Au@Cu₂O core@shell nanocrystals as dual-functional catalysts for sustainable environmental applications

This work reports the synthesis of Au@Cu₂O core@shell nanocrystals with controllable shell thicknesses and demonstrates their use as the dual-functional catalyst that can continuously operate under illumination and darkness conditions for efficient E. coli inactivation. On account of the peroxidase mimics of the Au core and Fenton reactivity of the Cu₂O shell, the Au@Cu₂O nanocrystals exhibit intrinsic peroxidase-like property with the reaction kinetics in accordance with the typical Michaelis–Menten mechanism. On the other hand, time-resolved photoluminescence spectra suggest the prevalence of pronounced charge separation for Au@Cu₂O nanocrystals, an important advantage that is favourable for photocatalysis. By combining the photocatalytic capability with the peroxidase mimics features, Au@Cu₂O nanocrystals can perform practical photocatalytic decomposition of E. coli under visible light illumination but still show vital activity towards E. coli inactivation after light illumination was turned off. The current study delivers a new catalyst configuration by exploiting the multiple functionalities of nanosized Au and Cu₂O for advanced environmental and energy conversion applications.