Characterization of monofunctional ZrO2-MoO3 catalysts for methylcyclopentane conversion

A series of ZrO2-MoO3 catalysts with different molybdenum loadings (0-18.7 at.% Mo) prepared by co-precipitation were characterized and evaluated for their performance for methylcyclopentane (mcp) conversion. The dependence of Mo content on the crystallinity, surface area, and acidic properties of ZrO2-MoO3 is studied and evaluated as a function of molybdenum loading. The monoclinic phase is observed at low Mo loadings, with the tetragonal polymorph of ZrO2 effectively stabilized at higher Mo loadings. The surface area of ZrO2-MoO3 increases with molybdenum content to a maximum value of 124 m2 g−1 at a loading of 15.8 at.% Mo, followed by a decrease at higher Mo loadings. Isothermal CO2 adsorption and ammonia TPD results indicate the strength of basic sites and specific NH3 desorption decreases with increasing molybdenum content, while TPR indicates ZrO2-MoO3 catalysts are more easily reduced with increasing molybdenum loading. The most active catalyst for mcp conversion (36% conversion) corresponds to a molybdenum loading of 3.2 at.% Mo, which has the highest acidity per surface area of the ZrO2-MoO3 catalysts studied.