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

Abstract

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.