Effect of Mo content on oxidative dehydrogenation of propane with CO₂ over ZnO_x catalysts supported on Mo-Zr mixed-oxides

The production of propylene from readily available propane sources is of great importance as it serves as a crucial building block for producing numerous value-added chemicals. Oxidative dehydrogenation of propane with carbon dioxide (ODPC) has been proposed as a viable and eco-friendly approach for simultaneous propylene production and carbon dioxide reduction. In this study, ZnOx catalysts were prepared by supporting them on a range of molybdenum-zirconium (Mo-Zr) mixed-oxides with varying Mo contents, aiming to utilize them for ODPC applications. The incorporation of suitable quantities of Mo in zirconium dioxide (ZrO2) supports increases the surface concentration and enhances the dispersion of ZnOx, thereby demonstrating promotional effects on the surface properties of the supported ZnOx catalysts. Notably, the ZnOx catalyst supported on a Mo-Zr mixed- -oxide, with an optimized Mo content, exhibits a propane conversion rate more than two-fold higher than that of the catalyst without Mo in ODPC. Furthermore, the introduction of Mo into the ZrO2 supports effectively inhibits the formation of coke by suppressing the cleavage of C-C bonds in propane. In comparison, the supported ZnOx catalysts with higher Zn loadings, show that a Mo-Zr mixed-oxide support effectively suppresses the formation of bulk ZnOx more than an unmodified ZrO2 support, leading to improved ODPC performance. The promoting effects of Mo emphasize the potential of utilizing mixed-oxide supports for ZnOx catalysts in ODPC, demon-strating a promising opportunity for enhancing catalytic performance.