CN108075139B

CN108075139B - Ordered membrane electrode based on metal oxide nanobelt and preparation and application thereof

Info

Publication number: CN108075139B
Application number: CN201611014780.0A
Authority: CN
Inventors: 邵志刚; 曾亚超; 俞红梅; 张洪杰; 秦晓平; 宋微; 衣宝廉
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2016-11-18
Filing date: 2016-11-18
Publication date: 2020-11-10
Anticipated expiration: 2036-11-18
Also published as: CN108075139A

Abstract

The invention provides an ordered membrane electrode based on metal oxide nanobelts and a preparation method and application thereof. Firstly, growing Co-OH-CO with regular orientation on a substrate₃Array, then with Co-OH-CO₃Preparing a metal oxide nanorod array by taking the nanorod array as a template, carrying a catalyst on the surface of the metal oxide nanorod array, finally hot-pressing the array on an ion exchange membrane to obtain a membrane electrode, and purifying the membrane electrode, wherein the constructed ordered membrane electrode can be applied to a fuel cell, a solid polymer water electrolysis cell and an integrated renewable fuel cell. The membrane electrode constructed by the invention has the advantages of low catalyst loading capacity, high catalyst utilization rate, easy amplification and the like.

Description

Ordered membrane electrode based on metal oxide nanobelt and preparation and application thereof

Technical Field

The invention relates to a preparation method of an ordered membrane electrode, belonging to the field of fuel cells and solid polymer water electrolysis cells.

Background

With the continuous development of technology and economy, the demand of human society for energy is continuously increased. A clean and efficient energy storage technology becomes a demand of all human beings. The increasingly deteriorating ecological environment forces people to increase research and development efforts.

Hydrogen has become a major research focus of governments and research institutes around the world as a clean, efficient energy carrier. The hydrogen production technology by electrolyzing alkali liquor is the mainstream technology of large-scale hydrogen production. But the electrolyte is easy to run off, and the used asbestos diaphragm is harmful to the environment, so that the technology is eliminated. Solid Polymer Electrolyte (SPE) is a research hotspot due to its advantages of environmental friendliness, high hydrogen production purity, high energy efficiency, easy maintenance, and the like.

Fuel cells are highly efficient energy conversion devices that efficiently convert chemical energy stored in hydrogen gas into electrical energy. At present, fuel cells have been used in various fields such as electric vehicles, distributed power stations, and aviation. Proton exchange membrane fuel cells are receiving wide attention due to their advantages of high power density, fast start-up speed, high conversion efficiency, environmental friendliness, etc.

The integrated renewable fuel cell is an assembly of a solid polymer water electrolysis cell and a fuel cell. When the battery is in the working mode of the solid polymer water electrolytic cell, Oxygen Evolution Reaction (OER) occurs on one side of the electrode, and the electrode becomes an anode; when the cell is in the fuel cell operating mode, an Oxygen Reduction Reaction (ORR) occurs on the electrode side, with the electrode acting as the cathode. The integrated renewable fuel cell has the double functions and characteristics of a solid polymer electrolytic cell and a fuel cell, and is a high-efficiency device for storing and converting electric energy and hydrogen energy.

The Membrane Electrode Assembly (MEA) is the core component of fuel cells, solid polymer water electrolysis cells and integrated renewable fuel cells, and consists of a catalytic layer and a gas diffusion layer which are positioned at two sides of a proton exchange membrane. The Membrane Electrode is mainly classified into a Gas Diffusion Electrode (GDE), a Thin-Film coated Electrode (CCM), and an ordered Electrode represented by a nano-structured Thin Film (NSTF) of 3M company, usa. The GDE is prepared by adopting the processes of screen printing, electrostatic spraying and the like, catalyst slurry consisting of a catalyst, a water repellent and an organic solvent is brushed on a gas diffusion layer, and Naifon solution is sprayed on the surface of a catalyst layer after high-temperature treatment to realize the three-dimensional electrode; CCM is currently generally prepared by spraying, transferring and other processes, in which a slurry composed of a catalyst, an ion conductor resin and an organic solvent is sprayed onto a membrane, or the slurry is sprayed onto other carriers and then transferred onto the membrane to form a membrane-catalyst integrated electrode. The traditional CCM electrode and GDE electrode are mature in preparation process, but the catalyst layer of the electrode is large in thickness, and the catalyst is disorderly stacked, so that the catalyst is high in usage amount and low in catalyst utilization rate. In order to solve the problems of high precious metal consumption and low catalyst utilization rate of the fuel cell, the NSTF electrode developed by 3M company has the characteristics of microscopic order, low catalyst loading capacity and the like, and can effectively reduce mass transfer resistance and improve the utilization rate of the catalyst.

