Cr₂O₃ Clusters on ZnO as Hydrogen Pools for Efficient Syngas‐To‐Light Olefins

Abstract

Interfaces of mixed oxide are often considered the primary catalytic sites, yet the functionalities of the surrounding environments are less understood. Composite oxides, particularly ZnO‐Cr2O3, show high activity and selectivity for syngas conversion, with ZnO dissociating H2 to hydrides and Cr2O3 activating CO. However, hydrides on ZnO cannot remain stable at temperatures above room temperature. Focusing on the puzzlingly high performance despite ZnO’s inability to stabilize active hydrides at reaction temperatures (300‐400 oC), we clarified the roles of each phase using models of Cr2O3/ZnO and ZnO/Cr2O3. Cr2O3 clusters on ZnO effectively stabilize and store hydrides, significantly enhancing syngas conversion compared to individual oxides or ZnO/Cr2O3. An acetate/ketene pathway on Cr2O3/ZnO was identified, driven by the unique role of Cr2O3 clusters in regulating local hydride and CO coverages, unlike other routes observed on ZnO/Cr2O3. These insights advance the understanding of the active structures and functionalities of mixed oxides in catalysis.