Subnano-FeOx Clusters Anchored in an Ultrathin Amorphous Al2O3 Nanosheet for Styrene Epoxidation

The development of low-cost, high-performance catalysts at the atomic level has drawn scientists' attention due to the high atom efficiency, unique structure, and potentially high catalytic selectivity. Among the atomically tailored catalysts, nanoclusters are of particular interest because they represent an underexplored medium state between isolated single atoms and typical nanoparticles. In this study, we report a wet-chemistry approach to synthesize highly dispersed subnano-FeOx clusters anchored on an ultrathin amorphous Al2O3 nanosheet (or Al2O3–FeOx nanosheet) and its excellent catalytic performance for selective conversion of styrene to styrene oxide. The reasons for the high catalytic performance of the Al2O3–FeOx nanosheet are 2-fold. One is that the unsaturated and amorphous nature of the Fe atoms in the subnano-FeOx clusters promotes the adsorption of styrene onto the catalytic sites of FeOx clusters for epoxidation. The other is that the amorphous Al2O3 nanosheet prevents the aggregation of catalytic FeOx clusters during the epoxidation reaction because its defective structure immobilizes the FeOx clusters.