Well controlled reduction, N-doping and cross-linking of graphene hydrogel: As good template for photocatalytic reaction

Abstract The combination of semiconductor nanoparticles (NPs) and graphene in the form of composite aerogels has become a valid strategy for improving the photocatalytic performance. However, the disorderly aggregation of NPs and the complexity of the synthesis process remain as great challenges limiting the applications. Herein, we put forward a graphene hydrogel template for convenient and accurate synthesis of three-dimensional ZnO/nitrogen-doped (N-doped) graphene aerogel by well regulating the reduction process of graphene oxide (GO) flakes based on thermodynamic analysis. The control-formed hydrogel template with moderate reduction degree retains adsorption sites for Zn2+, assuring the formation of well-distributed ZnO NPs on the three-dimensional N-doped graphene network. Owing to the synergistic effect between ZnO NPs and graphene network, the composite shows excellent photocatalytic performance under visible light. Besides, by pre-introducing common polymer fibers into the preparation system, big size composite aerogel could be easily produced, which ensures the facility for the large-scale practical applications.