Photocatalytic Coupling of CH4 and CO2 to Ethanol on Asymmetric Ce−O−Zn Sites

Abstract Partial oxidation of methane (CH 4 ) to value‐added products is significantly challenging due to the highly inert chemical property of CH 4 at ambient conditions and easy over‐oxidation into carbon dioxide (CO 2 ) or carbon monoxide (CO) at elevated temperatures and pressures. Targeting this challenge, the efficient photocatalytic coupling of CO 2 and CH 4 into ethanol is demonstrated, using a cerium (Ce)‐doped zinc oxide (ZnO) photocatalyst with abundant Ce─O─Zn units. Under light illumination, CO 2 is adsorbed on the Ce atoms and photo‐reduced to CO, and CH 4 is captured by the Zn atoms and photo‐oxidized to hydroperoxymethane (CH 3 OOH). The close proximity of Ce and Zn atoms on the Ce─O─Zn units allowed to further efficiently couple the as‐formed CO and CH 3 OOH into ethanol. Without additional Oxygen (O 2 ) oxidant or sacrificial regent, the ethanol production rate reached 580 µmol g −1 h −1 , substantially exceeding previously reports on photocatalytic CH 4 oxidation. This work features to convert two greenhouse gases into value‐added chemicals with adjacent and asymmetric reaction sites, suggesting attractive potentials for CH 4 and CO 2 utilization.