Role of interfacial oxygen vacancies in low-loaded Au-based catalysts for the low-temperature reverse water gas shift reaction

Gold-based catalysts have shown high catalytic activity for reverse water gas shift (RWGS) reactions at low temperatures. Despite extensive studies, the RWGS reaction on Au-based catalysts with very low Au content (< 0.1 wt%) has not yet been investigated. In this study, TiO2 and ZrO2 supported g...

Full description

Saved in:
Bibliographic Details
Published in:Applied catalysis. B, Environmental Environmental, 2023-02, Vol.321, p.122083, Article 122083
Main Authors: Rabee, Abdallah.I. M., Zhao, Dan, Cisneros, Sebastian, Kreyenschulte, Carsten R., Kondratenko, Vita, Bartling, Stephan, Kubis, Christoph, Kondratenko, Evgenii V., Brückner, Angelika, Rabeah, Jabor
Format: Article
Language:English
Subjects:
CO2 hydrogenation
Gold
Operando spectroscopy
Oxygen vacancy
Reverse water–gas shift
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Gold-based catalysts have shown high catalytic activity for reverse water gas shift (RWGS) reactions at low temperatures. Despite extensive studies, the RWGS reaction on Au-based catalysts with very low Au content (< 0.1 wt%) has not yet been investigated. In this study, TiO2 and ZrO2 supported gold catalysts with such low gold loading have been synthesized and tested for RWGS. The catalysts were investigated by a series of in/ex-situ characterization techniques, including ICP-OES, XRD, BET, XPS, STEM, STEM-EELS, TAP, in-situ DRIFTS and in-situ EPR. At 250 oC, the Au/TiO2 catalyst showed almost 10 times higher activity than Au/ZrO2. In-situ DRIFTS results suggest that the formate mechanism is the predominant mechanism over Au/ZrO2, while over Au/TiO2 the reaction proceeds via the formation of hydroxycarbonyl intermediates. A combined study including STEM, STEM-EELS, XPS, and in-situ EPR suggests that the interfacial Au–Ov–Ti3+ sites are responsible for the superior activity of Au/TiO2. [Display omitted] •Au/TiO2 exhibited superior activity and CO selectivity.•Ti3+formation and oxygen vacancies on Au/TiO2 contribute to its superior activity.•The weak adsorption strength of CO is responsible for the superior CO selectivity.•An Oxygen-vacancies-engaged reaction mechanism is proposed for RWGS over Au/ZrO2.•The decomposition of formate seems to be the rate-limiting step in the CO formation.
ISSN:0926-3373
1873-3883
DOI:10.1016/j.apcatb.2022.122083