Patent US20110151353a1 describes a method for preparing an NSTF electrode, specifically, metals such as Pt, Mn, Co, Ir are deposited on an ordered nanowhisker array by magnetron sputtering technique, and then the nanorod array carrying a catalyst is transferred to one side or both sides of an ion exchange membrane, and the prepared electrode is suitable for a fuel cell. The electrode prepared by the invention has the advantages of low noble metal consumption, high electrochemical activity, good stability, small mass transfer resistance and the like.

Patent CN201210231717.8 describes a method for preparing a composite electrode, specifically, a highly ordered titanium dioxide nanotube array is prepared by using a secondary anodic oxidation method, and then a platinum-based catalyst is deposited on the titanium dioxide nanotube array. The electrode prepared by the patent has the characteristics of low carrying capacity and thin thickness.

Unlike the above patents, the present invention prepares highly ordered Co-OH-CO by hydrothermal method₃The method comprises the following steps of (1) carrying a metal oxide film on the surface of a nanorod array to form the nanorod array of metal oxide, and finally modifying a catalyst on the surface of the nanorod array of metal oxide. Due to Co-OH-CO₃The nano-rod has special surface appearance, the prepared metal oxide nano-rod is cracked to form an oxide nano-belt in the subsequent treatment, and the prepared electrode is composed of the metal oxide nano-belt loaded with a catalyst. The electrode prepared by the invention has low electrode load and catalytic layerThin thickness and highly ordered catalyst layer.

Disclosure of Invention

The technical scheme adopted by the invention is as follows:

an ordered membrane electrode based on metal oxide nanoribbons: the catalyst layer of the membrane electrode is composed of metal oxide nanobelts with catalyst loaded on one side surface, and the prepared catalyst layer is positioned on one side or two sides of the ion exchange membrane.

The thickness of a catalyst layer of the membrane electrode is 50 nm-5 mu m, the catalyst layer is composed of a metal oxide nanobelt with the width of 10 nm-200 nm, the length of 50 nm-5 mu m and the thickness of 5 nm-100 nm, a catalyst is supported on one side surface of the metal oxide nanobelt, the catalyst forms a continuous film on the surface of the nanobelt, the thickness of the film is 1 nm-500 nm, and one end of the metal oxide nanobelt is fixed on the surface of the ion exchange membrane.

The ion exchange membrane adopted by the membrane electrode is a cation exchange membrane or an anion exchange membrane.

The invention also provides a preparation method of the ordered membrane electrode based on the metal oxide nanobelt, which comprises the following steps:

(1) synthesis of ordered Co-OH-CO on a substrate by hydrothermal method₃A nanorod array;

(2) in the presence of Co-OH-CO₃Carrying metal oxide on the nanorod array to form a nanorod array with the metal oxide;

(3) carrying a catalyst on the nanorod array with the metal oxide;

(4) transferring the nanorod array with the metal oxide carrying the catalyst to one side or two sides of the ion exchange membrane;

(5) and (3) purifying the membrane electrode loaded with the catalyst layer to form the ordered membrane electrode based on the metal oxide nanobelt.

The substrate in the step (1) can be glass, a nickel sheet, a nickel net, a stainless steel sheet or a titanium sheet;

Co-OH-CO in step (1)₃The growth of the array is prepared by a high pressure hydrothermal method, comprising the following steps:

A. preparing a reaction solution, wherein the reaction solution is an aqueous solution containing 1-30mM of ammonium fluoride, 1-30mM of urea and 1-50mM of cobalt nitrate;

B. soaking the substrate in the reaction solution, reacting in a high-pressure reaction kettle at 90-150 deg.C for 30min-24h to obtain Co-OH-CO on the substrate₃And (4) array.

