Aerogels for sustainable CO2 electroreduction to value-added chemicals

Carbon dioxide electrochemical reduction (CO2ER) affords an appealing pathway for transforming discarded CO2 to fuels and economic chemicals. Various nanocatalysts have been used for CO2ER, of which porous catalysts have attracted widespread attentions because of their large electrochemically active surface area, large number of pores for molecule transportation, and high local pH. Aerogels (including carbon-based aerogels and metallic aerogels), as a new class of porous catalysts, have been applied to CO2ER in recent years because of their high electrical conductivity (to reduce overpotential), three-dimensional porous structure and intrinsic hydrophobicity (to inhibit parasitic hydrogen evolution reaction, HER). In this article, we reviewed latest progresses toward aerogels for CO2ER, including (1) synthesis strategies of carbon-based aerogels and metallic aerogels; (2) innovations in aerogels design, such as heteroatom doping and metal incorporation in carbon-based aerogel, creating grain boundaries, regulating Cu0-Cu+ interfaces, and optimizing synergistic effect in metal aerogels; and (3) structural properties of aerogel catalysts to enhance CO2ER performance. Finally, we discuss the challenges, possible solutions and future directions for further development of aerogels in CO2ER.