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

• Published in: Nature communications 2020-01, Vol.11 (1), p.1-9, Article 529
• Main Authors: Wang, Fei, Ma, Jinzhu, Xin, Shaohui, Wang, Qiang, Xu, Jun, Zhang, Changbin, He, Hong, Cheng Zeng, Xiao
• Format: Article
• Language: English
• Subjects: 140/131; 142/136; 639/638/542/971; 639/638/77/885; 639/638/77/887; Aluminum oxide; Anchoring; Atoms & subatomic particles; Catalysts; Catalytic oxidation; Chemical reactions; Dispersion; Humanities and Social Sciences; Laboratories; Metals; Morphology; multidisciplinary; Nanoparticles; Performance enhancement; Science; Science (multidisciplinary); Silver; Species; Transitional aluminas; Valence
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-13937-1

Ag/γ-Al 2 O 3 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 γ-Al 2 O 3 remains largely unknown. Herein, we reveal that the terminal hydroxyls on γ-Al 2 O 3 are responsible for anchoring Ag species. The abundant terminal hydroxyls existed on nanosized γ-Al 2 O 3 can lead to single-atom silver dispersion, thereby resulting in markedly enhanced performance than the Ag cluster on microsized γ-Al 2 O 3 . 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 γ-Al 2 O 3 , but not on microsized γ-Al 2 O 3 . The obtained insight into the Ag species dispersion will benefit future design of more efficient supported Ag catalysts. Detailed atom-level anchoring mechanism of Ag species on γ-Al 2 O 3 is largely unknown for the widely used Ag/γ-Al 2 O 3 catalyst. Here, the authors demonstrate that single-Ag atom can be only anchored by the terminal hydroxyls on the (100) surfaces of γ-Al 2 O 3 through consuming two or three terminal hydroxyls.