneous solution A is formed; then adding acetate doped with metal B' ions in a certain proportion, ultrasonically stirring and mixing until a homogeneous solution B is formed; wherein Metal A is one of lanthanum, barium, and calcium; Metal B is one of cobalt, nickel, manganese, and copper; Metal B' is one of cobalt, nickel, manganese, and copper and is different from Metal B, and the atomic ratio of Metal B to Metal B' is 9:1 to 6:4; (b) Using FTO as a current collector, immersing it in acetone, ethanol, and deionized water for a certain period of time, followed by ultrasonic treatment, blowing it dry with nitrogen, and then placing it in an air plasma cleaner for a certain period of time to obtain a surface hydroxylated FTO current collector; wherein the air plasma cleaner treatment time is 1-10 minutes, the power is 10%-80%, and the air flow rate is 200-1000 mL / min; (c) placing the hydroxylated FTO current collector obtained in step (b) in a quaternary ammonium salt solution of a certain concentration under an inert atmosphere and vacuum conditions to react to obtain a functionalized FTO current collector; wherein the quaternary ammonium salt is one of tetramethylammonium hydroxide and tetraethylammonium hydroxide, or both of them are added in a molar ratio of 0.5:1 to 2:1; the inert atmosphere is one of argon or nitrogen, and the vacuum degree is controlled in the range of 1 Pa to 0.1 MPa; (d) placing the functionalized FTO current collector obtained in step (c) in solution B prepared in step (a), allowing it to rest for a certain period of time, and then taking out the sample for later use; (e) The solidified sample obtained in step (d) is placed in a vacuum inert atmosphere and calcined at a high temperature by a programmed temperature rising method to obtain AB 1-x B' x O3 / FTO integrated electrode; wherein x is the doping content of metal B', X = 0.1~0.4, the inert gas is one of argon or nitrogen, the vacuum is controlled in the range of 1Pa~0.1MPa, the programmed temperature is increased at 1℃ / min to 200℃ and kept at this temperature for 1 hour, then increased at 1℃ / min to 300-400℃ and kept at this temperature for 2 hours.

2. The method according to claim 1, characterized in that The concentration of the quaternary ammonium salt solution is 8-12 wt%.

Images