阅读说明：本技术 一种原位缺陷修饰Co9S8-多孔氮掺杂碳电极的制备方法 (Preparation method of in-situ defect modified Co9S 8-porous nitrogen-doped carbon electrode ) 是由 黄妞 闫术芳 杨柳 骆禅 张晗 于 2019-10-16 设计创作，主要内容包括：本发明提供一种原位缺陷修饰Co<Sub>9</Sub>S<Sub>8</Sub>-多孔氮掺杂碳电极的制备方法,将钴盐、Tx-100和苯胺等含碳有机物溶于挥发非水溶剂,并加入硫脲作为硫源,获得Co-C-S前躯液；上述前躯液涂布到碳基底上,干燥后先在Ar或N<Sub>2</Sub>气流中退火得到原位硫化钴-碳电极,然后将原位硫化钴电极继续在双氰胺气流下CVD煅烧退火,最终形成原位缺陷修饰Co<Sub>9</Sub>S<Sub>8</Sub>-多孔氮掺杂碳电极。本发明技术方案得到的产品具有设备要求低、所需原料成本低廉、反应条件易于控制、生产工艺简单、所形成的产品一致性好,环境污染小等多个优点,可用于OER和ORR的多功能电催化剂。(The invention provides in-situ defect modified Co 9 S 8 Dissolving carbon-containing organic matters such as cobalt salt, Tx-100, aniline and the like in a volatile non-aqueous solvent, and adding thiourea serving as a sulfur source to obtain a Co-C-S precursor solution; coating the precursor solution on carbon substrate, drying, and adding Ar or N 2 Annealing in airflow to obtain in-situ cobalt sulfide-carbon electrode, and then continuously carrying out CVD calcining annealing on the in-situ cobalt sulfide electrode under dicyandiamide airflow to finally form in-situ defect modified Co 9 S 8 -a porous nitrogen-doped carbon electrode. The product obtained by the technical scheme of the invention has the advantages of low equipment requirement, low cost of required raw materials, easy control of reaction conditions, simple production process, good consistency of the formed product, small environmental pollution and the like, and can be used for preparing the productOER and ORR.)

1. In-situ defect modified Co₉S₈The preparation method of the porous nitrogen-doped carbon electrode is characterized by comprising the following steps:

(1) dissolving cobalt salt, Tx-100 and aniline in a volatile non-aqueous solvent, and adding thiourea to obtain a Co-C-S precursor solution;

(2) coating the precursor solution on a substrate, drying, and placing in Ar gas flow or N₂Annealing and vulcanizing at high temperature in airflow to obtain in-situ Co₉S₈-a carbon electrode;

(3) the above in-situ Co₉S₈CVD calcining annealing of carbon electrode under dicyandiamide gas flow to finally form in-situ defect modified Co₉S₈-a porous nitrogen-doped carbon electrode.

2. The in-situ defect modified Co of claim 1₉S₈The preparation method of the porous nitrogen-doped carbon electrode is characterized in that the volatile nonaqueous solvent comprises ethanol and N, N-dimethylformamide.

3. The in-situ defect modified Co of claim 1₉S₈-a method for the preparation of a porous nitrogen-doped carbon electrode, characterized in that cobaltThe salt, Tx-100, aniline and thiourea were dissolved in a volatile non-aqueous solvent to form a mixed solution having a Co atom concentration of 100 ~ 900 mM, a Tx-100/aniline/non-aqueous solvent volume ratio of 0.03 ~ 2, and a Tx-100/aniline volume ratio of 50 ~ 5.

4. The in-situ defect modified Co of claim 1₉S₈The preparation method of the porous nitrogen-doped carbon electrode is characterized in that the substrate comprises any one of carbon paper, carbon cloth, foamed copper or foamed nickel.

5. The in-situ defect modified Co of claim 1₉S₈-a method for the preparation of a porous nitrogen-doped carbon electrode, characterized in that said drying is carried out by heating to 70 ~ 100 ℃ in air or vacuum.

