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

Over the past decades, CO₂ greenhouse emission has been considerably increased, causing global warming and climate change. Indeed, converting CO₂ into valuable chemicals and fuels is a desired option to resolve issues caused by its continuous emission into the atmosphere. Nevertheless, CO₂ 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 CO₂ 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 CO₂ molecule, reduce hydrogenation energy barrier and accelerate CO₂ conversion into chemicals and fuels. Here, we review the recent advances in CO₂ hydrogenation to C₁ and C₂ products utilizing photocatalysis processes. We also pin down the key factors or parameters influencing the generation of C₂ products during CO₂ hydrogenation. In addition, the current status of CO₂ reduction is summarized, projecting the future direction for CO₂ conversion by photocatalysis processes.