Facet-dependent interfacial charge separation and transfer in plasmonic photocatalysts

Abstract

Surface plasmon resonance (SPR) induced plasmonic photocatalysis provides a brand new way for more efficient light absorption and utilization to achieve better solar light conversion. Although the SPR effect in metal-semiconductor photocatalysis has been widely investigated, the SPR-driven interfacial charge separation and transfer patterns between the two counterparts have not yet been fully revealed. The plasmonic metal-semiconductor photocatalytic systems require to be rationally designed, especially for the facet-aspect of the semiconductor, which can dominantly endow the contacting interface with diverse charge transfer patterns. Taken Bi metal deposited at the typical (001) and (010) facets of BiOBr nanosheets as a case study, we demonstrate that the surface charge alternation on the (010) facet highly favors the interfacial charge separation and transfer, by providing a new route of [Bi2O2]2+ → plasmonic metal → Br− for interfacial carriers transfer. The charge alternation on discrepant semiconductor facets in essence makes the plasmonic photocatalytic system be different in charge transportation pattern. These new findings are further validated in extensive composite systems composed of alternative plasmonic metal (Ag and Au) and semiconductors (BiOCl and BiOI). The perspective here can open numerous possibilities for the rational design of more efficient plasmonic photocatalysts.