MnO2 loaded on activated carbon fibers (MnO2@ACF) were successfully prepared using co-precipitation methods, the as-prepared MnO2@ACF were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and N-2 adsorption/desorption analysis. The results showed that MnO2 particles were highly dispersed with a strong interaction between MnO2 particles and ACFs. MnO2 loaded on ACF can promote the catalytic oxidation efficiency of NO into NO2 remarkably, the loaded amount of MnO2 has an obvious effect on the NO oxidation efficiency over MnO2@ACF. The optimal amount of MnO2 for MnO2@ACF is 3.64 wt.%, and the oxidation efficiency of NO was increased from 20.1% over A15 to 30.6% over MnO2@ACF. (C) 2014 Elsevier B.V. All rights reserved.