6. The in-situ defect modified Co of claim 1₉S₈The preparation method of the porous nitrogen-doped carbon electrode is characterized in that the annealing temperature is 600 ~ 1000 ℃, and the reaction time is 0.5 ~ 4 h.

7. The in-situ defect modified Co of claim 1₉S₈-a method for preparing a porous nitrogen-doped carbon electrode, characterized in that the mass ratio of dicyandiamide to metallic cobalt atoms is 5 ~ 1.

8. The in-situ defect modified Co of claim 1₉S₈The preparation method of the porous nitrogen-doped carbon electrode is characterized in that the CVD annealing temperature of the second post-treatment is 400 ~ 700 ℃ and the time is 0.5 ~ 3 h.

Technical Field

The invention relates to an in-situ electrode and preparation thereof, belonging to the field of energy storage and conversion materials and devices.

Background

In order to meet the challenges of traditional energy emission and environmental pollution, the development of efficient electrocatalysts plays a crucial role in the application of green and sustainable energy storage and conversion devices. The general energy storage conversion device involves two reactions, i.e. OER and ORR, and therefore, the development and research of corresponding catalysts are urgent. Transition metal-nitrogen-carbon (M-N-C) or related catalysts have proven to be the most promising bifunctional OER and ORR catalysts. Such catalysts can be classified into composite electrocatalysts composed of monatomic electrocatalysts, transition metal-based particles (including metals, alloys, oxides, nitrides, sulfides, etc.), and carbon materials. For example, Benjamin et al prepared Co from ZIF-67/polyaniline₄N/N doped carbon fiber hybrids. Experiments prove that Co₄The Co-N interface coupling active center formed between the N particles and the nitrogen-doped carbon fiber has good electrocatalytic capability on ORR. By utilizing the synergistic effect between the transition metal-based particles and the carbon carrier and by elaborately designing the precursor of the transition metal-based particles and the change process of the precursor, the synthesized composite material with the perfect combination of the metal sulfide and the nitrogen-doped carbon is one of the key points for preparing the high-efficiency catalyst.

In addition to good bonding conditions inside each part of the composite catalyst, good bonding conditions of the composite catalyst and a conductive substrate (such as foamed nickel, carbon fiber paper and carbon cloth) are another key factor for realizing high stable electrocatalytic performance. Because of the use of insulating polymeric binders (e.g., electrolytes) to powder the catalyst matrix, a significant number of pores (or pores) and active sites will inevitably clog, thus limiting the electrocatalytic performance while exacerbating the surface of the catalyst matrix. If the porous electrocatalyst is grown in situ on the substrate as the working electrode, the above problems can be avoided, charge transfer, mass diffusion and accessibility of the active sites are promoted, and efficient operation is achieved.

Disclosure of Invention

In view of the above, the present invention provides a method for obtaining in-situ defect modified Co by post-treatment₉S₈Preparation method of porous nitrogen-doped carbon electrodeThe method has the advantages of low equipment requirement, low cost of required raw materials, easy control of reaction conditions, simple production process, good consistency of formed products, small environmental pollution and the like, can be used in the fields of adsorption, catalysis, electric energy storage and the like, and has great significance for batch production of in-situ electrodes.

The invention provides a composite in-situ electrode which uses Co-C-S as a precursor solution, is coated on a substrate to form a film, is annealed in inert gas to obtain an in-situ cobalt sulfide-carbon porous carbon film, and then is calcined and annealed under dicyandiamide gas flow to prepare in-situ defect modified Co₉S₈-a method of porous nitrogen doped carbon electrode comprising the steps of:

firstly, dissolving cobalt salt, Tx-100 and aniline or other organic matters in a polar volatile solvent such as N, N-dimethylformamide under the condition of stirring at room temperature, adding thiourea as a sulfur source to obtain a Co-C-S precursor solution, wherein the concentration of Co atoms is 200 ~ 900 mM, the volume ratio of Tx-100 to aniline to a non-aqueous solvent is 0.03 ~ 2, the volume ratio of Tx-100 to aniline is 50 ~ 5, and the volatile non-aqueous solvent comprises ethanol and N, N-dimethylformamide₉S₈-porous nitrogen-doped carbon electrodes lay a good foundation; the thiourea is used as a sulfur source, so that the air pollution can be effectively reduced, and the method is safe, controllable and easy to operate.

