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.