C–Doping Induced Oxygen-Vacancy in WO3 Nanosheets for CO2 Activation and Photoreduction

Sluggish charge kinetics and low CO2 affinity seriously limit the photocatalytic CO2 reduction reaction. Herein, the simultaneous promotion of charge transfer and CO2 activation over two-dimensional (2D) WO3 nanosheets is achieved by coupling surface C-doping and oxygen vacancy. The surface-doped C atoms reconstruct the atomic surface of WO3 by extracting oxygen lattice to generate the intimate oxygen vacancy (C–OV coordination) as the active center, which facilitates the CO2 adsorption/activation, thus inducing the formation *CO2 species. As a charge delivery channel, an exclusive W–O–C covalent bond formed by C–OV coordination could enhance the electron transfer. As a result, the as-designed catalyst exhibits 85.8% selectivity for CO2 photoreduction to CO under the gas–solid phase reaction, with a yield rate of 23.2 μmol g–1 h–1 and a stable long-term reactivity over 24 h. Moreover, the in situ DRIFTS and DFT results reveal that this specific C–OV coordination enables the spontaneous CO2 activation and proton-coupled electron transfer to guarantee the sustained formation of *COOH and, thus, smooth the photocatalytic CO2 reduction reaction. This work develops a feasible strategy for electronic structure modification of photocatalysts with doping-induced oxygen vacancy to boost CO2 activation and photoreduction.