阅读说明：本技术 一种自支撑花状磷化镍/磷酸亚铁异质结构全解水电催化剂的制备方法 (Preparation method of self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-electric catalyst ) 是由 徐玲玲 梁爽 魏波 马萧 代冬梅 于 2019-10-10 设计创作，主要内容包括：一种自支撑花状磷化镍/磷酸亚铁异质结构全解水电催化剂的制备方法,它属于新能源材料领域,具体涉及一种Ni<Sub>2</Sub>P/Fe(PO<Sub>3</Sub>)<Sub>2</Sub>异质结构全解水电催化剂的制备方法。本发明的目的是要解决现有同时催化HER和OER的双功能电催化剂存在电极反应过电位较大,反应动力学过程较慢的问题。制备方法：一、清洗泡沫镍；二、配置溶液；三、水热处理；四、清洗干燥；五、磷化处理。优点：作为工作电极时,当电流密度为10mA·cm<Sup>-2</Sup>时,其析氧过电位低于250mV,当电流密度为-10mA·cm<Sup>-2</Sup>时,析氢过电位低于110mV；本发明主要用于制备自支撑花状磷化镍/磷酸亚铁异质结构全解水电催化剂。(A preparation method of a self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis water-electricity catalyst belongs to the field of new energy materials, and particularly relates to a Ni-based catalyst 2 P/Fe(PO 3 ) 2 A preparation method of a heterostructure full-electrolysis water catalyst. The invention aims to solve the problems of large electrode reaction overpotential and slow reaction kinetic process of the traditional bifunctional electrocatalyst for catalyzing HER and OER simultaneously. The preparation method comprises the following steps: firstly, cleaning foam nickel; secondly, preparing a solution; thirdly, carrying out hydrothermal treatment; fourthly, cleaning and drying; and fifthly, phosphating. The advantages are that: when used as a working electrode, the current density is 10mA cm ‑2 When it is over oxygen evolutionThe potential is lower than 250mV, and when the current density is-10 mA cm ‑2 When the hydrogen evolution overpotential is lower than 110 mV; the method is mainly used for preparing the self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-electric catalyst.)

1. A preparation method of a self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-electric catalyst is characterized by comprising the following steps:

firstly, cleaning foamed nickel: sequentially adopting acetone, ethanol and deionized water to ultrasonically clean the foamed nickel, and then drying to obtain clean foamed nickel;

secondly, preparing a solution: dissolving ferric nitrate and urea in deionized water, and uniformly stirring to obtain a ferric nitrate-urea solution;

thirdly, hydrothermal treatment: placing the ferric nitrate-urea solution into a reaction kettle, obliquely soaking clean foamed nickel into the ferric nitrate-urea solution, and placing the reaction kettle into an air-blowing drying oven for heating reaction to obtain reacted foamed nickel;

fourthly, cleaning and drying: taking out the reacted foam nickel, firstly ultrasonically cleaning the foam nickel by using deionized water, and then drying the foam nickel in a vacuum drying oven to obtain the foam nickel for growing the nickel-based basic nickel-iron carbonate;

fifthly, phosphating treatment: taking sodium hypophosphite as a phosphorus source, respectively placing foamed nickel and sodium hypophosphite for growing nickel-based basic nickel-iron carbonate in a tubular furnace, taking nitrogen as protective gas, discharging air in the tubular furnace by utilizing the nitrogen, and carrying out phosphating treatment in a nitrogen atmosphere to obtain self-supporting flower-shaped Ni₂P/Fe(PO₃)₂A heterostructure full-electrolysis hydro-catalyst.

2. The preparation method of the self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-electric catalyst according to claim 1, characterized in that in the first step, the foamed nickel is firstly ultrasonically cleaned in acetone for 5min to 30min, then ultrasonically cleaned in ethanol for 5min to 30min, finally ultrasonically cleaned in deionized water for 5min to 30min, and then dried to obtain clean foamed nickel.

