Pivotal Impact Factors in Photocatalytic Reduction of CO2 to Value‐Added C1 and C2 Products

Over the past decades, CO 2 greenhouse emission has been considerably increased, causing global warming and climate change. Indeed, converting CO 2 into valuable chemicals and fuels is a desired option to resolve issues caused by its continuous emission into the atmosphere. Nevertheless, CO 2 conversion has been hampered by the ultrahigh dissociation energy of C=O bonds, which makes it thermodynamically and kinetically challenging. From this prospect, photocatalytic approaches appear promising for CO 2 reduction in terms of their efficiency compared to other traditional technologies. Thus, many efforts have been made in the designing of photocatalysts with asymmetric sites and oxygen vacancies, which can break the charge distribution balance of CO 2 molecule, reduce hydrogenation energy barrier and accelerate CO 2 conversion into chemicals and fuels. Here, we review the recent advances in CO 2 hydrogenation to C 1 and C 2 products utilizing photocatalysis processes. We also pin down the key factors or parameters influencing the generation of C 2 products during CO 2 hydrogenation. In addition, the current status of CO 2 reduction is summarized, projecting the future direction for CO 2 conversion by photocatalysis processes.