The method for supporting the metal oxide in the step (2) is physical vapor deposition or chemical vapor deposition, the supported metal oxide is one or a composite oxide of more than two of Cr, Ti, Nb, Ta, Mn, W and Sn, and the supporting amount of the oxide is 1 mu g cm^-2～10mgcm^-2。

The method for loading the catalyst in the step (3) comprises physical vapor deposition, chemical vapor deposition, dipping reduction method or dipping sintering method, wherein the loaded catalyst consists of one or more elements of Pt, Pd, Ir, Au, Ru, Ag, Fe, Co, Ni, Cu, Mn and Cr, and the loading amount of the catalyst is 1 mu g cm^-2～100mg cm^-2。

In the step (4), the pressure applied during transfer printing is 0.1-50 MPa, the time is 1 s-30 min, and the temperature is 20-200 ℃.

The membrane electrode purification step in the step (5) is as follows:

(1) pickling the membrane electrode, wherein the adopted acid is nitric acid, sulfuric acid or hydrochloric acid, the concentration is 5 mM-10M, the acid treatment temperature is 20-100 ℃, and the acid treatment time is 1min-24 h;

(2) washing the membrane electrode after acid washing with water at the temperature of 20-100 ℃;

(3) cleaning the membrane electrode in a hydrogen peroxide aqueous solution; the mass concentration of the hydrogen peroxide is 1-10%, and the cleaning temperature is 20-100 ℃;

(4) placing the membrane electrode in sulfuric acid solution for cleaning; the mass concentration of the sulfuric acid is 1-30 wt%, and the cleaning temperature is 20-100 ℃.

The invention also provides the application of the membrane electrode: the prepared electrode can be used for fuel cells or solid polymer water electrolysis cells.

Providing a scheme that:

a preparation method of an ordered membrane electrode based on metal oxide nanobelts comprises the following steps:

1) preparing a reaction solution; the reaction solution is an aqueous solution of ammonium fluoride with the concentration of 1-30mM, urea with the concentration of 1-30mM and cobalt nitrate with the concentration of 1-50 mM;

2) soaking the substrate in the reaction solution, reacting in a high-pressure reaction kettle at 90-150 deg.C for 30min-24h to obtain Co-OH-CO on the substrate₃Array, the substrate used can be glass, nickel sheet, nickel net, stainless steel or titanium sheet;

3) in the presence of Co-OH-CO₃The metal oxide is loaded on the array to form a metal oxide nanorod array, the metal oxide loading method comprises physical vapor deposition and chemical vapor deposition, the loaded metal oxide can be one metal oxide or a composite oxide of several metals of Cr, Ti, Nb, Ta, Mn, W and Sn, and the loading amount of the metal oxide is 1 mu g cm^-2～10mg cm^-2；

4) The catalyst is loaded on the surface of the metal oxide nanorod array by methods such as physical vapor deposition, chemical vapor deposition, dipping reduction or dipping sintering, and the like, and is made of one or more metals of Pt, Pd, Ir, Au, Ru, Ag, Fe, Co, Ni, Cu, Mn and Cr or an alloy of the metals, and the loading amount of the catalyst is 1 mu g cm^-2～100mg cm^-2；

5) Transferring the metal oxide nanorod array carrying the catalyst to one side or two sides of the ion exchange membrane by a transfer method, and removing the substrate; the pressure applied during transfer printing is 0.1-100 MPa, the time is 1 s-30 min, the temperature is 20-200 ℃, and the adopted ion exchange membrane is a cation exchange membrane or an anion exchange membrane;

6) performing acid washing treatment on the ion exchange membrane transferred with the catalyst layer to form an ordered membrane electrode based on metal oxide nanobelts, wherein HCl and H can be selected for acid washing₂SO₄、HNO₃Or HF solution with acid concentration of 1mM-10M, acid washing temperature of 20-100 deg.C, acid washing time of 1min-24 h;

7) washing the acid-washed membrane electrode with water at 25-100 ℃ for 1min-24h to remove acid remaining in the membrane electrode;

8) dipping the electrode in a hydrogen peroxide aqueous solution to remove organic matters introduced in the electrode preparation process, wherein the concentration of the hydrogen peroxide is 1-10%, the dipping temperature is 25-100 ℃, and the dipping time is 1min-24 h;

9) putting the electrode into a sulfuric acid solution at 80 ℃ and boiling for 30 min-1 h;

10) and (3) washing the electrode subjected to the steps for 20s-24h at the washing temperature of 20-100 ℃.

The order means that one end of the metal oxide nanobelt is fixed on the surface of the ion exchange membrane, and the metal oxide nanobelt and the surface of the ion exchange membrane form an angle of 30-90 degrees.

