Ni doping-induced oxygen vacancies promote electron transfer in Bi2MoO6 for efficient photocatalytic CO2-to-CH4 conversion

Photocatalytic CO 2 reduction into value-added fuels is an appealing route to store solar energy while mitigating carbon emissions, yet achieving efficient and highly selective hydrocarbon formation in pure water remains challenging. Herein, we report a dopant co-engineering strategy by constructing Ni-doped Bi 2 MoO 6 with abundant oxygen vacancies (Ni x BMO-O V ). An ethylene glycol-mediated synthesis enables vacancy-rich Bi O environments and exposes abundant active sites, thereby strengthening CO 2 adsorption and accelerating interfacial charge transfer to facilitate hydrogenation toward CH 4 . Under simulated solar irradiation using pure H 2 O as the sole proton source, the optimized Ni 0.15 BMO delivers a CH 4 evolution rate of 45.0 μmol·g −1 ·h −1 with an exceptional CH 4 selectivity of 99.1%. Ni incorporation and O V modulate the local electronic structure and charge distribution, thereby affecting the adsorption and activation of CO 2 and intermediates toward the target CH 4 product. This work provides an effective synergistic strategy involving Ni incorporation and oxygen vacancies for regulating electronic structure and reaction pathways toward efficient photocatalytic CO 2 reduction.