3. The preparation method of the self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-catalyst according to claim 1, wherein the molar ratio of the ferric nitrate to the urea in the second step is 1-10: 8-12; the volume ratio of the ferric nitrate to the deionized water is (1-10) mmol (10-100) mL.

4. The preparation method of the self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-electric catalyst according to claim 1, which is characterized in that in the third step, a reaction kettle is placed in a forced air drying oven, and heat preservation is carried out at the temperature of 40-120 ℃ for 2-10 h, so that the reacted foamed nickel is obtained.

5. The preparation method of the self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-electric catalyst according to claim 1, characterized in that in the fourth step, the foamed nickel after reaction is taken out, firstly, deionized water is used for ultrasonic cleaning for 5min to 10min, then, the foamed nickel is placed in a vacuum drying oven and dried for 5h to 60h at the temperature of 60 ℃, and the foamed nickel with the grown nickel-based basic nickel carbonate is obtained.

6. The preparation method of the self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-electric catalyst according to claim 1, wherein the mass ratio of the foamed nickel and the sodium hypophosphite of the nickel-based basic nickel iron carbonate growing in the step five is (1-3): 1.

7. The method for preparing the self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-electric catalyst according to claim 6, wherein in the fifth step, sodium hypophosphite and foamed nickel growing nickel-based basic nickel iron carbonate are sequentially placed in a tubular furnace along the flowing direction of nitrogen, the distance between the sodium hypophosphite and the foamed nickel growing nickel-based basic nickel iron carbonate is 1 cm-20 cm, and nitrogen is introduced into the tubular furnace at the flow rate of 10 mL/min-100 mL/min to discharge air in the tubular furnace.

8. The preparation method of the self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-electric catalyst according to claim 6 or 7, which is characterized in that the specific process of carrying out the phosphating treatment in the nitrogen atmosphere in the fifth step is as follows: under the nitrogen atmosphere, the temperature in the tubular furnace is firstly increased to 250-650 ℃ from the room temperature at the heating rate of 1-10 ℃/min, then the temperature is kept for 30-300 min under the conditions of the nitrogen atmosphere and the temperature of 250-650 ℃, and then the tubular furnace is cooled to the room temperature along with the furnace.

Technical Field

The invention belongs to the field of new energy materials, and particularly relates to Ni₂P/Fe(PO₃)₂A preparation method of a heterostructure full-electrolysis water catalyst.

Background

The main energy sources used in the world are fossil fuels, including coal, oil, and natural gas, among others. With the consumption of fossil fuels, the search for alternative energy sources is urgent. Hydrogen is widely regarded as a future fuel, water can be decomposed to produce hydrogen, the only by-product is oxygen, and oxygen plays an important role in industry, and hydrogen produced by electrolyzing water accounts for 3.9% of the total hydrogen supply in the world. Due to the huge power consumption, the research on the low-pressure electrolysis water has important significance.

The current major problem in hydrogen production by water electrolysis is high energy consumption due to the two half reactions of water decomposition, both HER (hydrogen evolution) and OER (oxygen evolution), requiring a reduction in the activation energy barrier to achieve a fast kinetic process. With the increasingly intensive research, higher demands are being made on electrocatalysts having high efficiency and long life. Pt and noble metal oxides (RuO)₂And IrO₂) Is a common commercial catalyst and has unique advantages. However, due to their scarcity and high cost, they are not well suited for large scale practical application to the decomposition of water. Under such circumstances, the development of high-activity, economical high-activity, highly-active electrocatalysts is a current research focus. It would be highly desirable to design a bifunctional electrocatalyst capable of catalyzing both HER and OER because it simplifies the operating system and reduces the overall cost of the equipment. To date, a series of transition metal selenides, oxides, chalcogenides, borides, and phosphides have been used as symmetric bifunctional catalysts for bulk water decomposition, such as NiSe, CoMnO, Ni₃S₂、Co₉S₈@MoS₂Carbon Nanofibers (CNFs), Co₂B. CoP and Ni₂And P. Conductive self-supporting materials such as nickel foam, copper foam, titanium sheet and the likeThe advantages of strong binding force, difficult falling off in the reaction process, small contact resistance and the like are also favored. Of these non-noble metal catalysts, transition metal phosphides have been theoretically calculated and experimentally proved to be better bifunctional catalysts. However, the existing material still has the problem that the electrode reaction overpotential is large (when the current density is 10mA cm)^-2In the time, the oxygen evolution overpotential is generally 300mV), the reaction kinetic process is slow, and the like. Much work remains to be done in developing high performance bifunctional electrocatalysts.

