Selective Catalytic Reduction (SCR) Of NOx By Methane In The Prensence Of Oxygen

Nitrogen oxide is one of the main pollutants, which is released in the prensence of excess oxygen. So the selective catalytic reduction (SCR) of NOx to N2 in the prensence of excess oxygen is an important commercial process to remove pollutants from exhaust fumes. Since mehane is cheap and easy to gain, the using of methane as reducing reagent has attracted particular interest. But the catalysts used in CH₄-SCR NOx reaction are sensitive to the reaction conditions. So it is important to improve the activity and selectivity of these catalysts. In this paper, the preparation method and properties of supports were studied in detail. The catalysts that have high activity and good selectivity were prepared by optimizing supports and activity reagents.La-Al₂O₃ was prepared by several methods and characterized by Brunauer-Emmett-Teller (BET) and X-ray diffraction (XRD). The results reveal that La-Al₂O₃ can keep good surface area and restrainγ-Al₂O₃ to turn intoα-Al₂O₃ after aged. Ce-Zr-O and Ce-Zr-Mn-O compound oxides (namely oxygen storage materials OSM) were prepared by co-precipitation. We studied the performance of OSM with different Ce-Zr radio which were characterized by oxygen storage capacity (OSC), BET, XRD and temperature-programmed reduction (TPR). The results reveal that Ce_0.63Zr_0.37O₂ solid solution has high OSC, great surface areas, appropriate pore diameter distribution and excellent thermal stability. Moreover,...