Photochemical and Photoelectrochemical Reduction of CO2

The recent literature on photochemical and photoelectrochemical reductions of CO2 is reviewed. The different methods of achieving light absorption, electron-hole separation, and electrochemical reduction of CO2 are considered. Energy gap matching for reduction of CO2 to different products, including CO, formic acid, and methanol, is used to identify the most promising systems. Different approaches to lowering overpotentials and achieving high chemical selectivities by employing catalysts are described and compared.