ニッケル-酸素軌道相互作用の調整による酸素活性化の制御と過酸化水素光合成の強化

Nickel-based co-catalysts are attractive candidates for H₂O₂ photosynthesis via the two-electron oxygen reduction reaction (2e^- ORR). However, inherently strong O₂ adsorption and overactivation at Ni sites promote undesired O-O bond cleavage, compromising both selectivity and activity. Here, we introduce an orbital-level modulation strategy that tailors O₂ activation at Ni centers by tuning the Ni 3d-O 2p interactions through atomic ligand regulation. Specifically, incorporation of electronegative phosphorus ligands into Ni-decorated poly(triazine imide) (Ni/PTI) reconfigures the Ni 3d orbital distribution, constructing Ni₂P/PTI that suppresses excessive O₂ activation and reverses the H₂O₂ decomposition observed in Ni/PTI. This strategy achieves a 4.7-fold enhancement in H₂O₂ production under visible light in pure water. Mechanistically, phosphorus-mediated electronic tuning diminishes Ni 3 d_yz orbital contributions to O₂ π* antibonding orbitals, thereby preventing O-O bond cleavage and stabilizing key intermediates. Concurrently, phosphorus-induced Ni coordination adjustment promotes *OOH protonation and inhibits H₂O₂ decomposition, jointly reinforcing 2e^- ORR selectivity and efficiency. These findings establish atomic ligand-driven orbital modulation as a powerful principle for steering O₂ activation on Ni-based co-catalysts, offering a blueprint for designing transition-metal sites with optimized electronic structures and coordination environments for efficient H₂O₂ photosynthesis.