d-p band coupling accelerates photocatalytic hydrogen evolution rate of metal and non-metal single atom co-modified TiO2.

Metal-support interactions (MSI) have recently emerged as a pivotal structural factor in boosting photocatalytic hydrogen evolution (HER) by optimizing charge separation and transfer. Here, we integrate DFT + U, ab initio molecular dynamics (AIMD), and experiments to explore the HER mechanistic pathways of 112 metal single-atom configurations (MA = Fe, Co, Ni, Cu, Pd, Pt, Ag, Au) on C, N-modified TiO2. MSI can finely promote charge transfer and adsorption-desorption kinetics, lowering the d-band center of MA sites toward the Fermi level and shifting the p-band center of O site negatively, thereby improving carrier separation. Explicit solvation modeling of mixed methanol reveals that the Volmer-Heyrovsky step is an optimal pathway for HER (barrier: 0.5 eV). Additionally, extended X-ray absorption fine structure (EXAFS) confirms Pt in 0.6 % Pt/TCN (TCN is C, N co-doped TiO2) exhibits a coordination number of 3.19, matching the Pt bridge-loaded configuration. Remarkably, 0.6 % Pt/TCN achieves a carrier lifetime of 3.29 ns and HER rate of 9.31 mmol g-1 h-1, outperforming other configurations. This work elucidates atomic-level MSI mechanisms, thus opening new avenues toward the design of high-efficiency HER photocatalysts.