And secondly, dripping or spin-coating the precursor on a substrate, such as any one of carbon paper, carbon cloth, copper foam or nickel foam, heating the substrate to 70 ~ 100 ℃ in air or vacuum for quick drying, wherein the step is characterized in that a precursor film layer formed by uniformly mixing Co salt, Tx-100, polyaniline and thiourea is left after the N, N-dimethylformamide is quickly volatilized, and the uniform porous carbon film containing the cobalt sulfide is ensured to be obtained after the subsequent high-temperature annealing reaction.

Thirdly, the precursor film in the second step is put in Ar gas flow or N₂Sintering in air flow at 600 ~ 1000 deg.C for 30min ~ 4h, cooling with furnace, and taking outThus obtaining the composite in-situ electrode of the molybdenum-cobalt sulfide porous carbon film.

Fourthly, reacting the porous carbon film composite in-situ electrode dicyandiamide containing cobalt sulfide obtained in the third step at 400 ~ 700 ℃ for 0.5 ~ 3 hours to obtain in-situ defect modified Co₉S₈-a porous nitrogen-doped carbon electrode.

The mass ratio of the used amount of dicyandiamide to the metallic cobalt atom is 5 ~ 1.

In-situ defect modified Co₉S₈The porous nitrogen-doped carbon electrode is formed by growing Co in situ on a CFP substrate by adopting an easy-to-operate method₉S₈The composite material is a composite material with porous carbon, relates to regulation and control of precursor composition, and is decomposed in Ar atmosphere. Next, a post-treatment method was studied, in which the catalyst prepared in one step was further prepared by using dicyandiamide decomposed gas. The results show that the addition of dicyandiamide makes Co₉S₈The average particle diameter of (A) is greatly reduced, the ratio of Co-N to pyridine-N is sharply increased, and the defect degree of the carbon component is obviously increased.

Drawings

FIG. 1 Co prepared in example 1₉S₈XRD of porous nitrogen-doped carbon electrodes.

FIG. 2 Co prepared in example 1₉S₈SEM of porous nitrogen-doped carbon electrodes, the magnification of the (a) to (c) figures increasing in sequence.

FIG. 3 shows Co prepared in example 1₉S₈Linear sweep voltammogram of a porous nitrogen-doped carbon electrode or a control, wherein (a) is the linear sweep voltammogram of the OER of the electrode prepared in example 1, (b) is the linear sweep voltammogram of the ORR of the electrode prepared in example 1, (c) is the linear sweep voltammogram of the OER of the control prepared in example 1, and (d) is the linear sweep voltammogram of the ORR of the electrode prepared in the control of example 1.

FIG. 4 Co prepared in example 1₉S₈Stability of porous nitrogen-doped carbon electrodes (a) is the long-term OER stability curve measured with a time-of-place method and (b) is the linear sweep voltammogram of OER before and after the stability test.

FIG. 5 Co prepared in example 1₉S₈-Zn-air battery cycling stability of porous nitrogen doped carbon electrodes.

FIG. 6 Co prepared in example 2₉S₈-a linear scanning voltammogram of a porous nitrogen-doped carbon electrode.

FIG. 7 Co prepared in example 3₉S₈-a linear scanning voltammogram of a porous nitrogen-doped carbon electrode.

FIG. 8 Co prepared in example 4₉S₈-a linear scanning voltammogram of a porous nitrogen-doped carbon electrode.

Detailed Description

The method for testing the OER and ORR performance LSV in the embodiment of the invention comprises the following steps: by in-situ Co₉S₈The porous nitrogen-doped carbon electrode is used as a working electrode, the carbon rod is used as a counter electrode, the saturated Hg/HgO electrode is used as a reference electrode, the electrolyte is a 1M KOH aqueous solution, and the scanning speed is 5 mV/s. Oxygen is introduced in OER and ORR tests to naturally saturate oxygen in KOH aqueous solution, and the rotating speed of the disc electrode in the test process is 1600 r.p.m.