Alkali-assisted hydrothermal preparation of g-C3N4/rGO nanocomposites with highly enhanced photocatalytic NOx removal activity

Abstract Graphitic carbon nitride / reduced graphene oxide (g-C3N4/rGO) nanocomposites have become research hotspots owing to its excellent charge carrier separation efficiency and enhanced photocatalytic activity. Herein, we developed a facile alkali-assisted hydrothermal strategy to prepare g-C3N4/rGO nanocomposites. In the hydrothermal process, the NaOH not only played an important role in etching the bulk g-C3N4 into nanosheets to increase its specific surface area and active sites, but also promoted the reduction of GO to enhance the conductivity of rGO. The rGO sheets could act as an excellent electron acceptor and electronic conductive channels to improve the separation efficiency of photogenerated electron-hole pairs. The resultant g-C3N4/rGO nanocomposites exhibited 2.7 times higher photocatalytic NOx removal activity than that of bulk g-C3N4 due to the enlarged specific surface area and the enhanced separation efficiency of photogenerated carriers. Moreover, the obtained metal-free photocatalyst displayed outstanding photocatalytic performance under visible light irradiation (λ˃400nm), compared with previously reported traditional-metal-based semiconductor photocatalysts. This work may provide new insights into preparing g-C3N4/rGO nanocomposites with enhanced photocatalytic activity.