Resolving the puzzle of single-atom silver dispersion on nanosized ?-Al2O3 surface for high catalytic performance.

ABSTRACT: Ag/?-Al2O3 is widely used for catalyzing various reactions, and its performance depends on the valence state, morphology and dispersion of Ag species. However, detailed anchoring mechanism of Ag species on ?-Al2O3 remains largely unknown. Herein, we reveal that the terminal hydroxyls on ?-Al2O3 are responsible for anchoring Ag species. The abundant terminal hydroxyls existed on nanosized ?-Al2O3 can lead to single-atom silver dispersion, thereby resulting in markedly enhanced performance than the Ag cluster on microsized ?-Al2O3. Density-functional-theory calculations confirm that Ag atom is mainly anchored by the terminal hydroxyls on (100) surface, forming a staple-like local structure with each Ag atom bonded with two or three terminal hydroxyls. Our finding resolves the puzzle on why the single-atom silver dispersion can be spontaneously achieved only on nanosized ?-Al2O3, but not on microsized ?-Al2O3. The obtained insight into the Ag species dispersion will benefit future design of more efficient supported Ag catalysts.

SUBMITTER: Wang F 

PROVIDER: S-EPMC6985108 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature