阅读说明：本技术 CuS2/Na5NiO4高效析氧催化剂及制备方法 (CuS2/Na5NiO4High-efficiency oxygen evolution catalyst and preparation method thereof ) 是由 颜晓红 杨欢 饶德伟 于 2020-03-10 设计创作，主要内容包括：本发明属于电催化领域,涉及CuS<Sub>2</Sub>/Na<Sub>5</Sub>NiO<Sub>4</Sub>高效析氧催化剂及制备方法。本发明通过引入硫化铜与镍基氧化物构筑结构明晰的异质结构复合材料,一方面通过异质结独特的电子结构调控催化剂的整体电子转移水平,并在催化过程中改变催化剂表面上中间体的吸附和解吸能；另一方面发挥异质结双组分的协同催化作用,共同促进催化剂氧析出活性的提升。(The invention belongs to the field of electrocatalysis, and relates to CuS 2 /Na 5 NiO 4 A high-efficiency oxygen evolution catalyst and a preparation method thereof. According to the invention, a heterostructure composite material with a clear structure is constructed by introducing copper sulfide and nickel-based oxide, so that on one hand, the overall electron transfer level of the catalyst is regulated and controlled through a unique electronic structure of a heterojunction, and the adsorption and desorption energy of an intermediate on the surface of the catalyst is changed in the catalysis process; on the other hand, the catalyst plays a role in the synergistic catalysis of heterojunction double components, and promotes the promotion of the oxygen precipitation activity of the catalyst together.)

1.CuS₂/Na₅NiO₄The high-efficiency oxygen evolution catalyst is characterized in that the CuS₂/Na₅NiO₄The high-efficiency oxygen evolution catalyst is CuS₂/Na₅NiO₄A heterojunction composite material; CuS₂/Na₅NiO₄The heterojunction composite material is used as a catalyst and loaded on a glassy carbon electrode to serve as a working electrode and is used for electrocatalytic oxygen evolution reaction.

2. The CuS of claim 1₂/Na₅NiO₄The preparation method of the high-efficiency oxygen evolution catalyst is characterized by comprising the following specific steps:

(1) weighing nickel chloride hexahydrate, stirring and dissolving the nickel chloride hexahydrate into a nano copper sulfide solution, uniformly mixing the nickel chloride hexahydrate and the nano copper sulfide solution, placing the mixture on a platform stirrer, and stirring the mixture at room temperature to obtain a uniformly mixed solution 1, wherein the molar ratio of the nickel chloride hexahydrate to the nano copper sulfide of the nano copper sulfide solution is as follows: 0.5-0.75: 0.2;

(2) and (2) transferring concentrated ammonia water to the solution 1 obtained in the step (1), continuously stirring until the concentrated ammonia water and the nickel chloride hexahydrate are uniformly mixed to obtain a solution 2, wherein the molar ratio of the concentrated ammonia water to the nickel chloride hexahydrate is 1.5-4.5: 0.5 to 0.75;

(3) transferring the solution 2 prepared in the step (2) into a high-pressure reaction kettle, and putting the reaction kettle into an oven to react for 10 hours at the temperature of 150-180 ℃;

(4) after the reaction is finished, cooling the reaction kettle to room temperature, centrifuging the product, washing the product with water and ethanol, and drying the product in vacuum at room temperature to obtain CuS₂/Na₅NiO₄Anode OER catalyst.

3. The CuS of claim 1₂/Na₅NiO₄The preparation method of the high-efficiency oxygen evolution catalyst is characterized in that in the step (1), the room-temperature stirring time is 10-20 min.

4. The CuS of claim 1₂/Na₅NiO₄The preparation method of the high-efficiency oxygen evolution catalyst is characterized in that in the step (2), the stirring is continued for 5-10 min.

5. The CuS of claim 1₂/Na₅NiO₄The preparation method of the high-efficiency oxygen evolution catalyst is characterized in that in the step (4), water and ethanol are used for washing for 3-5 times, and vacuum drying is carried out for 24 hours at room temperature.

Technical Field

The invention belongs to the field of electrocatalysis, and particularly relates to a high-efficiency oxygen evolution catalyst CuS₂/Na₅NiO₄A heterojunction composite material and a preparation method.

