An anthraquinone-integrated S-scheme-based NiTiO₃-g-C₃N₄ composite with enhanced hydrogen production activity

A novel anthraquinone (AQ) integrated and S-scheme-based NiTiO₃-gC₃N₄ (NT-gCN) photocatalytic system is synthesized with an improved electron transfer rate for hydrogen production. Materials characterization using spectroscopic techniques reveal the intimate heterojunction interface between NT and gCN as well as integration of AQ with the binary composite. The synthesized AQ-NT-gCN photocatalyst exhibits a significantly enhanced H₂ evolution rate (576 μmol g⁻¹ h⁻¹), which is ∼22 and 33% higher than that of NT-gCN and gCN, respectively, attributed to the spatial separation of charge carriers expedited by AQ. The radical trapping test data provide evidence for the S-scheme charge transfer mechanism in AQ-NT-gCN. The present study opens a new avenue for developing an S-scheme heterojunction by integrating binary composite with an organic molecule to improve the solar to energy conversion efficiency.