Facet-Induced Strong Metal Chloride−Support Interaction over CuCl2/γ-Al2O3 Catalyst to Enhance Ethylene Oxychlorination Performance

The supported transition metal oxides, chlorides, carbides, and so forth (MXn), represent an important type of catalyst for redox processes. The MXn–support interaction, analogous to metal-support interaction, plays a critical role in redox reactions. Herein, we illustrated the nature of the monolayer CuCl2–γ-Al2O3 interaction, and its catalytic consequence induced by support facets in ethylene oxychlorination. Kinetic and theoretical studies, combined with operando spectroscopy demonstrated the effects of the interaction between CuCl2 with the various exposed facets of γ-Al2O3 (110) and (100). The catalyst with Al2O3(110) shows better performance with high activity, selectivity, and stability. The catalyst with the (111) facet deactivated rapidly, and the ethylene dichloride (EDC) selectivity decreased to 30%; while the activity on the catalyst with the (110) facet was much higher, with the EDC selectivity can be well kept at >99% in the long-term stability test. The multi-scale and in-depth characterizations revealed the concept of metal chloride–support interaction in determining the catalytic performance. We believe this method of tuning the reactivity of active species by manipulating their coordination with the support surfaces as a ligand shall spark inspiration for other catalytic applications.