Vacancy-induced tensile strain of CdS/Bi2S3 as a highly performance and robust photocatalyst for hydrogen evolution

Abstract

Lattice strain is a new strategy for promoting photocatalytic activity in order to source more sustainable energy. Vacancy-induced strain is an effective tactic for lattice deformation. Herein, a CdS/Bi2S3 heterojunction structure containing sulfur vacancies (CdS/Bi2S3-VS) is synthesized by a one-step solvothermal method. When there are sulfur vacancies in the Bi2S3 lattice (Bi2S3-VS), the surrounding atoms move toward sulfur vacancies. This phenomenon lengthens the bonds between surrounding atoms, resulting in tensile stress. Strain engineering adjusts the energy band structure to reduce the interface barrier height, thus effectively improving the interface charge transfer rate. Moreover, density functional theory (DFT) calculations explore the influence of different strain levels on the band structure and Gibbs free energy. The strain-regulated band structure provides a new approach and effectively reduce the interface barrier.