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 KNO 3 and graphene support, producing K 2 O at 400 °C. Further increasing the temperature to 800 °C, the graphene reduces K 2 O to K anchored by its vacancies, leading to the generation of K SAs (denoted as K 1 /G). The source of basicity in the K 1 /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 K 1 /G shows excellent catalytic activity and stability in transesterification reaction, which is much superior to the reported catalysts.