CrO_x/nano-Ce_0.60Zr_0.35Y_0.05O₂ catalysts that are highly selective for the oxidative dehydrogenation of isobutane to isobutene

Fluorite-type nanosized Ce_0.60Zr_0.35Y_0.05O₂ (nano-CZY) solid solution catalysts that are relatively uniform in particle size (4–5 nm) and y CrO_x/nano-CZY (y is the weight percentage of Cr₂O₃ ranging from 2 to 10 wt%) catalysts were prepared by the ethylene glycol-assisted CTAB-templated co-precipitation and incipient wetness impregnation methods, respectively. The materials were characterized by a number of analytical techniques and their catalytic performance was evaluated for the oxidative dehydrogenation of isobutane. The y CrO_x/nano-CZY catalysts show excellent activities, with the y = 8 wt% one performing the best (ca. 93% isobutene selectivity and ca. 10% isobutene yield at 540 °C and 30,000 mL/(g_cat h)). We conclude that the good reducibility of the highly dispersed CrO_x domains and the promotion of O₂ adsorption at oxygen vacancies of nano-CZY (for enhanced oxidation of the reduced catalyst) are responsible for the excellent performance of the 8 wt% CrO_x/nano-CZY catalyst.