Evaluation of NO Oxidation Properties over a Mn-Ce/ γ -Al 2 O 3 Catalyst

With the purpose of studying the effect of diesel oxidation catalyst (DOC) on the NO oxidation activity, a series of x Mn10Ce/ γ -Al 2 O 3 ( x = 4, 6, 8, and 10) catalysts were synthesized by acid-aided sol-gel method. The physicochemical properties of the catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Transmission Electron Microscope (TEM). Result showed that the crystalline size of MnO x and CeO 2 ranges from 5 nm to 30 nm and manganese existed mainly in the catalysts in the form of manganese dioxide. Moreover, NO oxidation experiments were carried out to evaluate the activity of the catalysts; according to the results, 6Mn10Ce/ γ -Al 2 O 3 catalyst showed the supreme NO oxidation activity with a NO to NO 2 conversion rate of 83.5% at 300°C. Compared to 500 ppm NO inlet concentration, the NO conversion was higher than that of 750 and 1000 ppm NO over 6Mn10Ce/ γ -Al 2 O 3 catalyst in the temperature range of 150–300°C.