Atomic-Termination-Engineered Multi-Orbital Coupling for CO₂- Assisted Photocatalytic CH₄ Oxidation

Carbon dioxide (CO₂)-assisted CH₄ photo-oxidation is a promising strategy for promoting the carbon cycle, yet it remains highly challenging due to inefficient charge separation and the limited active reaction sites. Regulating the terminal layers of semiconductors provides an effective strategy for tailoring surface active sites and tuning the electronic structure. Herein, we modulate the p-d orbital hybridization in Bi₂MoO₆ via atomic-termination engineering, tailoring surface states to facilitate charge carrier transfer and molecular activation. The p-p hybridization between Bi-6p and O-2p orbitals induced by [Bi₂O₂]²⁺ termination generates shallow surface states, enabling more efficient transport of charge carriers from the bulk to the surface. Meanwhile, the favorable orbital coupling between Bi-6p and C-2p orbitals at the interface between [Bi₂O₂]²⁺ termination and CO₂ promotes CO₂ activation by lowering the energy of its antibonding orbitals. As a result, the BO-BMO and MO-BMO photocatalysts achieve CO evolution rates of 285.36 and 93.32 µmol g⁻¹ h⁻¹, respectively, under simulated solar light irradiation. This work demonstrates efficient CH₄ conversion using CO₂ as a soft oxidant through atomic-scale termination control to engineer two distinct orbital-coupling pathways. These findings provide a new theoretical foundation and experimental paradigm for the rational design of surface terminations and the optimization of catalytic reactions.