Characteristics of graphene oxide doped silica aerogels
In order to meet the needs of high temperature protection,rapid preparation of aerogels with high strength and low thermal conductivity has become an important scientific challenge.The performance of silica aerogels prepared by supercritical drying method was successfully improved by doping graphene oxide(GO).It was observed by electron microscope that GO was evenly embedded in the gel matrix,forming an effective support framework,and significantly enhancing the strength of the gel.Fourier transform infrared spectroscopy analysis showed that there was only physical binding between GO and silica aerogel,and no obvious chemical bond was formed.The nitrogen adsorption/desorption measurements show that the specific area and pore size of GO/SiO2 aerogels can be controlable by adjusting the GO amount.When the content of GO is 0.5％,1％and 2％by mass,the specific surface areas of GO/SiO2 aerogels are 895 m2/g,1294 m2/g and 997 m2/g,respectively,which is higher than that of undoped silica aerogels(852 m2/g).Due to the addition of GO,the density of GO/SiO2 aerogel(0.07 g/cm3)is slightly higher than that of pure SiO2 aerogel(0.06 g/cm3),providing it with higher strength and bearing capacity.In addition,the thermal conductivity of these doped aerogels is 0.0176-0.0204 W/(m·K),which is lower than that of pure SiO2 aerogels(0.0221 W/(m·K)).This result provides a new idea and method for the promotion and application of SiO2 aerogel in practical applications.
graphene oxidedopingsilica aerogelsupercritical dryingthermal conductivityspecific surface area
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