阅读说明：本技术 一种具有三维结构的高效电催化剂材料及其制备方法与应用 (Efficient electrocatalyst material with three-dimensional structure and preparation method and application thereof ) 是由 *** 黄远 缪振宇 邹杨 孔颖 桑元华 王书华 刘宏 于 2019-10-24 设计创作，主要内容包括：本发明提供了一种具有三维结构的高效电催化剂材料及其制备方法与应用,所述的电催化剂材料是将单组分或者多组分金属基底材料通过在强碱性溶液中进行水热刻蚀制备得到的。其制备方法如下：将预处理后的金属基底材料与强碱性溶液在25-250℃下进行水热反应,反应完成后,经洗涤、干燥得到具有三维结构的高效电催化剂材料。本发明的制备方法的条件温和,工艺简单,对设备要求低；所得的材料用于电解水析氧反应,具有较低的过电位和较好的稳定性等电化学性能。(The invention provides a high-efficiency electrocatalyst material with a three-dimensional structure, and a preparation method and application thereof. The preparation method comprises the following steps: and carrying out hydrothermal reaction on the pretreated metal substrate material and a strong alkaline solution at 25-250 ℃, and washing and drying after the reaction is finished to obtain the high-efficiency electrocatalyst material with a three-dimensional structure. The preparation method has mild conditions, simple process and low requirement on equipment; the obtained material is used for electrolytic water oxygen evolution reaction, and has lower overpotential, better stability and other electrochemical properties.)

1. The high-efficiency electrocatalyst material with a three-dimensional structure is characterized in that the electrocatalyst material is prepared by carrying out hydrothermal etching on a single-component or multi-component metal substrate material in a strong alkaline solution.

2. The high efficiency electrocatalyst material with three dimensional structure of claim 1 wherein the metal substrate material is one of stainless steel, stainless iron, titanium sheet, iron sheet, aluminum sheet, zinc sheet, copper sheet, nickel sheet, aluminum foil, iron foam, titanium foam, nickel foam, cobalt foam, iron nickel foam, nickel cobalt foam, iron cobalt foam, copper foam; the metal substrate material is a three-dimensional substrate, and the thickness of the metal substrate material is 0.01-20 mm.

3. The high efficiency electrocatalyst material having a three-dimensional structure according to claim 1, wherein the strongly basic solution is one of barium hydroxide solution, lithium hydroxide solution, potassium hydroxide solution, sodium hydroxide solution, strontium hydroxide solution, rubidium hydroxide solution, cesium hydroxide solution, francium hydroxide solution, radium hydroxide solution, calcium hydroxide solution, ammonia water; the concentration of the strong alkaline solution is 1-20 mol/L.

4. A method for preparing a high efficiency electrocatalyst material having a three dimensional structure according to any one of claims 1 to 3, comprising the steps of:

and carrying out hydrothermal reaction on the pretreated metal substrate material and a strong alkaline solution at 25-250 ℃, and washing and drying after the reaction is finished to obtain the high-efficiency electrocatalyst material with a three-dimensional structure.

5. The method for preparing a high efficiency electrocatalyst material with three dimensional structure according to claim 4, characterized by the pre-treatment steps of: sequentially carrying out ultrasonic cleaning on the metal substrate material by using acetone, ethanol, hydrochloric acid solution and deionized water for 10-600min, and then carrying out vacuum drying for 0.5-120h at 25-150 ℃; preferably, the vacuum drying temperature is 60 ℃, and the vacuum drying time is 24 hours; the concentration of the hydrochloric acid is 0.1-12 mol/L.

6. The method of claim 4, wherein the ratio of the volume of the strongly basic solution to the area of the metal substrate material is 4-30:1mL/cm²Preferably 10-20:1mL/cm²。

7. The method for preparing a high efficiency electrocatalyst material with three dimensional structure according to claim 4, wherein the temperature of the hydrothermal reaction is 60-220 ℃; the time of the hydrothermal reaction is 0.5-120h, preferably 6-90 h.

8. The method for preparing a high efficiency electrocatalyst material with three dimensional structure according to claim 4, characterized in that the washing is sequentially with deionized water, absolute ethanol.

