Tailoring Acidity of V/γ-Al2O3 by Mo Doping for Enhanced Propane Activation in Oxidative Dehydrogenation

Abstract

Mo- and V-based catalysts exhibit promising performance for low-temperature oxidative dehydrogenation of propane with oxygen (O2–ODHP), yet it remains difficult to achieve high propylene selectivity. The reaction requires efficient activation of C–H bonds while suppressing subsequent consecutive deep oxidation side reactions. In this work, highly dispersed V–Mo active sites were fabricated on γ-Al2O3 support by ball milling, forming highly dispersed Mo–V mixed-oxide-related domains associated with Mo4V6O25. The optimized 0.75 MVA catalyst achieved a propane conversion of 2.05% with a propylene selectivity of 90.04% at 160 °C. Multiple characterizations reveal that Mo doping modulates surface acidity and induces Mo–V electronic interaction. The tuned surface acidity promotes propane adsorption and C–H bond activation. Meanwhile, the modified surface oxygen environment together with weakened propylene adsorption effectively restrains the sequential oxidation of propylene into carbon oxides. Moreover, Mo incorporation enhances oxygen activation and replenishment, contributing to the regeneration of surface oxygen species under mild conditions. By synergistically regulating surface acidity, Mo–V electronic coupling and oxygen activation behavior, this study offers a practical strategy for designing low-temperature catalysts for propane oxidative dehydrogenation.