Boosting C2+ production from photoelectrochemical CO2 reduction on gallium doped Cu2O
Xiuling Guo, Cong Wang, Zihao Yang, Yong Yang
Abstract
Photoelectrochemical CO 2 reduction into C 2+ products not only realizes the efficient conversion and utilization of CO 2 , but also provides a new way to synthesize value added hydrocarbons. However, it remains a grand challenge for highly selective synthesis of C 2+ product due to the complexity of CO 2 reduction and the coexistence of competitive reaction on the electrode surface. Herein we report a gallium doped Cu 2 O catalyst (Ga/Cu 2 O) prepared by a typical electrochemical deposition method via oriented growth on the surface of Cu mesh with easily controllable Ga contents. As the self-supporting electrode, it exhibits a highly efficient and selective CO 2 reduction into C 2+ products with Faradaic efficiencies of C 2+ , CH 3 CH 2 OH, and CH 3 CH 2 CH 2 OH as high as 20%, 6.5% and 6.64%, respectively at the potential of −1.8 V vs reversible hydrogen electrode (RHE). Experimental results show that Ga doping generated more oxygen vacancies via partial substitution in the lattice of Cu 2 O, resulting in rapid separation of the generated electron-hole pairs and regulating the electronic structure of catalyst surface and promotion of CO 2 adsorption and activation. As a result, a higher *CO coverage and better C-C coupling probability on the surface of Ga/Cu 2 O were reached compared to those of unmodified Cu 2 O, which are responsible for the enhancement of the selectivity of CO 2 RR into C 2+ products.