Photocatalytic Performance of 3D Ni/Graphene/ZnO Composites Fabricated by Hydrothermal Processing

ZnO nanorods are fabricated by the hydrothermal processing on the 3 dimensional (3D) Ni/Chemical Vapor Deposition (CVD) grown multilayer graphene and 3D Ni foams, respectively, and their photocatalytic performance are investigated. It is found that the composites with the graphene sandwiched between the 3D Ni and ZnO nanorods with 4 hours hydrothermal growth exhibits superior photocatalytic performance toward methyl orange (MO) under simulated sunlight, whose apparent degradation rate constant is about 1.3 times larger compared to that without graphene incorporated. Meanwhile, the underlying substrates show tremendous influence on the morphology and structures of ZnO nanorods, which imposes vital influence on the composites photocatalytic performance. The sparsely distributed and well crystalized ZnO flower-like nanorods with the enhanced content ratio of (002) plane on the 3D Ni/graphene foam reveal optimal performance, which can be attributed to the hybrid effect of the effective separation of the photo-generated electron-hole pairs due to the easy transferring of charges at graphene/ZnO interface through secure graphene/ZnO contacts, and the enhanced photocatalytic reduction of well crystallized and (002) enriched ZnO nanorods. The mechanism responsible for the enhancement of the photocatalytic degradation and the formation of the distinguished morphology and structure of ZnO nanorods are discussed in details.