Design of advanced aerogel structures for oxygen reduction reaction electrocatalysis

Abstract Oxygen reduction reaction (ORR) is considered the bottleneck reaction in fuel cells. Its sluggish kinetics requires the use of scarce and expensive platinum group metal (PGM) catalysts. Significant efforts have been invested in trying to find a PGM‐free catalyst to replace Pt for this reaction or reduce its loadings. One interesting family of materials that has shown great promise in doing so is aerogels, which are based on covalent frameworks. The aerogels’ high surface area and porosity enable good mass transport and high catalyst utilization that is expected to lower PGM loadings or replacing them completely. This review summarizes recent research in this field, introducing methods of using aerogels as cathodes for ORR, from carbon to metal aerogels. The catalytic sites vary from nanoparticles to atomically dispersed metal ions embedded in carbon aerogels that form all‐in‐one platform which can serve as both the support and the catalyst.