Unlocking solar energy: Photocatalysts design for tuning the CO2 conversion into high-value (C2+) solar fuels

The carbon dioxide (CO2) conversion to useful chemicals is a promising technique to address global environmental issues and ensure a renewable energy supply. Despite the efforts to enhance product yield with different catalysts, most studies focused on improving efficiency with less emphasis on the selectivity of higher hydrocarbon (C2+) products. Hence, CO, CH4, and HCOOH are the commonly obtained products during CO2 photoreduction according to most literature. C2+ hydrocarbons have a higher market value compared to C1 products. Therefore, research on photocatalytic CO2-to-C2+ conversion has received significant attention in recent years. This review discusses the progress of CO2-to-C2+ photoconversions. First, the insights into CO2 reduction, kinetics, critical challenges, and underlying mechanisms involved in the conversion of CO2-to-C2+ are highlighted. Further, the progress on strategies such as defect engineering, heteroatom doping, cocatalysts deposition, single or dual-atom catalysts, heterostructured combinations, and morphological modulations to improve the selectivity of CO2 reduction towards C2+ formation has been discussed. Factors affecting the performance of CO2-toC2+ are discussed throughout, focusing on aspects like the interaction of reactants with the catalyst surface, various reaction conditions, intermediate formation, *C1 stabilization, and C-C coupling. Finally, a summary and outlook on recent trends in CO2 utilization are discussed.