Line defects in plasmatic hollow copper ball boost excellent photocatalytic reaction with pure water under ultra-low CO concentration.

By using a low CO concentration as a C1 source, the design of a plasmonic catalyst that can effectively photocatalytic CO reduction is of great significance for sustainable and ecological development. Herein, the space confinement effect and liquid environment of the molten salt result in uniform hollow structure, while the strong aggressive force furnished via using molten salt enhances the formation of line defects. This special structure can not only provide a large number of active sites but also greatly accelerate the transport of photoinduced charge carriers. The hollow copper ball with line defects (CCu) shows excellent photocatalytic activity with pure water (1028.57 μmol g), and it also shows good catalytic activity even under ultra-low CO content, which far exceeds the catalytic activity of most semiconductor-based catalysts. This work is designed to simultaneously construct line defect and hollow structure in plasmatic metal nanoparticles for efficient photocatalytic CO reduction.