Au@SnO2 Core@Shell Nanocrystals for Sustainable Environmental Purifications

Abstract

The search for versatile catalysts for sustainable environmental purifications has been a challenging yet very important research topic especially in the post pandemic era. Core@shell nanocrystals composed of metal core and semiconductor shell have received significant attention as both photocatalysts and chemical catalysts for practical use in organic dyes degradation and bacterial disinfection. This work reports the synthesis of Au@SnO2 core@shell nanocrystals with controllable shell thicknesses. Under light illumination, Au@SnO2 can function as photocatalysts to decompose organic dyes (rhodamine B, RhB) and inactivate E. coli. Because of the band alignment between Au and SnO2, an enhanced photocatalytic activity was achieved on Au@SnO2. Time-resolved photoluminescence spectroscopic analysis was conducted to explore the influence of shell thickness on the interfacial charge dynamics of Au@SnO2 in order to establish the correlation with the resultant photocatalytic performance. On the other hand, the peroxidase mimics features of Au and SnO2 endowed Au@SnO2 with the capability of performing the disinfection of E. coli under darkness conditions. By combining the phtotocatalytic capacity with the peroxidase mimics features, Au@SnO2 demonstrated sustainable activity toward E. coli disinfection under both irradiation and darkness conditions.