The invention has the following characteristics:

1. the catalyst layer of the ordered membrane electrode prepared by the invention is composed of a metal oxide nanobelt with a catalyst supported on the surface;

2. the membrane electrode prepared by the invention has the characteristics of low consumption of noble metal, adjustable catalyst components and thin catalyst layer thickness;

3. the electrode preparation method described by the invention has the characteristics of mild preparation conditions and simplicity in operation.

Drawings

Fig. 1 is a flow chart of example 1 for preparing an ordered membrane electrode.

FIG. 2a) is the Co-OH-CO prepared in example 1₃Scanning electron microscope image of nanorod array.

FIG. 2b) shows Nb prepared in example 1₂O₅Scanning electron microscope image of nanorod array.

FIG. 2c) shows Pt/Nb prepared in example 1₂O₅Transmission electron microscopy images of nanoribbons.

Fig. 2d) is a plan scanning electron micrograph of the ordered membrane electrode prepared in example 1.

Fig. 2e) is a scanning electron micrograph of a cross section of the ordered membrane electrode prepared in example 1.

Fig. 3a) is an I-V performance curve of the membrane electrode prepared in example 1 in a fuel cell.

Fig. 3b) is a graph comparing the mass ratio power curves of the membrane electrode prepared in example 1 and the conventional electrode.

Fig. 4 is a graph showing the electrode active area in the accelerated decay test between the electrode prepared in example 1 and the conventional electrode, in which fig. 4a is a graph showing the electrode active area in the accelerated decay test between the prepared electrode and the conventional electrode, fig. 4b is a graph showing the electrode active area in the accelerated decay test between the conventional electrode and the conventional electrode, and fig. 4c is a graph showing the retention rate of the electrochemical active area as a function of the number of scanning cycles.

FIG. 5 is a scanning electron microscope image of the catalyst-loaded metal oxide nanorod array prepared in example 2.

Fig. 6 is a scanning electron micrograph of an ordered membrane electrode prepared in example 2.

Figure 7 is a plot of the I-V performance of the ordered membrane electrode prepared in example 2 in a fuel cell.

FIG. 8 is an I-V performance curve for the ordered membrane electrode prepared in example 3 in a water electrolyzer.

Figure 9 is a graph of the performance of the ordered membrane electrode prepared in example 4 in an integrated renewable fuel cell.

Detailed Description

The following examples are further illustrative of the present invention while protecting obvious modifications and equivalents.

Example 1

Preparing Co-OH-CO by using stainless steel as a substrate and adopting a hydrothermal method₃And (4) array. The reaction solution was 10mM ammonium fluoride, 25mM urea, and 5mM cobalt nitrate. Reacting for 5 hours at 120 ℃ in a high-pressure reaction kettle to prepare Co-OH-CO on a substrate₃And (4) array. FIG. 2a) shows the preparation of Co-OH-CO₃Scanning electron micrograph of array. Co-OH-CO can be seen from the figure₃The nanorod array is uniformly grown on the substrate with the growth direction substantially perpendicular to the substrate. Co-OH-CO₃The length of the nano-rod is about 3 mu m, the diameter is about 100nm, and the nano-rod is Co-OH-CO₃The surface density of the nano-rod is 3-4 e⁹/cm²。

By magnetron sputteringInjection method in Co-OH-CO₃Nb loading on arrays₂O₅. The magnetron sputtering power is 100W, the sputtering time is 20min, and the operating pressure is 1.0 Pa. Then adopting magnetron sputtering method to deposit Nb₂O₅Pt is loaded on the surface of the nanorod array, the magnetron sputtering power is 100W, the sputtering time is 10min, and the operating pressure is 1.0 Pa. FIG. 2b) shows Pt/Nb₂O₅Scanning electron microscope image of nanorod array. As can be seen from the figure, Nb supporting platinum₂O₅The nanorod array is perpendicular to the substrate, the length of the array is 2-5 mu m, and the diameter of the nanorod is 100-200 nm. FIG. 2c) is Pt/Nb₂O₅Transmission electron microscopy of nanoribbons shows that Pt is in Nb₂O₅The surface of the nano-belt forms a continuously distributed film.

