Search

CN-117623402-B - Vacancy defect Co3O4Preparation method and application thereof

CN117623402BCN 117623402 BCN117623402 BCN 117623402BCN-117623402-B

Abstract

The application discloses a vacancy defect Co 3 O 4 , a preparation method and application thereof. The preparation method of the vacancy defect Co 3 O 4 comprises the steps of calcining cobalt oxalate at a high temperature of 400-1000 ℃ for 0.5-4 h, and immediately placing the calcined cobalt oxalate in a cooling environment for rapid cooling after the high-temperature calcination is finished, so as to obtain the Co 3 O 4 with the vacancy defect. The preparation method of the vacancy defect Co 3 O 4 is simple and convenient, can produce the vacancy defect Co 3 O 4 on a large scale, can meet the use requirement of electrolytic water reaction, and solves the problems of high requirement on instruments and equipment, complex subsequent treatment process and high cost of the existing defect Co 3 O 4 preparation.

Inventors

  • BIAN HAIDONG
  • ZHANG ZHEMING
  • WANG ZHIZHOU

Assignees

  • 北京理工大学深圳汽车研究院(电动车辆国家工程实验室深圳研究院)

Dates

Publication Date
20260512
Application Date
20231108

Claims (9)

  1. 1. The preparation method of the vacancy defect Co 3 O 4 is characterized by comprising the steps of calcining cobalt oxalate at a high temperature of 400-1000 ℃ for 0.5-4 hours, immediately placing the calcined cobalt oxalate in a cooling environment for rapid cooling after the high-temperature calcination is completed, and obtaining Co 3 O 4 with the vacancy defect; the cooling environment is room temperature water; Cooling is performed with an amount of at least 100mL of water per 0.1g of Co 3 O 4 , or rapid cooling is performed with flowing water.
  2. 2. The method of claim 1, wherein the cobalt oxalate is recovered from waste lithium cobalt oxide positive electrode powder by oxalic acid treatment.
  3. 3. The method for preparing the cobalt oxalate according to claim 2, wherein the cobalt oxalate powder is obtained by recycling the waste lithium cobalt oxide positive electrode powder through oxalic acid treatment, and the specific oxalic acid treatment comprises the steps of mixing the waste lithium cobalt oxide positive electrode powder with oxalic acid, and carrying out solid-liquid separation after the reaction is finished to obtain the cobalt oxalate powder.
  4. 4. The method of claim 3, wherein the specific conditions of the reaction are 60-80 ℃ and the reaction is 2-4 hours.
  5. 5. The method of claim 3, wherein the concentration of oxalic acid is 1mol/L.
  6. 6. The method of claim 5, wherein the solid-to-liquid ratio of the waste lithium cobalt oxide positive electrode powder to oxalic acid is 1 g/L-4 g/L.
  7. 7. Co 3 O 4 with vacancy defects prepared by the preparation method of any one of claims 1 to 6.
  8. 8. Use of Co 3 O 4 with vacancy defects according to claim 7 for the preparation of oxygen evolution electrocatalysts.
  9. 9. An oxygen evolution electrocatalyst comprising Co 3 O 4 with vacancy defects according to claim 7.

Description

Vacancy defect Co 3O4 and preparation method and application thereof Technical Field The application relates to the technical field of cobaltosic oxide preparation, in particular to a vacancy defect Co 3O4, a preparation method and application thereof. Background In recent years, with the development of global low-carbon economy, renewable energy sources are developed and used to replace traditional fossil energy sources, and the renewable energy sources have important strategic significance for sustainable development of human society. Among them, the preparation of "green hydrogen" by electrolysis of water is the most promising approach to develop renewable clean energy hydrogen. However, an important factor limiting the industrialization of electrolytic water technology is the large consumption of electrical energy required to drive the oxygen evolution reaction (Oxygen Evolution Reaction, OER) that occurs at the anode. The development of an OER catalyst with high efficiency and low cost to replace a commercial noble metal catalyst, and the reduction of the OER reaction energy barrier to improve the water electrolysis efficiency have important significance for realizing the industrialization of the water electrolysis technology. Based on the requirements of industrial production on the aspects of electrocatalyst activity, stability, cost and the like, the transition metal oxide Co 3O4 material is widely paid attention to by scientific researchers. However, the pure Co 3O4 material has the problems of poor conductivity, insufficient activity and the like, and is difficult to meet the practical requirements when being directly applied to the electrolytic water reaction. Defect engineering is often used as an effective modification means, can effectively adjust the surface composition, electronic structure, charge distribution and local environment around active sites of the electrocatalyst, and is widely used for improving the electrocatalytic oxygen evolution performance of a non-noble metal catalyst. The introduction of oxygen and metal vacancies has been demonstrated to optimize the adsorption behavior of the intermediates, accelerate surface charge transfer, and promote the construction of the surface active phase, thereby improving OER performance of the electrocatalyst. Currently, researchers can form oxygen vacancies in Co 3O4 materials by ion implantation, laser or plasma etching, chemical etching, gas reduction, and the like. The method has the defects of high requirements on instruments and equipment, complex subsequent treatment process, high cost and the like, and is not beneficial to large-scale preparation of the defect Co 3O4 material in practical application. Therefore, how to simply and conveniently mass-produce the vacancy-defect Co 3O4 material is still a research focus and difficulty in the field. Disclosure of Invention The application aims to provide a preparation method of improved vacancy defect Co 3O4, and application of the prepared vacancy defect Co 3O4 and the prepared vacancy defect Co 3O4. The application adopts the following technical scheme: The first aspect of the application discloses a preparation method of vacancy defect Co 3O4, which comprises the steps of calcining cobalt oxalate at a high temperature of 400-1000 ℃ for 0.5-4 h, and immediately placing the calcined cobalt oxalate in a cooling environment for rapid cooling after the high-temperature calcination is completed to obtain Co 3O4 with vacancy defects. It should be noted that the key point of the present application is that it is found that oxalic acid is decomposed under high temperature calcination to produce Co 3O4, and the Co 3O4 material in high temperature state is rapidly cooled, and the defects in the Co 3O4 crystal lattice structure are retained, so that Co 3O4 with vacancy defects is produced. When the obtained vacancy defect Co 3O4 is used as an oxygen evolution electrocatalyst, the water electrolysis efficiency can be improved, and the OER performance of the electrocatalyst can be improved. In one implementation of the application, the cooling environment is room temperature air, water or liquid nitrogen. It can be understood that the key point of the application is that the research discovers that Co 3O4 in a high temperature state can be rapidly cooled to generate Co 3O4 with vacancy defects, and the specific cooling environment can be room temperature air, room temperature water or liquid nitrogen, or other organic matter liquid with cooling function. Of course, in order to further realize faster cooling, cooling air or cooling water of 4-20 ℃ can be used. However, in one implementation of the present application, the vacancy defects Co 3O4 obtained by cooling with room temperature water are already satisfactory for use. In one implementation of the application, the cooling environment preferably employed is room temperature water. In one implementation of the application, the rapid cooling is pe