• CrO x /CeZrO 2 could catalyze CO 2 oxidative dehydrogenation of n -butane to butadiene. • The optimal 10%CrO x /Ce 0.5 Zr 0.5 O 2 catalyst possessed a high Cr6+/Cr3+ ratio. • The balanced acidic and basic sites of the catalyst were crucial for the reaction. • CO 2 could greatly boost the n -butane dehydrogenation to butadiene. 1,3-Butadiene (BD) is a key raw material for the synthesis of rubber, but its efficient synthesis is a challenge. Direct dehydrogenation of n -butane in CO 2 (CO 2 ODHB) represents an ideal way to produce BD and use the waste CO 2 source. In the present work, several catalysts of CrO x supported on CeZr solid solutions were developed and applied in catalyzing the CO 2 ODHB to BD. Among these, a 10%CrO x /Ce 0.5 Zr 0.5 O 2 could achieve the reaction with 25% of n -butane conversion and 70% of BD selectivity at 823 K. The prepared catalysts were characterized using the techniques of XRD, UV–vis-DR, XPS, Raman, N 2 adsorption/desorption, FT-IR, TEM, H 2 -TPR, NH 3 -TPD, and CO 2 -TPD, etc. The results indicated that compared with other catalysts, the 10% CrO x /Ce 0.5 Zr 0.5 O 2 catalyst possessed the highest Cr6+ species concentration and balanced acidic-basic sites, contributing to the outstanding performance in the reaction. These findings provide a strategy to build a catalyst with the stable valence of Cr6+ species, and hopefully, offer an important reference to establish other CeZr solid solution catalysts with regulable acidic-basic and textural properties. [Display omitted] [ABSTRACT FROM AUTHOR]