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

Fei Wang; Jinzhu Ma; Shaohui Xin; Qiang Wang; Jun Xu; Changbin Zhang; Hong He; Xiao Cheng Zeng

doi:10.1038/s41467-019-13937-1

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

Nat Commun. 2020 Jan 27;11(1):529. doi: 10.1038/s41467-019-13937-1.

Authors

Fei Wang^#^{1

2}, Jinzhu Ma^#^{1

2

3}, Shaohui Xin^{2

4}, Qiang Wang⁴, Jun Xu⁴, Changbin Zhang^{5

6}, Hong He^{1

2

3}, Xiao Cheng Zeng⁷

Affiliations

¹ State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
² University of Chinese Academy of Sciences, Beijing, 100049, China.
³ Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
⁴ State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China.
⁵ State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China. cbzhang@rcees.ac.cn.
⁶ University of Chinese Academy of Sciences, Beijing, 100049, China. cbzhang@rcees.ac.cn.
⁷ Department of Chemistry, Department of Chemical & Biomolecular Engineering, and Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA. xzeng1@unl.edu.

^# Contributed equally.

Abstract

Ag/γ-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 γ-Al₂O₃ remains largely unknown. Herein, we reveal that the terminal hydroxyls on γ-Al₂O₃ are responsible for anchoring Ag species. The abundant terminal hydroxyls existed on nanosized γ-Al₂O₃ can lead to single-atom silver dispersion, thereby resulting in markedly enhanced performance than the Ag cluster on microsized γ-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 γ-Al₂O₃, but not on microsized γ-Al₂O₃. The obtained insight into the Ag species dispersion will benefit future design of more efficient supported Ag catalysts.