Disclosure of Invention

The invention aims to solve the problems of large overpotential of electrode reaction and slow reaction kinetics process of the traditional bifunctional electrocatalyst for catalyzing HER and OER simultaneously, and provides a preparation method of a self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis electrocatalyst.

A preparation method of a self-supporting flower-shaped nickel phosphide/ferrous phosphate heterostructure full-electrolysis hydro-electric catalyst is specifically completed according to the following steps:

firstly, cleaning foamed nickel: sequentially adopting acetone, ethanol and deionized water to ultrasonically clean the foamed nickel, and then drying to obtain clean foamed nickel;

secondly, preparing a solution: dissolving ferric nitrate and urea in deionized water, and uniformly stirring to obtain a ferric nitrate-urea solution;

thirdly, hydrothermal treatment: placing the ferric nitrate-urea solution into a reaction kettle, obliquely soaking clean foamed nickel into the ferric nitrate-urea solution, and placing the reaction kettle into an air-blowing drying oven for heating reaction to obtain reacted foamed nickel;

fourthly, cleaning and drying: taking out the reacted foam nickel, firstly ultrasonically cleaning the foam nickel by using deionized water, and then drying the foam nickel in a vacuum drying oven to obtain the foam nickel for growing the nickel-based basic nickel-iron carbonate;

fifthly, phosphating treatment: sodium hypophosphite is taken as a phosphorus source, foamed nickel and sodium hypophosphite for growing the nickel-based basic nickel-iron carbonate are respectively placed in a tubular furnace, nitrogen is taken as protective gas, the air in the tubular furnace is discharged by utilizing the nitrogen, and phosphorization is carried out in the nitrogen atmosphereTreating to obtain self-supporting flower-shaped Ni₂P/Fe(PO₃)₂A heterostructure full-electrolysis hydro-catalyst.

The invention has the advantages that: firstly, the self-supporting flower-shaped Ni prepared by the invention₂P/Fe(PO₃)₂When the heterostructure full-electrolysis water catalyst is used as a working electrode, the current density is 10mA cm^-2When the current density is-10 mA cm, the oxygen evolution overpotential is lower than 250mV^-2When the hydrogen evolution overpotential is lower than 110mV, the current density is 10mA cm^-2When the voltage is 1.56V, the total hydrolysis voltage is high; secondly, the self-supporting flower-shaped Ni prepared by the invention₂P/Fe(PO₃)₂The heterostructure full-electrolysis water catalyst grows a great deal of Ni on the surface of the foamed nickel₂P/Fe(PO₃)₂The nanoflower has a unique heterostructure which exposes more active sites, so that more electrolyzed water active centers are provided, the catalytic activity is high, and the problem of slow reaction kinetics is effectively solved; thirdly, the invention self-supporting flower-shaped Ni₂P/Fe(PO₃)₂The preparation process of the heterostructure full-electrolysis water catalyst is simple, the price of raw materials is low, and the repeatability is good.