Background

The cost of noble metal-based catalysts for Oxygen Evolution Reactions (OERs) has taken a significant part of new energy conversion devices (such as hydrogen generation by electrolysis of water and metal air batteries), and the development of alternative non-noble metal-based catalysts is of great importance for commercial application of the devices.

Transition metal-based catalysts have been the focus of research due to their abundant resource reserves and low cost, as well as their potential in electrolytic water oxygen evolution reactions. In recent years, research on nickel-based catalysts, such as oxides, selenides, phosphides, hydroxides, oxyhydroxides, and the like of nickel, has been used in the OER field. However, the nickel-based catalyst generally has low electron transfer capability, so that the OER catalytic activity of the nickel-based catalyst is hindered, and the electronic structure needs to be further regulated and controlled so as to improve the oxygen evolution catalytic performance of the nickel-based catalyst.

Aiming at the problems, the invention discloses a simple preparation method of a nickel-based heterojunction catalyst, which constructs a heterostructure composite material with a clear structure by introducing copper sulfide and nickel-based oxide, on one hand, the overall electron transfer level of the catalyst is regulated and controlled by a unique electron structure of a heterojunction, and the adsorption and desorption energy of an intermediate on the surface of the catalyst is changed in the catalysis process; on the other hand, the catalyst plays a role in the synergistic catalysis of heterojunction double components, and promotes the promotion of the oxygen precipitation activity of the catalyst together.

Disclosure of Invention

The invention aims to provide a preparation method of a copper-nickel bimetallic-based heterojunction composite material of an efficient oxygen evolution catalyst.

The specific technical scheme is as follows:

high-efficiency oxygen evolution catalyst CuS₂/Na₅NiO₄The preparation method of the heterojunction composite material comprises the following steps:

(1) preparation of copper sulfide according to the method reported in the literature (M.Zhou, R.Zhang, M.Huang, W. L u, S.Song, M.P.Melanocon, M.Tian, D. L iang and C. L i.A chemical-free multifunctionality [, ], [ 2 ] C⁶⁴Cu]CuS nanoparticule platform for multiplex and electron micro-PET/CT imaging and dot thermal analysis thermal. J.Am.chem.Soc.,2010,132, 15351-15358).

The adopted specific technical scheme is as follows:

weighing copper chloride dihydrate and trisodium citrate dihydrate, adding deionized water, and magnetically stirring at room temperature to dissolve the copper chloride dihydrate and the trisodium citrate dihydrate into a uniform light blue solution; weighing sodium sulfide nonahydrate, and adding deionized water to prepare Na₂S·9H₂O aqueous solution, followed by adding Na₂S·9H₂Quickly adding the O aqueous solution into the light blue solution, and magnetically stirring the mixture at room temperature for reactionUntil the mixed solution turns into dark brown; and transferring the mixed solution into a constant-temperature water bath kettle, heating in a water bath to 90 ℃, reacting to obtain a dark green copper sulfide nanoparticle solution, cooling in an ice-water bath, and finally placing the solution in a refrigerator for later use.

In the light blue solution, the ratio of copper chloride dihydrate and trisodium citrate dihydrate to deionized water is 1 mmol: 0.68 mmol: 180m L.

The Na is₂S·9H₂The volume ratio of the O aqueous solution to the light blue solution is 1: 9, Na₂S·9H₂The concentration of the O aqueous solution was 50 mmol/L.

The reaction time was 5min with magnetic stirring at room temperature.

The water bath is heated to 90 ℃ for reaction for 15 min.

The refrigerator temperature was 4 ℃.

(2) Weighing nickel chloride hexahydrate, stirring and dissolving the nickel chloride hexahydrate into a nano copper sulfide solution, uniformly mixing the solution, placing the solution on a platform stirrer, and stirring the solution at room temperature to obtain a uniformly mixed solution 1;

(3) adding concentrated ammonia water into the solution 1 obtained in the step (2), and continuously stirring until the concentrated ammonia water is uniformly mixed to obtain a solution 2;

(4) transferring the solution 2 prepared in the step (3) into a high-pressure reaction kettle, and putting the reaction kettle into an oven to react for 10 hours at the temperature of 150-180 ℃;

(5) after the reaction is finished, cooling the reaction kettle to room temperature, centrifuging the product, washing the product with water and ethanol, and drying the product in vacuum at room temperature to obtain CuS₂/Na₅NiO₄Anode OER catalyst.

