A Review of Metal- and Metal-Oxide-Based Heterogeneous Catalysts for Electroreduction of Carbon Dioxide

Capping and, eventually, reducing the atmospheric levels of greenhouse gases such as CO₂ is an urgent priority, and a focus of multidisciplinary efforts. Among other techniques, advanced technologies for CO₂ capture and conversion are highly desirable to limit CO₂ emissions. Electrochemical reduction of CO₂, using off-peak renewable electricity, to value-added chemicals and fuels has attracted extensive research interest. A main effort is directed toward the development of efficient, selective, and robust electrocatalysts to promote CO₂ reduction, due to its sluggish reaction kinetics. Here, recent investigations and achievements in the design of metal- and metal-oxide-based heterogeneous catalysts are reviewed in terms of catalytic activity, selectivity, stability, and mechanism. A classification of heterogeneous CO₂ catalysts is presented based on the main products of electrochemical reduction of CO₂, including HCOOH, CO, C₂H₄, CH₃OH, and C₃H₈O. The key catalysts' properties favoring the production of specific chemical products from the CO₂ reduction reaction are critically discussed. The challenges for achieving superior CO₂ reduction electrocatalysts are discussed providing future research directions for their design and development.