Study On Selective Catalytic Reduction Of NO_x With Ammonia Over Cu-Ce-Ti Catalysts

NH3-SCR is a widely used method to eliminate the NOx. In this experiments, a series of Cu-Ti, Ce-Ti and Cu-Ce-Ti catalysts has been prepared by hydrothermal(HT) method. The effection of temperature, GHSV and preparation method has been studied. Based on the study of Cu-Ti catalyst, we added Ce element to the Cu-Ti catalyst in order to improve the H2O and SO2resistance. The experiments results showed that the Cu-Ce-Ti catalyst with the molar ratio Cu:Ce:Ti=1:1:8has the best deNOx ability. At the temperature range from200to400, the NOx conversion could achieved90%. In some temperature point, the NOX conversion could reached100%. In the other way, we also study on the resistance to CO2, H2O and SO2, and the results showed the Cu-Ce-Ti catalyst has the very good resistance to those poisons.XRD and Raman spectrum indicated that Cu and Ce ions could be incorporated into the framework of the TiO2and the amorphous structure exists, which proved that Cu and Ce had highly dispersed over the TiO2. Cu-Ce-Ti catalyst showed a better redox ability than Cu-Ti and Ce-Ti catalyst which proved by H2-TPR results. XPS results showed the Cu element existed in Cu+and Cu2+state, Ce element existed in Ce3+and Ce4+, Ti element existed in Ti3+and Ti4+. So we think that two redox cycles (Cu2++Ce3+(?)Cu++Ce4+, Cu2++Ti3+(?)Cu++Ti4+) happened in the reaction. In situ DRIFTS results supported the above conclusion.