Plasmonic Cu nanoparticle on reduced graphene oxide nanosheet support: An efficient photocatalyst for improvement of near-infrared photocatalytic H2 evolution

Cu nanoparticles (NPs) are low-cost plasmonic metals and have been used for photocatalytic hydrogen evolution due to their surface plasmon resonance (SPR) effect. An efficient photocatalyst consisting of plasmonic Cu NPs on reduced graphene oxide (rGO) nanosheets support (Cu/rGO) is successfully prepared by a facile in-situ photoreduction process to form multiple nanoscale junctions for enhancement of photocatalytic hydrogen evolution. Compared to individual Cu NPs, the coupling to rGO nanosheets produces a higher photocatalytic ability with the highest H-2 evolution rate of 59 mmol g(-1) h(-1) for sample C, which contains 1.0 wt% of rGO nanosheets. The rGO nanosheet possesses an extremely high conductivity and, can accept and transfer photo generated electrons with no barrier. Therefore, recombination of photoinduced charges can be efficiently suppressed and the accepted electrons can be rapidly transferred to reactive sites for H2 evolution across its two-dimensional plane. More importantly, a near-infrared photocatalytic activity for sample C was obtained under monochromatic light irradiation at 800 and 900 nm due to the broad spectrum response of plasmonic Cu NPs. Furthermore, a possible reaction mechanism is proposed for the photocatalytic activity improvement as well as the detailed charge transfer condition.