9. The method for preparing a high efficiency electrocatalyst material with three dimensional structure according to claim 4, wherein the drying is vacuum drying at 25-150 ℃ for 0.5-120 h; preferably, the drying is vacuum drying at 90 ℃ for 24 h.

10. Use of the high efficiency electrocatalyst material having a three-dimensional structure according to any one of claims 1 to 3 as an anode electrocatalyst for aqueous alkaline electrolysis water oxygen evolution reactions.

Technical Field

The invention relates to a high-efficiency electrocatalyst material with a three-dimensional structure, and a preparation method and application thereof, and belongs to the technical field of electrochemistry.

Background

Hydrogen is a novel energy carrier, and has the characteristics of high energy density, environmental friendliness and the like, so that the hydrogen plays an important role in the energy conversion process and is increasingly paid more attention by people. Compared with the prior hydrogen production by fossil fuel, the hydrogen production by electrocatalysis water decomposition is a new hydrogen production way with good prospect, safety, environmental protection. In the process of electrocatalytic water decomposition, the anode Oxygen Evolution Reaction (OER) involves a slow four-electron process to cause reaction hysteresis, so that the OER becomes a rate-limiting step of the water decomposition reaction and reduces the overall efficiency of water electrolysis to produce hydrogen. The key to solve the problem is to develop a novel and efficient electrocatalyst to promote the water decomposition reaction.

Currently, oxides of iridium and ruthenium (IrO)₂Or RuO₂) Isonoble metal-based catalysts are considered to be the most active oxygen evolution reaction electrocatalysts, but their large-scale application is greatly hampered by the high cost due to their scarcity. In order to find inexpensive alternatives, great efforts have been made on transition metal oxides, hydroxides, and even chalcogenides. Electrocatalytically active materials grown in situ on metal substrates have attracted considerable attention due to their strong chemical bond interactions and the absence of organic binders, high electron transfer efficiency and high stability. In addition, a catalyst having a three-dimensional structure may have greater advantages in catalytic sites and bubble transport due to a greater surface area and better hydrophilicity.

In order to realize the practical application of industrial electrocatalysis water decomposition, the preparation of the low-cost electrocatalysts also becomes a difficult point at present. In recent years, several industrialized materials have been used to produce high efficienciesSuch as carbon cloth, stainless steel, nickel foam, iron nickel foam, iron flake, etc., by surface treatment of these materials and growing electrocatalytically active substances on the surface to prepare highly active catalysts for anodic oxygen evolution reactions. For example: chinese patent document CN109954503A discloses a nickel selenide and ternary nickel-iron selenide composite electrocatalyst, which comprises a foamed nickel-iron alloy and a layered electrocatalyst in situ grown on the surface of the foamed nickel-iron alloy, wherein the layered electrocatalyst comprises NiSe₂And NiFe₂Se₄. Chinese patent document CN108554413A provides a three-dimensional multi-level structure high-dispersion nickel-based electrocatalytic material and a preparation method thereof, the method takes foam nickel as a conductive matrix and provides a nickel source required by reaction, urea as a precipitator and ammonium fluoride as an etching agent, a NiAl-LDH/NF precursor grows in situ on the surface of a foam nickel skeleton, and anion H is introduced into the nickel-based electrocatalytic material through an ion exchange method₂PO₄，B(OH)₄Introducing into hydrotalcite layers, and then reducing at high temperature to obtain the three-dimensional multi-level structure high-dispersion nickel-based electrocatalytic material. However, the two preparation methods are complicated and high in cost, and the catalytic activity and stability of these catalysts are still not satisfactory for practical applications.

Therefore, the development of a transition metal-based catalyst with simple preparation process, low cost, high efficiency and stability remains a very challenging issue. At present, no high-efficiency electrocatalyst for forming a three-dimensional structure by etching a single-component or multi-component metal substrate material using a strongly basic solution has been reported.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a high-efficiency electrocatalyst material with a three-dimensional structure, and a preparation method and application thereof. The electrocatalyst material prepared by the invention is applied to water electrolysis oxygen evolution reaction, and has lower overpotential and higher stability. The preparation method is simple, the reaction condition is mild, the requirement on equipment is low, and the cost is low.