Nb loaded with platinum₂O₅The nanorod array is transferred to one side of the ion exchange membrane at the transfer pressure of 5MPa, the transfer temperature of 140 ℃ and the transfer time of 1 min. ICP test shows that the platinum loading of the prepared membrane electrode is 40.1 mu g cm^-2The content of Nb was 115.1. mu. gcm^-2。

Removing the stainless steel substrate, and purifying the membrane electrode, wherein the treatment process comprises the following steps: placing the ion exchange membrane loaded with the catalyst layer in 0.5M sulfuric acid solution to remove Co-OH-CO serving as a template₃And (3) array, washing the membrane electrode in deionized water, and removing residual acid liquor. Boiling the membrane electrode in 0.5M sulfuric acid solution at 80 ℃ for 30min, washing away residual acid solution in deionized water, boiling in 5% hydrogen peroxide water solution at 80 ℃ for 30min, boiling the electrode in deionized water at 80 ℃ for 30min, drying the membrane electrode, and packaging into a membrane electrode assembly. Fig. 2d) and 2e) are scanning electron micrographs of the membrane electrode prepared. As can be seen, the prepared membrane electrode is made of Nb loaded with Pt₂O₅Nanobelt composition, Ta supporting Pt after acid washing of the membrane electrode₂O₅The nanorod array cracks to form a nanobelt. Pt-loaded Nb₂O₅The length of the nanobelt is 1-3 μm, the width of the nanobelt is 50-100 nm, the thickness of the nanobelt is 10-20 nm, and the thickness of the catalyst layer is 500 nm.

The prepared ordered membrane electrode is packaged into a membrane electrode assembly, the packaging pressure is 0.5MPa, and the packaging temperature is 140 ℃. The anode of the membrane electrode assembly adopts a gas diffusion electrode, and the Pt/C (70 wt.% of Johnson Matthey) supporting amount of the anode is 0.2mg cm^-2The electrolyte separator is

212 film.

The battery test conditions are as follows: h₂/O₂Flow rate: 50/100 sccm; the temperature of the battery is 75 ℃, the saturation and humidification are carried out, and the back pressure of the battery is 0.1 MPa. FIG. 3 is based on Nb₂O₅The maximum output power of the cell is 382mW cm according to an I-V performance curve in the ordered membrane electrode fuel cell with nanobelts^-2. FIG. 3b) is based on Nb₂O₅Comparison of the performance of the nanoribbon ordered membrane electrode with conventional electrodes based on Pt/C (70 wt.%, JM), it can be seen that Nb-based electrodes were prepared₂O₅Compared with the traditional Pt/C electrode, the mass ratio power of the ordered membrane electrode of the nanobelt is more excellent, and the battery obtains good battery performance under the condition of lower Pt loading capacity.

Example 1 the prepared electrode was subjected to an accelerated decay test. Accelerated decay test conditions: the battery temperature is 75 ℃, and saturation and humidification are performed; the back pressure of the battery is 0.1 MPa; introducing saturated and humidified N into cathode₂The saturated and humidified H is introduced into the anode₂，H₂/N₂Flow rate: 50/100 sccm; potential scanning range (0.6V, 1.0V), scanning speed 50mVs^-1. The electrochemically active area of the electrode was recorded for each 1000 cycles of accelerated decay. Electrochemical active area test conditions: cell temperature 30 ℃, potential sweep range (0.05V, 1.2V), sweep rate 500mVs^-1. FIG. 4c) is the electrochemical active area retention rate as a function of the number of scan cycles, from which it can be seen that Nb-based samples were obtained after undergoing 5000 cycles of accelerated decay testing₂O₅The electrochemical active area of the nanoribbon ordered membrane electrode increased by 110%, while the electrochemical active area of the conventional Pt/C electrode decreased by 32% after undergoing the 5000-cycle accelerated decay test. Accelerated decay tests show that based on Nb₂O₅The ordered membrane electrode of the nanobelt has the advantagesStability of the peptide.

Example 2

Co-OH-CO₃See example 1 for nanorod array preparation.

By adopting a magnetron sputtering method on Co-OH-CO₃Carrying Ta on the array₂O₅. The magnetron sputtering power is 100W, the sputtering time is 20min, and the operating pressure is 1.0 Pa. Then adopting magnetron sputtering method to coat Ta₂O₅Pt is loaded on the surface of the nanorod array, the magnetron sputtering power is 100W, the sputtering time is 10min, and the operating pressure is 1.0 Pa. FIG. 5 shows the prepared platinum-supporting Ta₂O₅Scanning electron microscope image of nanorod array. As can be seen from the figure, Ta supporting platinum₂O₅The nanorod array is perpendicular to the substrate, the length of the array is 2-5 mu m, and the diameter of the nanorod is 100-200 nm.

