▎ 摘　　要

NOVELTY - Preparing graphene-silica aerogel comprises e.g. (i) preparing brown sheet-shaped graphite oxide, (ii) preparing graphene oxide solution, (iii) preparing graphene by dissolving ethylenediamine in deionized water in a beaker, magnetically stirring, dropwise adding graphene oxide solution, stirring, and sealing the mixed solution in an oven to obtain black colloid, (iv) preparing silica sol, (v) preparing chitosan solution, (vi) preparing graphene-silica mixed sol, and (vi) preparing graphene-silica aerogel: cooling the gel in a low temperature refrigerator, drying in a freeze dryer, and drying. USE - The method is useful for preparing graphene-silica aerogel (claimed). ADVANTAGE - The method: maintains good heat-temperature thermal insulation property and mechanical property of the aerogel under low temperature condition; improves the single silica gel brittle performance; is simple and economical; has strong operability; and yields silica airgel having low density. DETAILED DESCRIPTION - Preparing graphene-silica aerogel comprises (i) preparing graphite oxide: adding concentrated sulfuric acid in a reaction container, then placing in ice water bath, adding natural graphite of sodium nitrate, ultrasonically stirring, slowly adding potassium permanganate into the reaction container, continuously stirring, transferring the reaction container to another water bath, raising temperature to 25-45 degrees C, slowly adding distilled water into the reaction container, and then transferring the reaction container to a high temperature oil bath, continuously stirring, adding distilled water and 10-40% hydrogen peroxide to obtain bright yellow mixture, washing the resultant mixture with 1-10% hydrochloric acid and distilled water until it is neutral, and vacuum drying in a vacuum drying box at 50-100 degrees C for 12-24 hours to obtain brown sheet-shaped graphite oxide, (ii) preparing graphene oxide solution: taking graphite oxide obtained in the step (i), dissolving in deionized water, performing ultrasonic dispersion for more than 30 minutes, and centrifuging and separating out un-stripped graphite oxide and impurities to obtain fulvous uniform graphene oxide solution, (iii) preparing the graphene: dissolving ethylenediamine in deionized water in a beaker, magnetically stirring for specific time, dropwise adding graphene oxide solution, stirring, and sealing the mixed solution in an oven to obtain black colloid as reduced graphene oxide, (iv) preparing silica sol: taking silicon source, water and ethanol in a container, magnetically stirring, adjusting pH to 2-5 using hydrochloric acid, stirring and allowing to stand, and adjusting pH to 6-7 using N,N-dimethyl formamide and aqueous ammonia to obtain viscous silica sol, (v) preparing chitosan solution: taking acetic acid solution and deionized water to prepare acetic acid solution, and dissolving chitosan by stirring in acetic acid solution to obtain chitosan solution, (vi) preparing graphene-silica mixed sol: mixing reduced graphene oxide, silica sol and chitosan solution, magnetically stirring to obtain the mixed sol, keeping stirring, dropping N,N-dimethyl formamide and aqueous ammonia, and allowing to stand till the gel forms, and (vi) preparing graphene-silica aerogel: cooling the resultant gel in a low temperature refrigerator, drying in a freeze dryer for 24-48 hours, and drying in a vacuum oven to obtain graphene-silica aerogel.