The technical scheme of the invention is as follows:

the high-efficiency electrocatalyst material with a three-dimensional structure is prepared by carrying out hydrothermal etching on a single-component or multi-component metal substrate material in a strong alkaline solution.

According to the present invention, preferably, the metal substrate material is one of stainless steel, stainless iron, titanium sheet, iron sheet, aluminum sheet, zinc sheet, copper sheet, nickel sheet, aluminum foil, foamed iron, foamed titanium, foamed nickel, foamed cobalt, foamed iron nickel, foamed nickel cobalt, foamed iron cobalt, and foamed copper.

According to the invention, preferably, the metal substrate material is a three-dimensional substrate, and the thickness of the metal substrate material is 0.01-20 mm.

According to the present invention, preferably, the strongly alkaline solution is one of a barium hydroxide solution, a lithium hydroxide solution, a potassium hydroxide solution, a sodium hydroxide solution, a strontium hydroxide solution, a rubidium hydroxide solution, a cesium hydroxide solution, a francium hydroxide solution, a radium hydroxide solution, a calcium hydroxide solution, and ammonia water.

According to the invention, the concentration of the strongly alkaline solution is preferably 1 to 20 mol/L.

According to the invention, the preparation method of the high-efficiency electrocatalyst material with the three-dimensional structure comprises the following steps:

and carrying out hydrothermal reaction on the pretreated metal substrate material and a strong alkaline solution at 25-250 ℃, and washing and drying after the reaction is finished to obtain the high-efficiency electrocatalyst material with a three-dimensional structure.

According to the preparation method of the present invention, preferably, the pretreatment step is: sequentially and respectively ultrasonically cleaning a metal substrate material by using acetone, ethanol, a hydrochloric acid solution and deionized water for 10-600min to remove organic pollutants on the surface and oxides on the surface of the metal, and then carrying out vacuum drying for 0.5-120h at 25-150 ℃; further preferably, the vacuum drying temperature is 60 ℃, and the vacuum drying time is 24 hours;

preferably, the concentration of the hydrochloric acid solution is 0.1-12 mol/L.

According to the production method of the present invention, it is preferable that the ratio of the volume of the strongly basic solution to the area of the metal base material is 4 to 30:1mL/cm²Go forward toThe step is preferably 10-20:1mL/cm²。

According to the preparation method of the invention, the temperature of the hydrothermal reaction is preferably 60-220 ℃; the hydrothermal reaction time is 0.5 to 120 hours, and more preferably 6 to 90 hours.

According to the preparation method of the invention, preferably, the washing is sequentially washing with deionized water and absolute ethyl alcohol.

According to the preparation method of the invention, preferably, the drying is vacuum drying at 25-150 ℃ for 0.5-120 h; further preferably, the drying is vacuum drying at 90 ℃ for 24 h.

According to the invention, the prepared electrocatalyst material has the micro-morphology of nano-rods, nano-wires, nano-needles, nano-sheets and nano-particles; or nanoparticles and nanosheets are interconnected, etc.

According to the invention, the application of the high-efficiency electrocatalyst material with the three-dimensional structure is used as an anode electrocatalyst for the oxygen evolution of alkaline aqueous solution electrolyzed water.

According to the invention, the application of the electrocatalyst as an anode in the electrolysis of water in an alkaline aqueous solution for oxygen evolution can be carried out according to the prior art; preferably, the step of applying the anode electrocatalyst to the alkaline aqueous solution for water electrolysis to generate oxygen comprises the following steps:

(1) preparation of electrolytic solutions

Weighing 56.1g of potassium hydroxide, dissolving the potassium hydroxide in a beaker filled with 400mL of distilled water, stirring and dissolving for 10min under magnetic stirring to form a uniform and transparent solution, then pouring the solution into a 1000mL volumetric flask, fixing the volume to the scale mark of the volumetric flask to form a 1mol/L potassium hydroxide solution, taking the uniform 100mL potassium hydroxide solution, introducing oxygen for half an hour to remove other dissolved gases in the solution to form an oxygen-saturated potassium hydroxide solution;

