Preparation method for doped graphene foams

Abstract

The invention discloses a preparation method for doped graphene foams. The preparation method comprises the following steps: adopting the hydrothermal method to enable nano particles to dope with and generate on oxidized graphene sheets to obtain oxidized graphene aerogel; reducing the oxidized graphene aerogel doped with the nano particles in a controllable manner at the low-temperature gaseous phase condition to obtain the doped graphene foams. According to the preparation method, a reductant is not used in the growing process of the nano particles, and liquid is not introduced into the reaction system, so that excessive overlap of the graphene layers is avoided, porosity of the graphene foams is maintained, polyporous shrinkage caused by surface stress is prevented, and the uniformly doped graphene foam material with the controllable appearance is obtained. The preparation method is convenient to operate, uniform in doping, controllable in product size, economical and fast, is adopted as the novel technology for the large-scale preparation of the doped graphene foam material, and is expected to provide novel materials for graphene adsorbents, graphene capacitors, graphene catalysts and the like.

Description

technical field [0001] The invention belongs to the technical field of preparation of modified graphene foams, in particular to a method for preparing nanoparticle-doped porous graphene foams with controllable size through low-temperature reduction. Background technique [0002] Graphene foam is a three-dimensional interconnected porous structure formed by staggered stacking of graphene sheets, which can effectively avoid excessive stacking of conventional graphene sheets, so graphene foam well maintains the single layer (or few layers) of graphene. The structure and corresponding properties have the characteristics of a large specific surface area, good conductivity and adsorption properties, and are widely used in supercapacitors, biosensing, conductive composite materials, catalysis, sewage treatment and other fields, and are the most potential applications. One of the nanomaterials. Doping graphene foam is an important means to further improve the performance of graphen...

AI Technical Summary

Problems solved by technology

Among them, the hydrothermal reduction method and the high-temperature gas phase reduction method can be used to make doped graphene foam, but because these two methods have their own defects, which restrict their large-scale practical application.

Just comprise as the defective of hydrothermal reduction method: 1) graphene sheet is because the effect of liquid surface tension easily overstacks, thereby makes the pore structure of graphene foam can collapse and shrink, causes the shrinkage ratio of usual product to be greater than 50%, makes final The size of the product cannot be controlled

2) Since the dopant and reducing agent coexist in the same system, the growth of nanoparticles and the reduction of graphene oxide sheets are carried out simultaneously, which easily leads to uneven doping

3) Due to the severe reduction reaction under hydrothermal conditions, it is difficult to effectively control the reduction degree of graphene foam (Ren, L.; Hui, K.S.; Hui, K.N. Self-assembled free-standing three-dimensional nickel nanoparticle / graphene aerogel for direct ethanol fuel cells.J.Mater.Chem.A2013,1,5689-5694.)

However, the high-temperature gas-phase method has harsh reaction conditions, requires the use of inert gas or reducing gas in the reaction process, high reaction temperature, high equipment requirements and high production costs (Liu, F; Seo, T.S.A controllable self-assembly method for large-scale synthesis of graphene sponges and free-standing graphene films. Adv. Funct. Mater. 2010, 20, 1930-1936.)

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