Two Different\nAtomically Dispersed Pt Atoms Supported\non Ceria

Atomically dispersed metals on oxide supports with different\ndistribution\npositions or coordination environments can dictate the reactivity;\nthey have therefore attracted tremendous attention recently. Nonetheless,\nthe acknowledging and understanding of different single atoms remain\nchallenging due to the reactivity controversy of the supported single\natoms and clusters or nanoparticles, particularly on the widely used\nceria supports. Herein, by modulating the loading amount of Pt single\natoms carefully with strong electrostatic adsorption on conventionally\nsynthesized ceria supports, we obtained two different atomically dispersed\nPt atoms with similar Pt–O coordination environments and CO\nadsorption characteristics. One is anchored on the surface of ceria,\nand it can migrate and aggregate once activated with reduction–reoxidation\ntreatments. The other may be trapped by the surface defects or vacancies\nin ceria and would be fixed on the ceria support firmly in isolated\nstates during activation. Despite the similar CO adsorption during\nthe reaction, the former can catalyze CO oxidation in both the status\nof single atoms and aggregated PtO<sub><i>x</i></sub> clusters.\nHowever, the latter is inactive for the reaction and would not be\naffected by the activation treatment. It cannot involve the CO oxidation,\nresulting in the waste of supported Pt atoms.