Resolving the puzzle of single-atom silver dispersion on nanosized \u03b3-Al2O3 surface for high catalytic performance

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

doi:10.1038/s41467-019-13937-1

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.

Highlights

Ag/γ-Al2O3 is widely used for catalyzing various reactions, and its performance depends on the valence state, morphology and dispersion of Ag species
We find that the presence of abundant terminal hydroxyl groups on the nanosized γ-Al2O3 leads to the single-atom dispersion of Ag species on the γ-Al2O3 surface
These results indicate that 1% Ag can be atomically dispersed on nano-Al2O3, whereas the Ag species agglomerates into nanoparticles on micro-Al2O3

Summary

Introduction

Ag/γ-Al2O3 is widely used for catalyzing various reactions, and its performance depends on the valence state, morphology and dispersion of Ag species. We find that the presence of abundant terminal hydroxyl groups on the nanosized γ-Al2O3 leads to the single-atom dispersion of Ag species on the γ-Al2O3 surface. These results indicate that 1% Ag can be atomically dispersed on nano-Al2O3, whereas the Ag species agglomerates into nanoparticles on micro-Al2O3.

Results

Conclusion