A kind of preparation method of ultra-high specific surface area carbon aerogel material

Abstract

The invention discloses a preparation method of a carbon aerogel material with ultra-high specific surface area. The method comprises four steps: wet ball milling of biomass fibers, TEMPO oxidation of the ball-milled biomass fibers, preparation of oxidized biomass fiber aerogels, Pyrolytic carbonization. The cellulose carbon aerogel prepared by the invention has a unique three-dimensional sheet-like stacking structure, which provides great potential for its application as a material such as a catalyst, an adsorbent and an electrode capacitor.

Description

technical field [0001] The invention relates to a preparation method of a gel material, in particular to a preparation method of a carbon aerogel material with an ultra-high specific surface area. Background technique [0002] Carbon aerogel is a new type of lightweight, porous, three-dimensional network-like amorphous carbonaceous material with a large specific surface area (400-1000 m 2 / g), low density, nanoscale continuous pores and amorphous structure. Such materials were first synthesized from resorcinol and formaldehyde by sol-gel method and further prepared by high temperature carbonization. At present, common carbon aerogel raw materials mainly include resorcinol and formaldehyde, melamine and formaldehyde, phenolic resin and furfural, linear polymer N-methylol acrylamide and resorcinol, etc., and the above precursors are large Some of them are more toxic compounds, which have certain environmental and health risks to the natural environment and researchers. [0...

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Problems solved by technology

This preparation process uses an organic solvent as the reaction medium, the reaction temperature is high, the steps are complicated, and it takes a long time

Zhang Tao of Jiangsu University and others used the cellulose in agricultural waste such as corn husks and cotton straw husks to obtain cellulose extracts after being washed with relatively simple ethanol and deionized water, and then treated with lye, and then bleached with acetic acid and sodium hypochlorite. 1. After washing and purifying, freeze-dry for 35 hours, and finally carbonize in a tube furnace to obtain the corresponding cellulose carbon airgel. Although this method is relatively simple, the agricultural waste particles in the preparation process are large, and the bleaching and lye treatment are not uniform, so it is difficult to Ensure the chemical properties and structural homogeneity of the final product carbon airgel, and its maximum surface area is only 675.8m 2 / g

Lu Yun of the Chinese Academy of Forestry Sciences also used the TEPMPO oxidation method to modify cellulose nanocrystals, but the degree of oxidation was not high, and the specific surface area of ​​the prepared carbon airgel was still relatively small, and the degree of porosity was low. The pretreatment and oxidation degree of cellulose nanocrystals may be the main limiting steps; at the same time, the higher price of cellulose nanocrystals makes the final carbon aerogel more costly

[0007] Therefore, the use of biomass fiber materials to prepare carbon aerogels has the characteristics of strong environmental friendliness, mild reaction conditions, low cost, and superior performance in catalysis, energy storage, and adsorption. The method of preparing carbon airgel from material fibers is relatively scarce

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