Plasmon-Enhanced Photocatalytic Properties of Cu2O Nanowire-Au Nanoparticle Assemblies

Cu2O-Au nanocomposites (NCs) with tunable coverage of Au were prepared by a facile method of mixing gold nanoparticles (Au NPs) with copper(I) oxide nanowires (Cu2O NWs) in various ratios. These Cu2O-Au NCs display tunable optical properties, and their photocatalytic properties were dependent on the coverage density of Au NPs. The photocatalytic activity of Cu2O-Au NCs was examined by photodegradation of methylene blue. The presence of Au NPs enhanced the photodegradation efficiency of Cu2O NCs. The photocatalytic efficiency of Cu2O-Au NCs initially increased with the increasing coverage density of Au NPs and then decreased as the surface of Cu2O became densely covered by Au NPs. The enhanced photocatalytic efficiency was ascribed to enhanced light absorption (by the surface plasmon resonance) and the electron sink effect of the Au NPs.