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

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-V_S) is synthesized by a one-step solvothermal method. When there are sulfur vacancies in the Bi₂S₃ lattice (Bi₂S₃-V_S), 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.