Single-atom loaded BTEA-COF for enhanced visible-light photocatalytic H₂ production: insights from first-principles...

In this study, we employed the first-principles and real-time time-dependent density functional theory (rt-TDDFT) calculations to investigate the mechanism of visible-light-driven photocatalytic H₂ production on transition-metal loaded BTEA-COF. Among 11 metallic elements screened, Pt is identified as the optimal modifier. Pt loading significantly improves the photocatalytic performance by (1) reducing the Gibbs free energy of hydrogen by 38% to 0.19 eV, (2) extending the optical absorption edge from 441 nm (2.81 eV) to 576 nm (2.15 eV) via metal-to-ligand charge transfer, and (3) enhancing the density of photogenerated electrons and suppressing the recombination of charge carriers. Rt-TDDFT simulations of the H₂O@Pt/BTEA-COF interface reveal the femtosecond-scale dynamics of water photolysis. The process is dominated by electron transfer from the Pt/BTEA-COF system to the adsorbed water molecule, facilitating O-H bond cleavage at ∼30 fs. The Pt atom acts as a dual-function charge pump, mediating both electron and hole transfer. These findings provide fundamental insights into the superior activity of single-atom catalysts and establish design principles for developing high-efficiency COF-based photocatalytic systems.