Ta loaded with platinum₂O₅The nanorod array is transferred to one side of the ion exchange membrane at the transfer pressure of 10MPa, the transfer temperature of 140 ℃ and the transfer time of 2 min. ICP test shows that the Pt supporting amount of the prepared membrane electrode is 50.5 mu g cm^-2The Ta supporting amount is 120.2 μ g cm^-2。

The stainless steel substrate was removed and the membrane electrode was cleaned, as in example 1. Fig. 6 is a scanning electron micrograph of the prepared membrane electrode. As can be seen, the prepared membrane electrode consists of Pt-supported Ta₂O₅The nano-belt has a length of 1-3 μm, a width of 50-100 nm, and a thickness of 10-20 nm.

212 film. The battery test conditions are as follows: h₂/O₂Flow rate: 50/100 sccm; the temperature of the battery is 75 ℃, the saturation and humidification are carried out, and the back pressure of the battery is 0.1 MPa. FIG. 7 shows a Ta-based₂O₅Nano beltThe maximum output power of the ordered membrane electrode fuel cell is 360mW cm^-2. It can be seen that the prepared electrode achieved good cell performance at lower Pt loading.

Example 3

Co-OH-CO₃See example 1 for nanorod array preparation.

By adopting a magnetron sputtering method on Co-OH-CO₃Nb loading on arrays₂O₅. The magnetron sputtering power is 100W, the sputtering time is 20min, and the operating pressure is 1.0 Pa.

H with the concentration of 0.05M is prepared₂IrCl₆Isopropanol solution of Nb₂O₅The nanorod array is immersed in the prepared H₂IrCl₆In the isopropanol solution, the dipping time is controlled to be 3.0min, and the dipping temperature is controlled to be 25 ℃. Taking out Nb after the impregnation is finished₂O₅And (4) absorbing the residual precursor solution on the surface of the nanorod array, and drying at room temperature. Impregnating Nb with catalyst precursor₂O₅The nanorod array is placed in a tubular furnace and is roasted at 450 ℃ for 1 hour to prepare a catalytic layer, and the roasting atmosphere is air.

Hot pressing the catalyst layer on

212(DuPont) film, the pressure at the time of transfer was 3.0MPa and the time was 30s, and the stainless steel substrate was removed after the transfer. The membrane electrode was cleaned and the process flow is as in example 1. IrO is carried after the membrane electrode is acid-washed₂Nb of₂O₅The nanorod array cracks on the Nafion film to form IrO₂@Nb₂O₅A nanoribbon array. ICP test shows that the IrO of the electrode prepared by the method₂The supporting capacity is 172.8 mu g cm^-2. The hydrogen side of the membrane electrode assembly employed a gas diffusion electrode having a Pt/C (70 wt.%, Johnson Matthey) loading of 0.2mg cm^-2. Electrolytic cell test conditions: the electrode areas of the cathode and the anode are both 4.0cm²The temperature of the electrolytic cell is 80 ℃, the water flow at the anode side is 10mL/min, and the operation is carried out under normal pressure. Water electrolytic cell performance figure8, at an electrolytic current density of 1000mA cm^-2The electrolytic voltage was 1.672V.

Example 4

Co-OH-CO₃See example 1 for nanorod array preparation. Nb₂O₅See example 3 for the preparation of nanorod arrays.

The preparation concentration is 0.05M H₂IrCl₆、0.1M H₂PtCl₆The mixed solution of (3) and (3) is prepared by mixing Nb with₂O₅And soaking the nanorod array in the prepared mixed solution, wherein the soaking time is controlled to be 3.0min, and the soaking temperature is 25 ℃. Taking out Nb after the impregnation is finished₂O₅And (4) absorbing the residual precursor solution on the surface of the nanorod array, and drying at room temperature. Impregnating Nb with catalyst precursor₂O₅The nanorod array is placed in a tubular furnace and is roasted at 450 ℃ for 1 hour to prepare a catalytic layer, and the roasting atmosphere is air.

