Elsevier

Journal of Catalysis

Volume 388, August 2020, Pages 84-90
Journal of Catalysis

Unveiling the gas-dependent sintering behavior of Au-TiO2 catalysts via environmental transmission electron microscopy

https://doi.org/10.1016/j.jcat.2020.05.003Get rights and content

Highlights

  • A gas-dependent sintering behavior of Au-TiO2 catalyst was visualized by in situ TEM.

  • Distinct sintering behaviors were observed under CO, O2 and CO/O2 mixed atmospheres.

  • The mechanisms were revealed through Cs-corrected STEM study.

Abstract

Gas-involved sintering of supported nanoparticles is a common process of catalysts deactivation, but the mechanism is still ambiguous. Herein, we investigated the sintering behaviors of a Au-TiO2-(1 0 1) model catalyst in different gas environments via in situ environmental transmission electron microscopy (ETEM), spherical aberration (Cs-) corrected scanning transmission electron microscopy (STEM) and ex situ annealing experiments. Distinct sintering behaviors of Au-TiO2 catalysts were observed in ETEM that O2 or O2/CO mixed atmospheres facilitated but CO inhibited the sintering process. Ex situ annealing experiments were in accordance with in situ results. Further study with Cs-corrected STEM showed that TiO2 support annealed in CO got rougher and more defective than that annealed in O2, which suppressed the free movement of Au particles on TiO2 surface.

Keywords

Catalyst sintering
Environmental transmission electron microscopy (ETEM)
Gas-dependent
In situ TEM, Au-TiO2 catalysts

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1

These authors contributed to this work equally.

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