1D-2D Z-scheme junction by coupling CaTiO3 rectangular nanorods with CdS nanosheets enhances photocatalytic hydrogen evolution

Abstract

Designing and developing Z-scheme photocatalytic system for highly efficient hydrogen production through water splitting is a prospective strategy to alleviate energy and environmental issues. Herein, CaTiO₃/CdS nanocomposites have been synthesized by a simple solvothermal method, in which CaTiO₃ and CdS present rectangular nanorods and nanosheet-like morphologies, respectively. The optimized 60%-CaTiO₃/CdS composite exhibits a remarkable photocatalytic performance with H₂ evolution rate of ∼12,381.80 μmol·g^-1·h^-1, and it is 1.9 and 124 times higher than that of single CdS and CaTiO₃, respectively. Photoluminescence (PL), photocurrent, and electrochemical impedance measurements confirm boosted interfacial charge separation within CaTiO₃/CdS photocatalyst. Notably, as verified by the band structures, XPS analysis and fluorescence probe experiments, the intimate Z-scheme heterojunction interface constructed between two components plays a critical role in promoting the separation of photogenerated e^-/h⁺ pairs and retaining superior redox capabilities, thus leading to enhanced H₂ evolution performance. Moreover, this synthetic method could be applied to other MTiO₃ (M = Sr and Ni) type semiconductors in accelerating the photocatalytic H₂ production. It is anticipated this work could offer a reference for rationally designing and constructing perovskite-based composite catalysts with improved solar-to-hydrogen conversion.