Efficient nanomaterials for harvesting clean fuels from electrochemical and photoelectrochemical CO2 reduction

The excessive utilization of fossil fuels accompanied by large amounts of anthropogenic CO2 emissions have led to adverse global environmental changes and a growing global energy crisis. Hence, converting CO2 into high-value chemical fuels, such as CO, CH4, HCOOH, and CH3OH, through catalysis is one of the most attractive topics in energy conversion. Among various approaches, electrochemical (EC) and photoelectrochemical (PEC) reduction are considered to be promising methods. Over the past decades, research in the area of CO2 EC and PEC reduction has been growing quickly. Herein, highly efficient nanostructured metals, metal alloys, metal oxides, metal-free electrodes, and photoelectrodes developed in recent years are discussed in detail in this review. Additionally, the strategies and mechanisms for improving the faradaic efficiency (FE), current density, and stability of catalysts are also discussed. The challenges and future perspectives for CO2 EC and PEC reduction are also discussed.