ZnWO4/BiOI heterostructures with highly efficient visible light photocatalytic activity: the case of interface lattice and energy level match

Abstract

ZnWO₄/BiOI heterostructures with different constituents are synthesized via a chemical bath approach under mild conditions by tuning the Zn/Bi molar ratios. The obtained ZnWO₄/BiOI heterostructures display high photocatalytic activities in degradation of MO and photocurrent response under visible light irradiation. Combining the experimental findings, first-principles calculations are used to investigate the surface geometry structures and the work functions of the (011) and (010) surfaces of the ZnWO₄ phase and the (001) surface of the BiOI phase. The results show that the lattice and energy levels between the ZnWO₄ and BiOI phases match well with each other to be capable of forming efficient ZnWO₄/BiOI p–n heterojunction structures. This match promotes the separation and transfer of photoinduced electron–hole pairs at the interface, resulting in the excellent photocatalytic performance of the ZnWO₄/BiOI heterostructures. Our findings show that the formation of a heterostructure would possess the excellent photocatalytic activities only if the lattice and energy level match between the two semiconductors was satisfied, which is of great importance for designing and developing more efficient heterostructured photocatalysts.