Hot pressing the catalyst layer on

212(DuPont) film, the pressure at the time of transfer was 3.0MPa and the time was 30s, and the stainless steel substrate was removed after the transfer. The membrane electrode was cleaned and the process flow is as in example 1. Nb loaded with catalyst after membrane electrode pickling₂O₅The nanorod array is cracked on the Nafion film to form a nanobelt array. ICP test shows that the IrO of the electrode prepared by the method₂The supporting amount is 192.5 mu g cm^-2The Pt loading was 235.2. mu.g cm^-2. Electrolytic cell test conditions: the electrode areas of the cathode and the anode are both 4.0cm²The GDE was used as the electrode on the cathode side and the platinum-plated titanium felt was used as the anode gas diffusion layer. The operation conditions of the electrolytic cell are as follows: the temperature is 80 ℃, the water flow at the anode side is 10mL/min, and the operation is carried out under normal pressure. The battery test conditions are as follows: h₂/O₂Flow rate: 50/100 sccm; the temperature of the battery is 75 ℃, the saturation and humidification are carried out, and the back pressure of the battery is 0.2 MPa. FIG. 9 is a graph of the performance of an integrated renewable fuel cell prepared in accordance with the example, the cell having a maximum output power of 220mW cm in the fuel cell operating mode^-2(ii) a Electrolysis of water by batteryIn the running mode of the cell, the electrolytic voltage of the cell is 1.633V (@500mA cm)^-2)。

Claims

1. An ordered membrane electrode based on metal oxide nanobelts, which is characterized in that: the catalyst layer of the membrane electrode consists of a metal oxide nanobelt with a catalyst loaded on the surface of one side, and the prepared catalyst layer is positioned on one side or two sides of the ion exchange membrane;

the thickness of a catalyst layer of the membrane electrode is 50 nm-5 mu m, the catalyst layer is composed of a metal oxide nanobelt with the width of 10 nm-200 nm, the length of 50 nm-5 mu m and the thickness of 5 nm-100 nm, a catalyst is supported on one side surface of the metal oxide nanobelt, the catalyst forms a continuous film on the surface of the nanobelt, the thickness of the film is 1 nm-500 nm, and one end of the metal oxide nanobelt is fixed on the surface of the ion exchange membrane;

the preparation process comprises the following steps:

(3) carrying a catalyst on the nanorod array with the metal oxide;

2. The ordered membrane electrode of claim 1, wherein: the ion exchange membrane adopted by the membrane electrode is a cation exchange membrane or an anion exchange membrane.

3. A method for preparing the ordered membrane electrode based on metal oxide nanobelts according to any one of claims 1 to 2, which is characterized in that:

(1) synthesizing ordered Co-OH-on a substrate by a hydrothermal methodCO₃A nanorod array;

(3) carrying a catalyst on the nanorod array with the metal oxide;

4. A method of making an ordered membrane electrode according to claim 3, wherein: the substrate in the step (1) can be glass, a nickel sheet, a nickel net, a stainless steel sheet or a titanium sheet;

5. A method of making an ordered membrane electrode according to claim 3, wherein: the method for supporting the metal oxide in the step (2) is physical vapor deposition or chemical vapor deposition, the supported metal oxide is one or a composite oxide of more than two of Cr, Ti, Nb, Ta, Mn, W and Sn, and the supporting amount of the oxide is 1 mu g cm^-2～10mg cm^-2。

6. The method for producing a membrane electrode according to claim 3, wherein: the method for supporting the catalyst in the step (3) comprises physical vapor deposition, chemical vapor deposition, dipping reduction method or dipping sintering method, and the supported catalyst is Pt, Pd, Ir, Au, Ru, Ag,Fe. One or more elements selected from Co, Ni, Cu, Mn and Cr, and the catalyst loading is 1 μ g cm^-2～100mgcm^-2。

7. The method for producing a membrane electrode according to claim 3, wherein: in the step (4), the pressure applied during transfer printing is 0.1-50 MPa, the time is 1 s-30 min, and the temperature is 20-200 ℃.

8. The method for producing a membrane electrode according to claim 3, wherein: the membrane electrode purification step in the step (5) is as follows:

(1) pickling the membrane electrode with nitric acid, sulfuric acid or hydrochloric acid at a concentration of 5 mM-10M

The temperature is 20-100 ℃, and the acid treatment time is 1min-24 h;

9. Use of a membrane electrode according to any one of claims 1-2, characterized in that: the prepared electrode can be used for fuel cells or solid polymer water electrolysis cells.