Multishelled hollow CaTiO3 cubes decorated with Co0.2Cd0.8S nanoparticles for efficient photocatalytic H2 evolution via S-scheme charge transfer

Rationally designing S-scheme heterostructures with boosted charge separation efficiency and superior redox ability is regarded as an appealing strategy to conquer the shortcomings of mono-component and conventional heterojunction photocatalysts. Herein, a novel hierarchical S-scheme heterostructured photocatalyst was constructed by integrating Co0.2Cd0.8S nanoparticles on multishelled hollow CaTiO3 cubes to substantially improve the photocatalytic hydrogen production activity. An internal electric field (IEF) is formed at the heterojunction interfaces owing to the significant disparity in Fermi level (EF) between Co0.2Cd0.8S and CaTiO3, accompanied by the energy band bending, which enables the S-scheme charge transport route in the Co0.2Cd0.8S/CaTiO3 heterostructure, as verified by electron paramagnetic resonance and theoretical calculations. Benefiting from the boosted separation efficiency and superior redox capability of photocarriers within the constructed S-scheme heterostructure, the optimized Co0.2Cd0.8S/CaTiO3 sample exhibited a significantly improved photocatalytic hydrogen evolution rate of 8.13 mmol h−1 g−1, far exceeding that of mono-component counterparts and previously reported Co0.2Cd0.8S- or CaTiO3-based photocatalysts. This study is anticipated to inspire the strategic development of other economical and efficient S-scheme photocatalytic systems with enhanced H2 evolution activity.