Strong Metal–Support Interactions between Copper and Iron Oxide during the High‐Temperature Water‐Gas Shift Reaction

• Published in: Angewandte Chemie (International ed.) Vol. 58; no. 27; pp. 9083 - 9087
• Main Authors: Zhu, Minghui, Tian, Pengfei, Kurtz, Ravi, Lunkenbein, Thomas, Xu, Jing, Schlögl, Robert, Wachs, Israel E., Han, Yi‐Fan
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.07.2019; Wiley Blackwell (John Wiley & Sons)
• Edition: International ed. in English
• Subjects: Catalysis; Catalysts; Catalytic activity; Copper; Copper oxides; Density functional theory; hydrogen; Interfaces; iron oxide; Iron oxides; metal–support interactions; Organic chemistry; Shift reaction; Surface structure; water-gas shift reaction; iron oxide; water-gas shift reaction; copper; hydrogen; metal-support interactions
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201903298

The commercial high‐temperature water‐gas shift (HT‐WGS) catalyst consists of CuO‐Cr2O3‐Fe2O3, where Cu functions as a chemical promoter to increase the catalytic activity, but its promotion mechanism is poorly understood. In this work, a series of iron‐based model catalysts were investigated with in situ or pseudo in situ characterization, steady‐state WGS reaction, and density function theory (DFT) calculations. For the first time, a strong metal‐support interaction (SMSI) between Cu and FeOx was directly observed. During the WGS reaction, a thin FeOx overlayer migrates onto the metallic Cu particles, creating a hybrid surface structure with Cu‐FeOx interfaces. The synergistic interaction between Cu and FeOx not only stabilizes the Cu clusters, but also provides new catalytic active sites that facilitate CO adsorption, H2O dissociation, and WGS reaction. These new fundamental insights can potentially guide the rational design of improved iron‐based HT‐WGS catalysts. Strong metal–support interactions between metallic copper and iron oxides were observed during the high‐temperature water‐gas shift (WGS) reaction. Such a synergistic interaction not only stabilizes the Cu clusters, but also provides new catalytic active sites that facilitate CO adsorption, H2O dissociation, and WGS reaction.