In situ photodeposition of Rh cluster loaded Cu-modified TiO₂ for enhancing hydrogen evolution from alcohol photoreforming

This study presents the rational design of RhCu-TiO₂ nano heterostructures for efficient solar-driven hydrogen production via alcohol photoreforming. Through sol-gel synthesis and in situ photodeposition, ternary catalysts featuring atomic Rh clusters (0.5 mol%) on local p–n nano-heterojunctions within Cu-modified TiO₂ were engineered. The optimized RhCu-TiO₂ exhibits a high hydrogen evolution rate of 28.73 mmol g⁻¹ h⁻¹ under UV light, representing 21.4-fold and 1.96-fold improvements over pristine TiO₂ and Cu-TiO₂, respectively. In situ DRIFTS analysis uncovers critical surface processes: alcohol molecules preferentially adsorb in bridged configurations, with Rh sites accelerating C–H bond activation through enhanced charge separation. Mott-Schottky analysis confirms a 6.4-folds increase in carrier density compared to TiO₂, while VB-XPS reveals progressive bandgap narrowing (3.07 → 1.75 eV) through Cu/Rh synergy. The catalyst exhibits robust stability (over 88% retention after 4 cycles) and substrate versatility. Mechanistic studies suggest that the Cu₂O-TiO₂ p-n heterojunction, coupled with Rh-mediated electron transfer, are key factors in suppressing charge recombination. This work systematically investigated the alcohol hydrogen production performance of ternary catalysts, revealing that the performance of multi-component catalysts designed through heterostructure construction and atomic-level co-catalyst dispersion is superior. Additionally, this study provides valuable insights into the underlying photocatalytic mechanisms, contributing to the advancement of photocatalyst design for hydrogen production applications.