Facet engineering on the interface of BiOCl-PbS heterostructures for enhanced broad-spectrum photocatalytic H2 production

The construction of semiconductor heterostructure photocatalysts is a promising strategy to extend the light absorption region and promote the electron-hole separation for improved solar-to-chemical energy conversion efficiency. The photocatalytic activity of the heterostructure is greatly determined by the efficiency of interfacial charge transfer. In this work, we demonstrate the facet engineered interface design of BiOCl-PbS photocatalytic structures. The PbS nanocrystals are selectively deposited on the (0 0 1) and (1 1 0) facets of BiOCl nanoplates to form BiOCl(0 0 1)-PbS and BiOCl(1 1 0)-PbS, respectively. It is found that the average H-2 production rate of BiOCl(1 1 0)-PbS photocatalyst is 2.5 times higher than that of BiOCl(0 0 1)-PbS under broad-spectrum irradiation. This enhancement is mainly ascribed to the different interfacial charge transfer efficiencies. Owing to the different band energies between BiOCl(0 0 1) and (1 1 0) facets, a V-shaped band alignment is formed in the BiOCl(0 0 1)-PbS sample, which results in the accumulation of photogenerated electrons in BiOCl(0 0 1)-PbS interface and prevents the further charge transfer and separation between BiOCl and PbS, while a ladder-shaped band alignment of BiOCl(1 1 0)-PbS achieves the smooth charge transfer and high-efficient charge separation without electron accumulation in the BiOCl(1 1 0)-PbS interface. This work represents a step toward the interface design of high-performance hybrid photocatalyst through facet engineering.