Nitrogen dioxide (NO2) as an oxidative agent can efficiently react with multi-walled carbon nanotubes (CNTs) and sequentially introduces large quantities of oxygen functional groups on the surface. The produced NO can be easily oxidized by O-2 into NO2, achieving an almost close cycle of NOx. NO2 is more favorable to generate active qunione groups on CNTs surface and improve the specific surface area of CNTs. The NO2-treated CNTs show the superior catalytic performance for oxidative dehydrogenation of propane. This work provides an applicable and efficient method for the mass functionalization of CNTs and other carbon materials. (C) 2013 Elsevier Ltd. All rights reserved.