N杂化石墨烯气凝胶的组成和热导率

Composition and thermal conductivity of N-doped graphene aerogel

通过对苯二胺还原和CO_2超临界干燥制备N杂化石墨烯气凝胶。采用X线光电子能谱仪(XPS)、场发射扫描电子显微镜(FESEM)、N_2吸附仪和热常数分析仪表征样品在1 000℃裂解前后的微观结构、组成和热导率变化。结果表明:裂解后N杂化石墨烯气凝胶孔径增大,石墨烯上的杂化原子部分去除,常压和低压(5 Pa)热导率分别由0.031和0.014 W/(m·K)增大到0.057和0.019 W/(m·K)。裂解后气态热导是N杂化石墨烯气凝胶传热的主要方式。

N-doped graphene aerogel with paraphenylene diamine as reducing agent was prepared by CO_2 supercritical drying. The differences among microstructure,composition and thermal conductivity of Ndoped graphene aerogel with and without pyrolysis at 1 000 ℃ were investigated by X-ray photoelectron spectroscopy（ XPS）,filed emission scanning electron microscopy（ FESEM）,N_2 adsorption analyzer,and hotdisk apparatus. Results showed that with pyrolysis the pore size became larger. With N atoms getting into the graphene,some doped atoms were removed from graphene. During pyrolysis,the thermal conductivity at atmospheric pressure and that at 5 Pa increased from 0. 031 and 0. 014 W /（ m · K） to0. 057 and 0. 019 W /（ m · K）,respectively. The gaseous thermal conductivity of N-doped graphene aerogel with pyrolysis accounted for the greater part of the total thermal conductivity.