Inorganic-organic CdS/YBTPy S-scheme photocatalyst for efficient hydrogen production and its mechanism

S-scheme heterojunctions have garnered significant attention for efficient photocatalytic H₂ evolution due to their superior charge separation and maximized redox potential. In this study, we developed a novel pyrene-benzothiadiazole conjugated polymer (YBTPy) through Yamamoto coupling, followed by the in situ deposition of CdS nanoparticles via a solvothermal method to construct a CdS/YBTPy S-scheme heterojunction photocatalyst. The optimized composite, designated as CP5, demonstrated a hydrogen production rate of 5.01 mmol h⁻¹ g⁻¹, representing a 4.2-fold enhancement compared to pristine CdS (1.20 mmol h⁻¹ g⁻¹). The characteristic S-scheme charge transfer pathway at the heterojunction interface was elucidated using in situ irradiated X-ray photoelectron spectroscopy in conjunction with Kelvin probe force microscopy. Additionally, femtosecond transient absorption spectroscopy was employed to investigate the dynamics of photogenerated charge carriers. This work provides a new theoretical foundation for the design of organic–inorganic hybrid S-scheme photocatalytic systems.