阅读说明：本技术 一种多缺陷和活性位点的电催化剂的制备方法 (Preparation method of multi-defect and active site electrocatalyst ) 是由 亓钧雷 林景煌 钟正祥 闫耀天 曹健 冯吉才 于 2019-11-29 设计创作，主要内容包括：一种多缺陷和活性位点的电催化剂的制备方法,本发明涉及电催化剂的制备方法。本发明要解决电解水制氢领域中贵金属催化价格昂贵,储量稀少,在电催化分解水中电催化效率低,长时间使用稳定差,利用粉末类型电催化剂制备电极复杂的问题。方法：一、将金属盐、氟化铵和尿素搅拌溶解于去离子水中,得到混合溶液；二、将导电基底浸渍于混合溶液中,保温反应,得到生长有前驱体的导电基底；三、将反应源和生长有前驱体的导电基底置于化学气相沉积装置中反应,即完成多缺陷和活性位点的电催化剂的制备方法。(The invention relates to a preparation method of an electrocatalyst with multiple defects and active sites, and relates to a preparation method of an electrocatalyst. The invention aims to solve the problems that noble metal catalysis is expensive, the reserves are rare, the electrocatalysis efficiency in electrocatalysis decomposition water is low, the long-time use stability is poor, and the preparation of an electrode by using a powder type electrocatalyst is complicated in the field of hydrogen production by water electrolysis. The method comprises the following steps: firstly, stirring and dissolving metal salt, ammonium fluoride and urea in deionized water to obtain a mixed solution; secondly, dipping the conductive substrate into the mixed solution, and carrying out heat preservation reaction to obtain the conductive substrate on which the precursor grows; and thirdly, placing the reaction source and the conductive substrate with the grown precursor in a chemical vapor deposition device for reaction, and thus completing the preparation method of the multi-defect and active site electrocatalyst.)

1. The preparation method of the multi-defect and active site electrocatalyst is characterized by comprising the following steps of:

firstly, stirring and dissolving metal salt, ammonium fluoride and urea in deionized water to obtain a mixed solution;

the concentration of the metal salt in the mixed solution is 1 mmol/L-500 mmol/L; the concentration of ammonium fluoride in the mixed solution is 1 mmol/L-200 mmol/L; the concentration of urea in the mixed solution is 10 mmol/L-1000 mmol/L;

cleaning the conductive substrate, then soaking the conductive substrate in the mixed solution, reacting for 1-24 h at the temperature of 90-180 ℃, and then naturally cooling to obtain the conductive substrate with the precursor;

thirdly, placing the reaction source and the conductive substrate with the precursor in two temperature zones of a chemical vapor deposition device, heating the reaction source to 150-450 ℃ under the conditions that the pressure is 0.2-2 Torr and the gas flow of argon is 5-100 sccm, and heating the conductive substrate with the precursor to 200-600 ℃;

and fourthly, after the temperature is raised, adjusting the gas flow of argon to be 10 sccm-100 sccm, adjusting the pressure of the argon gas to be 0.1 Torr-1 Torr, then reacting for 5 min-120 min under the condition that the power of a plasma radio frequency power supply is 10W-500W, after the reaction is finished, closing the plasma radio frequency power supply, and cooling to room temperature under the argon atmosphere to obtain the multi-defect and active site electrocatalyst.

2. A method of preparing a multi-defect and active site electrocatalyst according to claim 1, wherein: the cleaning of the conductive substrate in the second step is carried out according to the following steps: ultrasonically cleaning the conductive substrate by hydrochloric acid with the concentration of 0.1-1 mol/L for 1-5 min, ultrasonically cleaning the conductive substrate by ethanol and water for 1-5 min, and finally naturally drying the conductive substrate for later use.

3. A method of preparing a multi-defect and active site electrocatalyst according to claim 1, wherein: and the conductive substrate in the second step is carbon cloth, carbon paper, foamed nickel, foamed copper, foamed cobalt, foamed iron, foamed nickel iron, nickel foil, iron foil, copper foil, cobalt foil or nickel-iron alloy foil.

4. A method of preparing a multi-defect and active site electrocatalyst according to claim 1, wherein: the metal salt in the step one is one or a mixture of several of ferric nitrate, cobalt nitrate, nickel nitrate, ferric nitrate and aluminum nitrate.

5. A method of preparing a multi-defect and active site electrocatalyst according to claim 1, wherein: the reaction source in the third step is NaH₂PO₂·H₂One or a mixture of several of O, sulfur powder and selenium powder.

6. A method of preparing a multi-defect and active site electrocatalyst according to claim 1, wherein: the ratio of the mass of the reaction source in the third step to the area of the working surface of the conductive substrate on which the precursor grows is (0.1-3) g:10cm²。

7. A method of preparing a multi-defect and active site electrocatalyst according to claim 1, wherein: the concentration of the metal salt in the mixed solution in the first step is 1 mmol/L-40 mmol/L; the concentration of ammonium fluoride in the mixed solution in the first step is 1 mmol/L-80 mmol/L; the concentration of the urea in the mixed solution in the first step is 10 mmol/L-200 mmol/L.

