Graphene oxide as the passivation layer for Cu_xO photocatalyst on a plasmonic Au film and the corresponding photoluminescence study

The contribution of graphene oxide (GO) on photocatalytic effects of Cu_xO on plasmonic Au is investigated. It is found that the H₂ evolution rate from pure water is enhanced 1.4 fold using the visible-active Cu_xO/GO photocatalyst, as compared with Cu_xO without GO. In addition, the intensity of photoluminescence of Cu_xO/GO can be enhanced as much as 2.85 fold as compared with Cu_xO without GO. The enhancement is due to the negative fixed charge in GO, which can passivate the surface of Cu_xO and suppress recombination of minority electrons at the surface. The results from optical characterization in this study can help to prove the proposed mechanism of passivation.