Peroxidase-Enhanced Photocatalytic Activity of Au-Cu2O Core-Shell Nanocrystals

Abstract

As the talented motif of two-component systems, core-shell nanocrystals with multi-functional chemical properties have attracted ever-increasing interests. Among the different material combinations, Au-based core-shell nanocrystals are particularly appealing since the protected, nano-sized Au can perform a myriad of catalytic reactions, e.g. peroxidase enzyme mimics. On the other hand, utilization of Au can benefit semiconductor nanostructures for various photocatalytic applications. The introduced Au may function as charge separation enhancer for semiconductor, which improves the carrier utilization efficiency to promote photocatalysis. In this work, Au-Cu2O core-shell nanocrystals were synthesized and used for unique peroxidase-assisted photocatalytic applications. By virtue of the peroxidase-like property of nano-sized Au, Au-Cu2O can catalyze hydrogen peroxide to generate OH radicals for participation in photocatalytic reactions. On the other hand, due to the relative band alignment, introduction of Au can enhance the charge separation of Cu2O, therefore improving the overall photocatalytic activity. The peroxidase-enhanced photocatalytic properties of Au-Cu2O nanocrystals were evaluated by using methyl orange as the test pollutant. The results showed that Au-Cu2O surpassed pure Au and pure Cu2O in methyl orange degradation under light illumination. This superiority was ascribed to the functionality synergy between the remarkable peroxidase activity of Au and the pronounced charge separation of Au-Cu2O. This work delivers a new photocatalyst configuration by exploiting the multi-functionalities of nanosized Au for environmental and energy science applications.