Drawings

FIG. 1 is a scanning electron microscope photomicrograph of the foamed nickel of the growing nickel-based basic nickel oxycarbonate obtained in step four of example 1;

FIG. 2 is a high power scanning electron microscope image of the foamed nickel of the growing nickel-based basic nickel oxycarbonate obtained in step four of example 1;

FIG. 3 shows self-supporting flower-like Ni prepared in example 1₂P/Fe(PO₃)₂Macroscopic scanning electron micrographs of the heterostructure full hydrolysis hydrocatalyst;

FIG. 4 shows self-supporting flower-like Ni prepared in example 1₂P/Fe(PO₃)₂High power scanning electron micrographs of heterostructure full hydrolysis hydrocatalysts;

FIG. 5 is an X-ray diffraction pattern in which A represents the self-supporting flower-like Ni of the electrode prepared in example 1₂P/Fe(PO₃)₂An X-ray diffraction spectrum of the heterostructure full-hydrolysis electrocatalyst; b represents Ni₂P's standard card; c represents Fe (PO)₃)₂The standard card of (1);

FIG. 6 shows self-supporting flower-like Ni prepared in example 1₂P/Fe(PO₃)₂Transmission electron microscopy of the heterostructure full hydrolysis electrocatalyst;

FIG. 7 is a graph of oxygen evolution performance, wherein ● represents the self-supporting flower-like Ni prepared in example 1₂P/Fe(PO₃)₂Oxygen evolution performance profile of heterostructure full-electrolysis electrocatalyst as working electrode, a-gravy representing self-supporting flower-like Ni prepared with example 2₂P/Fe(PO₃)₂Graph of oxygen evolution performance of heterostructure full-electrolysis electrocatalyst as working electrode, t.X represents self-supporting flower-like Ni prepared in example 3₂P/Fe(PO₃)₂An oxygen evolution performance curve chart when the heterostructure full electrolysis water catalyst is used as a working electrode, wherein ■ shows the oxygen evolution performance curve chart when clean foamed nickel is respectively used as the working electrode;

FIG. 8 is a graph of hydrogen evolution performance, in whichShows the self-supporting flower-like Ni prepared in example 1₂P/Fe(PO₃)₂Hydrogen evolution Performance of the heterostructure Total hydrolysis Hydrocatalyst as a working electrode, shown in solid-solid form in the self-supporting flower-like Ni prepared in example 2₂P/Fe(PO₃)₂Graph of hydrogen evolution performance for heterostructure full-electrolysis electrocatalyst as working electrode, t.X represents the self-supporting flower-like Ni prepared in example 3₂P/Fe(PO₃)₂A hydrogen evolution performance curve chart when the heterostructure full electrolysis water catalyst is used as a working electrode, wherein ■ shows the hydrogen evolution performance curve chart when clean foamed nickel is respectively used as the working electrode;

FIG. 9 shows self-supporting flower-like Ni prepared in example 1₂P/Fe(PO₃)₂A full-hydrolysis performance curve when the heterostructure full-hydrolysis electrocatalyst is used as a working electrode;

FIG. 10 shows self-supporting flower-like Ni prepared in example 1₂P/Fe(PO₃)₂Heterostructure full electrolysis water catalyst as working electrodeA time evolution stability curve, wherein a represents the curve at the 1 st cycle of cyclic voltammetry and B represents the curve at the 3000 th cycle of cyclic voltammetry;

FIG. 11 shows self-supporting flower-like Ni prepared in example 1₂P/Fe(PO₃)₂I-t curve of heterostructure full electrolysis water catalyst as working electrode;

FIG. 12 shows self-supporting flower-like Ni prepared in example 1₂P/Fe(PO₃)₂When the heterostructure full-electrolysis water catalyst is used as a working electrode, a hydrogen evolution stability curve is shown, wherein A represents a curve of a 1 st circle of cyclic voltammetry, and B represents a curve of a 3000 th circle of cyclic voltammetry;

FIG. 13 shows self-supporting flower-like Ni prepared in example 1₂P/Fe(PO₃)₂I-t curve of heterostructure full-electrolysis electrocatalyst as working electrode.

Detailed Description