(2) oxygen evolution by electrolysis of water

A three-electrode system is built in an electrolytic cell, the oxygen saturated potassium hydroxide solution is used as an electrolyte solution, the synthesized high-efficiency electro-catalyst material with a three-dimensional structure is used as a working electrode, a double-salt bridge silver/silver chloride electrode is used as a reference electrode, and a platinum sheet is used as a counter electrode to carry out electrochemical water decomposition.

The invention has the technical characteristics and beneficial effects that:

1. the synthesis method of the electrocatalyst material is simple, the electrocatalyst material with excellent final performance can be prepared by only carrying out simple hydrothermal etching reaction and controlling the concentration of reactants, the reaction time, the reaction temperature and the like, the preparation conditions are mild, the process is simple, the requirement on equipment is low, and the cost is low; the preparation method is suitable for various industrialized single-metal or multi-metal substrate materials, and the electrocatalyst with a three-dimensional structure can be obtained through hydrothermal reaction in an alkaline solution with a proper concentration.

2. The invention selects cheap single-component or multi-component metal with excellent conductivity and three-dimensional framework as the substrate material, the used raw material has larger content in the earth, wide source, large-scale production in industry and low price.

3. The electrocatalyst material prepared by the invention has a stable three-dimensional structure, and the micro-morphology is nano rods, nano wires, nano needles, nano sheets and nano particles; or the nano particles and the nano sheets are mutually connected, so that the nano particles have higher specific surface area, lower overpotential and higher stability. The nickel hercynite/nickel oxyhydroxide material prepared by the stainless steel substrate has the current density of 10mA/cm²The overpotential is only 259 mV; the electro-catalyst material prepared by the foamed iron-nickel substrate has the current density of 50mA/cm²The overpotential is only 310mV, and the stability is measured by a chronoamperometric test method at the corresponding 10mA/cm²And 50mA/cm²The catalytic activity can be maintained above 48h under the voltage.

Drawings

FIG. 1 is a Scanning Electron Microscope (SEM) image of 304 stainless steel used in the examples.

Fig. 2 is an X-ray diffraction (XRD) pattern of the high efficiency electrocatalyst material having a three-dimensional structure prepared in example 1.

Fig. 3 is a Raman spectrum of the high efficiency electrocatalyst material having a three-dimensional structure prepared in example 1.

Fig. 4 is a Scanning Electron Microscope (SEM) image of the high efficiency electrocatalyst material with a three-dimensional structure prepared in example 1.

Fig. 5 is a Scanning Electron Microscope (SEM) image of the high efficiency electrocatalyst material with three-dimensional structure prepared in example 2.

Fig. 6 is a Scanning Electron Microscope (SEM) image of the high efficiency electrocatalyst material with three-dimensional structure prepared in example 3.

FIG. 7 is a linear voltammogram of an oxygen evolution reaction of the electrocatalyst materials prepared in examples 1 to 3 and comparative examples 1, 2 in a 1mol/L potassium hydroxide solution saturated with oxygen.

Fig. 8 is a Scanning Electron Microscope (SEM) image of the high efficiency electrocatalyst material with three-dimensional structure prepared in example 4.

Fig. 9 is a Scanning Electron Microscope (SEM) image of the high efficiency electrocatalyst material with three-dimensional structure prepared in example 5.

FIG. 10 is a linear voltammogram of an oxygen evolution reaction of the electrocatalyst materials prepared in examples 4 to 5, comparative examples 1 and 3 in a 1mol/L potassium hydroxide solution saturated with oxygen.

FIG. 11 is a graph of the stability of the high efficiency electrocatalyst materials with three-dimensional structures prepared in examples 1 and 5 in 1mol/L potassium hydroxide solution saturated with oxygen.

Detailed Description

The invention is further illustrated, but not limited, by the following examples.

Meanwhile, the experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents, materials and equipment are commercially available, unless otherwise specified.