Abstract: Dehydrogenation of isobutane to isobutene in the presence of carbon dioxide was carried out over NiO/Al₂O₃ catalyst and the effect of K₂O additive on its catalytic behavior was investigated. Compared with the reaction in an inert atmosphere, the dehydrogenation of isobutane is coupled with the reverse water-gas shift by conducting the reaction in carbon dioxide, which can then enhance the isobutene yield. The addition of K₂O in the NiO/Al₂O₃ catalyst can decrease its acidity, alleviate the deep reduction of NiO active species during the reaction and then suppress the side reactions like cracking and coke formation; these are helpful to enhance the isobutene yield and to improve the catalyst stability.