Boosting C2+production from photoelectrochemical CO2 reduction on gallium doped Cu2O

Photoelectrochemical CO2 reduction into C2+ products not only realizes the efficient conversion and utilization of CO2, but also provides a new way to synthesize value added hydrocarbons. However, it remains a grand challenge for highly selective synthesis of C2+ product due to the complexity of CO2 reduction and the coexis-tence of competitive reaction on the electrode surface. Herein we report a gallium doped Cu2O catalyst (Ga/ Cu2O) 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 CO2 reduction into C2+ products with Faradaic efficiencies of C2+, CH3CH2OH, and CH3CH2CH2OH as high as 20%, 6.5% and 6.64%, respectively at the potential of-1.8 V vs reversible hydrogen electrode (RHE). Experi-mental results show that Ga doping generated more oxygen vacancies via partial substitution in the lattice of Cu2O, resulting in rapid separation of the generated electron-hole pairs and regulating the electronic structure of catalyst surface and promotion of CO2 adsorption and activation. As a result, a higher *CO coverage and better C-C coupling probability on the surface of Ga/Cu2O were reached compared to those of unmodified Cu2O, which are responsible for the enhancement of the selectivity of CO2RR into C2+ products.

Automated summary

We report a gallium-doped Cu2O catalyst (Ga/ Cu2O) prepared by electrochemical deposition on a Cu mesh, which exhibits high efficiency and selectivity in reducing CO2 to C2+ products. The catalyst achieves Faradaic efficiencies of 20% for C2+, 6.5% for CH3CH2OH, and 6.64% for CH3CH2CH2OH at a potential of -1.8 V vs reversible hydrogen electrode (RHE). Ga doping generates oxygen vacancies and regulates the catalyst surface's electronic structure, resulting in enhanced CO2 adsorption and activation, and promoting the selectivity of CO2 reduction into C2+ products.