Asymmetric Pt₁C₃-Pt₁O₁C₃ catalytic pairs for efficient transfer hydrogenation of azobenzene

Atomic catalytic pairs (CPs) have shown great promise in driving multi-step catalytic transformations, yet the influence of spatial arrangement and coordination asymmetry on homonuclear CPs remain poorly understood. Herein, we construct atomically dispersed homonuclear Pt₁-Pt₁ CPs with asymmetric Pt₁C₃-Pt₁O₁C₃ coordination anchored on reduced graphene oxide. By precisely tuning the spacing between the adjacent Pt₁C₃-Pt₁O₁C₃ CPs to approximately 5.3 Å, the catalyst achieves an exceptional turnover frequency of 27,218 h^-1 for transfer hydrogenation of azobenzene via ammonia-borane hydrolysis, surpassing benchmarking catalysts by more than an order of magnitude. The Pt₁C₃-Pt₁O₁C₃ CPs separated by 5.3 Å can facilitate co-adsorption of sterically hindered intermediates and at the same time the asymmetric Pt₁C₃-Pt₁O₁C₃ coordination enables facile hydrogen shuttling and barrier-suppressed hydrogenation. These synergistic effects enhance the overall azobenzene hydrogenation efficiency. Our findings uncover a fundamental spatial design principle for atomically precise homonuclear asymmetric CPs, offering new opportunities for sustainable and efficient fine chemical synthesis.