8. A method of preparing a multi-defect and active site electrocatalyst according to claim 1, wherein: in the second step, the reaction is carried out for 6 to 10 hours under the condition that the temperature is between 100 and 120 ℃.

9. A method of preparing a multi-defect and active site electrocatalyst according to claim 1, wherein: in the third step, the reaction source is heated to 200-450 ℃ under the conditions that the pressure is 0.5-1 Torr and the flow of argon gas is 50-100 sccm, and the conductive substrate with the precursor is heated to 300-600 ℃.

10. A method of preparing a multi-defect and active site electrocatalyst according to claim 1, wherein: regulating the gas flow of argon gas to be 10 sccm-100 sccm, regulating the pressure of argon gas to be 0.5 Torr-1 Torr, and then reacting for 10 min-120 min under the condition that the power of a plasma radio frequency power supply is 10W-400W.

Technical Field

The invention relates to a preparation method of an electrocatalyst.

Background

At present, the electrocatalytic decomposition of water is a clean, pollution-free and large-scale method, and can prepare high-purity hydrogen. In order to overcome the huge energy barrier in the process of water decomposition by electrocatalysis, a high-efficiency electrocatalyst is often needed to reduce the overpotential of hydrogen evolution reaction and oxygen evolution reaction, so that the total decomposition voltage of the whole reaction system is reduced, and the hydrogen is prepared efficiently under the condition of lower energy consumption. However, the traditional catalysts for electrocatalytic water decomposition are often Pt and RuO₂、IrO₂And the like, which have problems of high price, scarce reserves, and the like. Meanwhile, different electrocatalysts are adopted on the two sides of the cathode and the anode in the electrocatalysis decomposition water, so that the whole electrocatalysis efficiency is not favorable, the long-time use stability is poor, and the total water decomposition potential of the electrocatalysis at present needs to be up to 1.8-2.0V. In addition, in the process of preparing an electrode, the traditional powder type electrocatalyst usually needs to introduce an organic binder, needs a complicated electrode preparation process, and is not beneficial to quickly and efficiently preparing an electrode material.

Disclosure of Invention

The invention provides a preparation method of an electrocatalyst with multiple defects and active sites, aiming at solving the problems that noble metal catalysis in the field of hydrogen production by water electrolysis is expensive, the reserves are rare, the electrocatalysis efficiency in electrocatalysis decomposition water is low, the stability for long-time use is poor, and the preparation of an electrode by using a powder type electrocatalyst is complicated.

The preparation process of electrocatalyst with multiple defects and active sites includes the following steps:

firstly, stirring and dissolving metal salt, ammonium fluoride and urea in deionized water to obtain a mixed solution;

the concentration of the metal salt in the mixed solution is 1 mmol/L-500 mmol/L; the concentration of ammonium fluoride in the mixed solution is 1 mmol/L-200 mmol/L; the concentration of urea in the mixed solution is 10 mmol/L-1000 mmol/L;

cleaning the conductive substrate, then soaking the conductive substrate in the mixed solution, reacting for 1-24 h at the temperature of 90-180 ℃, and then naturally cooling to obtain the conductive substrate with the precursor;

thirdly, placing the reaction source and the conductive substrate with the precursor in two temperature zones of a chemical vapor deposition device, heating the reaction source to 150-450 ℃ under the conditions that the pressure is 0.2-2 Torr and the gas flow of argon is 5-100 sccm, and heating the conductive substrate with the precursor to 200-600 ℃;

and fourthly, after the temperature is raised, adjusting the gas flow of argon to be 10 sccm-100 sccm, adjusting the pressure of the argon gas to be 0.1 Torr-1 Torr, then reacting for 5 min-120 min under the condition that the power of a plasma radio frequency power supply is 10W-500W, after the reaction is finished, closing the plasma radio frequency power supply, and cooling to room temperature under the argon atmosphere to obtain the multi-defect and active site electrocatalyst.

The invention has the beneficial effects that:

1. the electrocatalyst is directly prepared on the conductive substrate, a complex electrode preparation process is not needed, the interface transmission resistance between the active substance and the collector electrode can be optimized, rich contact area between the active substance and electrolyte can be provided, and the electrocatalyst is favorable for quick discharge of gas in the electrocatalysis reaction process.

2. The electrocatalyst of the invention has abundant defects and electrochemical active sites, thereby improving the internal activity, obviously improving the electrocatalytic water decomposition capability, and under the condition of a double-electrode test system which takes KOH solution with the concentration of 1mol/L as electrolyte, the total water decomposition reaction reaches 10mA/cm²Only 1.72V of operating voltage is required for the current density of (1). And at 10mA/cm²Under the condition of constant current test for 12h, the voltage value is still retained to be initial 87.4%, and the stability in long-time use is good.

3. The invention utilizes the radio frequency plasma source, can rapidly prepare the electrocatalysis with multiple defects and multiple active sites, has simple and controllable process and low cost, and has wide application prospect in the field of hydrogen production by electrocatalysis water decomposition.

Drawings

FIG. 1 is a transmission electron micrograph of a multi-defect and active site electrocatalyst prepared according to example one.

Detailed Description

The technical solution of the present invention is not limited to the specific embodiments listed below, and includes any combination of the specific embodiments.