A series of alkali metal doped natural manganese ore (NMO) catalysts were prepared by an impregnation method, and tested for the complete catalytic oxidation of o-xylene. The effects of alkali metal on the catalytic performance and structural properties of NMO were examined. Alkali metals were found to enhance the activity of NMO in the following order: Li < Na < Rb < K, Cs. The experimental results showed that NMO-K(Cs)-0.07 could convert o-xylene (0.055 vol.%) into CO(2) and H(2)O at 240 degrees C, which was 60 degrees C lower than that of NMO. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) measurements revealed that the primary component of NMO and NMO-K-0.07 were MnO(2). It was found that K(2)O was highly dispersed onto the NMO surface. The addition of K(2)O did not increase the BET surface area of the NMO. However, it resulted in the binding energy of the Mn 2p of NMO-K-0.07 shifted to a lower value. The results suggested that alkali metals act as electronic promoters, indicating that alkali metal doped NMO are promising catalyst candidates for the catalytic oxidation of VOCs. (C) 2011 Elsevier B.V. All rights reserved.