In the step (2), the molar ratio of the nickel chloride hexahydrate to the nano copper sulfide of the nano copper sulfide solution is as follows: 0.5-0.75: 0.2, stirring for 10-20min at room temperature.

In the step (3), the molar ratio of the concentrated ammonia water to the nickel chloride hexahydrate is 1.5-4.5: 0.5-0.75, and continuously stirring for 5-10 min.

And (5) washing with water and ethanol for 3-5 times, and vacuum drying at room temperature for 24 hours.

CuS obtained in the present invention₂/Na₅NiO₄The catalyst has an excellent heterojunction interface, the newly introduced transition metal Cu improves the electronic structure of the catalyst, electron transfer is facilitated, further improvement of the OER performance of the nickel-based catalyst is realized through electronic regulation and dual-component concerted catalysis, complex means such as heat treatment and the like are not needed in the preparation process of the catalyst, the preparation process is simple and convenient, and the catalyst can be prepared repeatedly.

CuS obtained in the present invention₂/Na₅NiO₄The catalyst shows excellent electrochemical OER performance, and the test shows that the prepared optimal CuS₂/Na₅NiO₄The current density of the catalyst in an Oxygen Evolution Reaction (OER) reaches 20mA/cm²The overpotential of time is only 326mV, far exceeding that of commercial RuO₂Performance of OER (20 mA/cm)²The overpotential at (b) was 361 mV).

CuS prepared by the invention₂/Na₅NiO₄The catalyst has low cost, rich raw material sources, safety and no toxicity. The preparation method is simple, the catalyst can be prepared repeatedly, has good OER catalytic performance, and has important prospects in the research of the field of replacing noble metal catalysts for water electrolysis anode OER catalysts in the future.

Drawings

FIG. 1 shows the CuS obtained in example 1₂/Na₅NiO₄XRD pattern of the catalyst.

FIG. 2 shows CuS obtained in examples 1 to 5₂/Na₅NiO₄Graph of Oxygen Evolution Reaction (OER) linear scan (L SV) of catalyst under alkaline electrolyte.

Detailed Description

Reagents and instrumentation: the reagents used in the invention are all analytically pure, and the reagents are directly applied without any special treatment without special description.

Cupric chloride dihydrate (CuCl)₂·2H₂O), sodium sulfide nonahydrate (Na)₂S·9H₂O), trisodium citrate dihydrate (C)₆H₅Na₃O₇·2H₂O), nickel chloride hexahydrate (NiCl)₂·6H₂O)，Ammonia (NH)₃·H₂25-28% of O, the molar concentration is 13.38 mol/L), the potassium hydroxide (KOH) used for electrochemical test is analytically pure, and is purchased from national drug group chemical reagent limited, anhydrous ruthenium oxide (RuO)₂99.9% metals basis, Alfa Aesar), Nafion perfluorinated resin solution (5 wt%, Sigma Aldrich).

Analytical balance (Precisa, XJ220A), centrifuge (hunan xiang instrument, TG16-WS), air-blast drying cabinet (shanghai sperm macro, DFG-9076A), vacuum drying cabinet (shanghai sperm macro, DZF-6090), electrochemical workstation (shanghai chenhua, CHI760E), rotating disk ring electrode device (pone corporation, usa).

Electrochemical test, namely, electrochemical oxygen evolution performance test adopts a Chenghua electrochemical workstation and a three-electrode test system, a glassy carbon electrode loaded with a catalyst is used as a working electrode, a reversible hydrogen reference electrode and a graphite rod electrode are respectively used as a reference electrode and a counter electrode, the catalyst is added into a prepared membrane solution (water: ethanol: 5 wt% Nafion volume ratio is 40: 10: 1), the catalyst solution is dispersed into 3mg/m L by ultrasonic, 10 mu L solution is dripped on the glassy carbon electrode with the diameter of 5mm each time, the glassy carbon electrode is naturally aired, the dripping is repeated twice, and the O-shaped catalyst solution is dripped on the glassy carbon electrode with the diameter of 5mm in O₂Electrochemical OER performance was tested in saturated 1M KOH solution and gave L SV curves at a sweep rate of 5 mV/s.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.

The present invention will be described in detail with reference to specific examples.