In this study, a series of CoCeO x catalysts were prepared by template, solid-state grinding with cobalt sulfate or cobalt acetate as the precursor and the oil bath method for catalytic reduction of NO x by CO (CO–NO). These catalysts were characterized by X-ray diffraction, Brunauer–Emmett–Teller, Raman spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction of H2, and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The results indicated that CoCeO x -TA and CoCeO x -SS catalysts exhibited much higher activity, which were attributed to excellent reducibility property, abundant chemical adsorbed oxygen, and NO absorption sites. In the presence of O2, the activity decreased obviously over CoCeO x -TA, CoCeO x -SS, and CoCeO x -SA catalysts. However, the activity increased at high temperatures over the CoCeO x -OA catalyst. According to the result of in situ DRIFTS, nitrate species decreased over CoCeO x -TA, CoCeO x -SS, and CoCeO x -SA catalysts in the presence of O2, which might inhibit the reduction efficiency of NO. Moreover, NO adsorption was not affected by O2 over CoCeO x -OA catalyst, which could contribute to its high activity in the CO-selective catalytic reduction reaction.