Preparation method of nanometer cobalt oxide/graphene composite material

Abstract

The invention discloses a preparation method of a nanometer cobalt oxide / graphene composite material. A surface active agent is dissolved into water, graphite is added, after 10 to 50 hours of ultrasonography, the rotational speed is controlled to be 4000 to 5000 r / min and the centrifugation is performed for 10 to 30 min, cobalt salt is added into an obtained supernatant fluid, stirring is unceasingly performed for 20 to 30 min, and a solution A is obtained; a urea water solution with the concentration of 1-5 mol / L is dripped into a solution A, then the temperature is controlled to be 90 to 180 DEG C for reaction for 5 to 15 hours, an obtained reacting liquid is naturally cooled to be at the room temperature and then centrifugation is performed, after washing, precipitates are treated through vacuum drying, then under the protection of inert gas, and the temperature is risen at a speed of 1 DEG C / min and under the protection of inert gas to be 400 to 500 DEG C for calcination for 3 to 5 hours, that is, the nanometer cobalt oxide / graphene composite material is obtained. According to the preparation method provided by the invention, the reaction conditions are mild, oxidation of a strong oxidant is not used, the prepared graphene is less in defects, and the catalytic performance is improved greatly.

Description

technical field [0001] The invention relates to a preparation method of a nanometer cobalt trioxide / graphene composite material, which belongs to the field of material technology. Background technique [0002] Cobalt tetroxide (Co 3 o 4 ) is an important magnetic material and P-type semiconductor, which is widely used in anode materials of lithium-ion batteries, solar energy absorbing materials, solid-state sensors, heterogeneous catalysis, electrochromic devices and dyes, etc. co 3 o 4 Has a spinel structure, the Co in its structure 3+ The octahedron and Co 2+ The tetrahedrons of are surrounded by oxygen atoms respectively, which have high crystal field stabilization energy. co 3 o 4 It is a black or blue-purple cubic crystal powder. Although it is easy to absorb water after long-term exposure to the air, it is not easy to form hydrates with water. When the heating temperature is lower than 800 ° C, Co 3 o 4 Very stable, when heated to 900 °C, Co 3 o 4 will deco...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the above-mentioned cobalt tetroxide / graphene composite material preparation process that contains a lot of oxygen-containing functional groups on the graphene and cannot be completely removed. In view of technical problems such as the catalytic performance of ene composites, a method for preparing nano-cobalt trioxide / graphene composites is provided. The biggest feature of this preparation method is that it uses liquid phase exfoliation to directly exfoliate graphite to prepare graphene, which avoids oxidation and reduction. A large number of oxygen-containing functional groups introduced by the process cannot be completely removed, which affects the electrochemical performance of the composite material; at the same time, the method uses a surfactant-assisted method to synthesize nano-cobalt trioxide / graphene composite materials in one step, which has the characteristics of simple process

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