Catalytically Stable Potassium Single-Atom Solid Superbases

Solid superbases can catalyze diverse reactions under mild conditions, while they suffer from aggregation of basic sites and poor stability during recycling. Here we report a new generation of solid superbases derived from K single atoms (SAs) prepared by a tandem redox strategy. The initial redox reaction takes place between base precursor KNO₃ and graphene support, producing K₂O at 400 °C. Further increasing the temperature to 800 °C, the graphene reduces K₂O to K anchored by its vacancies, leading to the generation of K SAs (denoted as K₁/G). The source of basicity in the K₁/G is K SAs, and neighboring single atoms (NSAs) possess superbasicity, which is different from conventional basicity originated from oxygen and nitrogen atoms. Due to the superbasicity as well as high dispersion and anchoring of basic sites, the K₁/G shows excellent catalytic activity and stability in transesterification reaction, which is much superior to the reported catalysts.