Ultrastable Au nanoparticles on titania through an encapsulation strategy under oxidative atmosphere

Shaofeng Liu,Lirong Zheng,Junhu Wang,Bingsen Zhang,Wei Xu,Wei Liu,Lin Li,Yiming Niu

doi:10.1038/s41467-019-13755-5

Abstract

Supported gold catalysts play a crucial role in the chemical industry; however, their poor on-stream stability because of the sintering of the gold nanoparticles restricts their practical application. The strong metal-support interaction (SMSI), an important concept in heterogeneous catalysis, may be applied to construct the structure of catalysts and, hence, improve their reactivity and stability. Here we report an ultrastable Au nanocatalyst after calcination at 800 °C, in which Au nanoparticles are encapsulated by a permeable TiOx thin layer induced by melamine under oxidative atmosphere. Owning to the formed TiOx overlayer, the resulting Au catalyst is resistant to sintering and exhibits excellent activity and stability for catalytic CO oxidation. Furthermore, this special strategy can be extended to colloidal Au nanoparticles supported on TiO2 and commercial gold catalyst denoted as RR2Ti, providing a universal way to engineer and develop highly stable supported Au catalysts with tunable activity.

Highlights

Supported gold catalysts play a crucial role in the chemical industry; their poor onstream stability because of the sintering of the gold nanoparticles restricts their practical application
We demonstrate that Au NPs can be encapsulated by a permeable TiOx overlayer under oxidative atmosphere induced by melamine, the reverse of condition required for classical strong metal-support interaction (SMSI) between Au and TiO228
No melamine was observed on the surface of Au NPs, which was different from the previous work (Fig. 1b and Supplementary Fig. 1b)[23]

Summary

Introduction

Supported gold catalysts play a crucial role in the chemical industry; their poor onstream stability because of the sintering of the gold nanoparticles restricts their practical application. SMSI has been exploited to enhance catalytic performance of the catalysts by modifying the electronic and geometric factors of the metal NPs27,40–48 For long ages it has been well-recognized that Au cannot manifest SMSI, which was ascribed to its low work function and surface energy and its low ability to dissociate H2 to active the support in the previous investigation[49,50,51,52]. Under this assumption, a few successes have been achieved that an oxide overlayer can be formed on gold supported on ZnO, hydroxyapatite and phosphate supports in oxygen atmosphere, contrary to the condition required for classical SMSI27,53,54.

Methods

Results

Conclusion