A modification route of nanocarbon catalyst based on Grignard reagent reduction of oxidized carbon nanotubes (o-CNTs) has been developed for oxidative dehydrogenation (ODH) of n-butane. The o-CNTs contain considerable amount of electrophilic oxygen species which are responsible for deep oxidation side-reactions and the alkene selectivity in ODH is low. After Grignard reduction, the corresponding electrophilic oxygen groups on the surface of the catalyst were eliminated and the basicity increased. As a result, the side-reactions in ODH were prohibited and the alkene selectivity was significantly improved compared with o-CNTs. The chlorine containing Mg/Cl species were found to have positive effect on the improvement of C4H8 alkene yield. This study provides a method of the preparation of nanocarbon catalyst to achieve higher alkene selectivity for the dehydrogenation reaction. (C) 2018 Elsevier Inc. All rights reserved.