Characterization of supported MoO₃ by temperature-programmed reduction

Temperature-programmed reduction (TPR) was employed for the characterization of molybdena catalysts. The effect of several variables on reduction of the supported catalysts was determined. The TPR spectra changed significantly with both the amount of MoO₃, from 5 to 80 wt %, and the type of support, several silica-alumina carriers, of compositions ranging from pure SiO₂ to pure Al₂O₃. The peak assigned to buildup of multilayers of molybdena on the γ-Al₂O₃ supports was affected by the calcination temperature and by the amount of promoter (0-5 wt % NiO). Nickel-promoted catalysts activated hydrogen easier than both cobalt-promoted and unpromoted catalysts.