(228d) Atom Trapping: A Novel Approach to Generate Thermally Stable and Regenerable Single Atom Catalysts
An important goal of heterogeneous catalyst synthesis is dispersion of the active metal uniformly on a catalyst support, ideally achieving atomic dispersion. Isolated single atoms dispersed on oxide supports (single-atom catalysts) provide efficient utilization of scarce platinum group metals and have attracted a lot of interest because of improved atom efficiency, higher reactivity and better selectivity for a range of catalytic reactions. Synthesis methods for depositing transition metals, through strong electrostatic adsorption (SEA), ion exchange, co-precipitation, grafting, impregnation or deposition-precipitation are well developed. To generate single-atom catalysts using these currently available methods, it is necessary to use low metal loading, and to limit the operating temperatures to prevent agglomeration of single atoms into nanoparticles. However, for industrial applications, it would be desirable to achieve high metal loadings and stable performance at high temperatures. Here we show that ceria possesses the unique ability to trap isolated single atoms, providing high thermal stability. Metal loadings of 3 wt% can be easily achieved while maintaining exclusively single atoms.