Effects of Preparation Methods on the Catalytic Performance of Selective Catalytic Reduction of NO with CH4 over Co-MOR Catalysts

A series of Co-mordenite (MOR) catalysts prepared by ion-exchange or impregnation methods were used in the selective catalytic reaction of NO with methane (CH4-SCR). The structure and physicochemical properties of the catalysts were examined by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), UV-Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption of NO (NO-TPD). The Co species in the catalyst prepared by impregnation is present as Co3O4, whereas in the catalyst prepared by an ion-exchange method, the Co species enter in the mordenite skeleton with the ion form, and the more Co2+ and [Co-O-Co](2+) formed in the catalysts, the more uniform the adsorption of NO centers and the active centers of CH4-SCR. The catalysts prepared by different methods exhibited different activities for CH4-SCR. The catalysts prepared by ion-exchange exhibited activity over a wide activity temperature region, and NO conversion was over 50% at 327-450 degrees C on the Co(0.30)-MOR catalyst.