Copper promotion of chromium-doped iron oxide water-gas shift catalysts under industrially relevant conditions

Journal article (2022)

Authors

M.I. Ariëns RST/Fundamental Aspects of Materials and Energy - AS , Eindhoven University of Technology
L. G.A. van de Water Johnson Matthey Technology Center
A.I. Dugulan RST/Fundamental Aspects of Materials and Energy - AS , RID/TS/Instrumenten groep
E.H. Brück RST/Fundamental Aspects of Materials and Energy - AS
Emiel J.M. Hensen Eindhoven University of Technology
Research Group
RST/Fundamental Aspects of Materials and Energy (AS) (TU Delft)
Copyright: © 2022 M.I. Ariëns, L. G.A. van de Water, A.I. Dugulan, E.H. Brück, E. J.M. Hensen
DOI: https://doi.org/10.1016/j.jcat.2021.12.013
More Info
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Published Date

2022

Language

English

Faculty

Applied Sciences

Department

RST/Radiation, Science and Technology

Research Group

RST/Fundamental Aspects of Materials and Energy

Abstract

Copper promotion of chromium-doped iron oxide prepared via co-precipitation for high-temperature water–gas shift (WGS) catalysis is investigated. Low-temperature Mössbauer spectra demonstrate that copper doping delays hematite (α-Fe2O3) formation in the fresh catalyst, favoring the formation of small crystallites of ferrihydrite (Fe5HO8∙4 H2O). Catalysts are treated under industrial WGS conditions at 360 °C (activity evaluation) and 450 °C (ageing) at 2 and 25 bar. Mössbauer spectra show that chromium is incorporated in octahedral sites of the active magnetite (Fe3O4) phase, resulting in a partially oxidized structure. Copper doping did not affect the bulk magnetite structure of the activated catalyst, which points to the presence of a separate copper phase. Near-ambient pressure XPS shows that copper is in the metallic state. XPS of discharged catalysts evidenced that reaction at elevated pressure resulted in the surface reduction of Fe3+ to Fe2+. Copper promotion enhances CO conversion under high-temperature WGS conditions.