Visible-light driven CO2 reduction coupled with water oxidation on Cl-doped Cu2O nanorods

Abstract Visible-light driven overall conversion of CO 2 and H 2 O into chemical fuels and O 2 is a challenging but promising reaction for artificial photosynthesis. Here we demonstrate Cl-doped Cu 2 O nanorods for photocatalytic CO 2 reduction conjugated with H 2 O oxidation under visible-light irradiation. Cl-doping optimizes the band structure of Cu 2 O, resulting in a more positive valence-band position for H 2 O oxidation, and promotes CO 2 adsorption capacity as well as separation and transfer efficiency of photogenerated charge carriers. Consequently, the Cl-doped Cu 2 O shows excellent photocatalytic CO 2 reduction performance accompanied by favorable H 2 O oxidation ability under visible-light irradiation. The best sample achieves an apparent quantum efficiency of 2.2% with 1.13% for CO and 1.07% for CH 4 at 400 nm and demonstrates superior stability. Density functional theory calculations further reveal that Cl-doped Cu 2 O is beneficial for the transformation of CO 2 into the intermediates of *COOH, *CO, and *CH 3 O, which contributes to the enhanced activity of CO and CH 4 production. Additionally, Cl-doped Cu 2 O shows stronger affinity toward the *CO intermediate, which tends to be protonated and ultimately transforms into CH 4 , leading to higher selectivity of CH 4 than that of pure Cu 2 O. This work validates an effective strategy to engineer Cu 2 O for visible-light driven overall conversion of CO 2 reduction and H 2 O oxidation.