Study On F Mn-Cu-Ce-Fe/V/TiO₂Catalyst For Selective Catalytic Reduction And Resistance To SO₂

The selective catalytic reduction （SCR） is an important technology to control NO_x fromstationary soursces. However, the synthesis of catalyst with high efficiency still remains oneof the difficult work.A series of catalysts were prepared by dip method to improve the catalyst activity in thelow temperature and SO₂resistance. Mn, Cu, and, Ce, V2O5and WO3loaded on TiO₂werecharacterized for the selective catalytic reduction （SCR） of NO, SO₂resistance, BET, SEM,XRD, NH₃-TPD and EDS.Accoroding to the research of catalyst （Mn-Ce/V-W/TiO₂、Cu-Ce/V-W/TiO₂andFe-Ce/V-W/TiO₂）, the best content of Cu, Mn, Fe loading was gained respectively. The resultsshows when the content of Mn, Cu and Fe were10%,6%and5%respectively, had goodNO conversion. It showed that NO conversion on Mn-Ce/V-W/TiO₂was88%,Cu-Ce/V-W/TiO₂was85%at430℃, Fe-Ce/V-W/TiO₂was73%at430℃. In the presence ofSO₂, the NO conversion of Fe-Ce/V-W/TiO₂catalyst was not decreasd much wich exhibit astrong resistance of SO₂.The reseach showed that the NO conversion on Mn-Cu-Ce/V-W/TiO₂was92%at430℃,Cu-Fe-Ce/V-W/TiO₂was84%at270℃, Mn-Fe-Ce/V-W/TiO₂was61%at190℃. Addition ofMn phase and Fe phase could enhance the NO conversion much more at low temperatures.The improvement of Mn and Fe phase is much more pronounced than in the case of Cu phaseat low temperatures and in reverse at higher temperatures.The Mn-Cu-Fe-Ce/V-W/TiO₂catalysts used for selsctive catalytic reduction of NO_xwere prepared by loading different amount of Mn, Cu, Fe, V on the TiO₂paticles and differentcalcination temperature to find the best preparation method of catalyst. When the Mn, Cu, Feand V loading was10%,6%,5%and3%, respectively, the NO removal activity was the best.The NO conversion on Mn-Cu-Fe-Ce/V-W/TiO₂was91%and92%at350℃and430℃,respectively. The results showed that the NO conversion was decreased obviously as theincrease of calcination temperature. When the calcation temperature was400, the NO removalactivity was the best. The results showed the the catalysts which prepared by Mn（CH3OO）2were much better than the catalysts which prepared by Mn（NO3）2. In the presence of SO₂, theNO conversion of Mn-Cu-Fe-Ce/V-W/TiO₂catalyst decreased23%at190℃. As the temperature was rasied, the NO conversion was increased too. When the temperature wasreached at350℃, the NO removal activity was same with the catalyst which was notpoisoned. The catalyst which prepared by CuSO4exhibited a stronger resistance of SO₂thancatalyst which prepared by Cu（NO3）2.BET were used to characterize the catalyst. The result showed that the larger surfaceareas of catalyst could improve the NO removal activity of catalyst. NH₃-TPD showed thatbinary and Ternary composite catalyst had two peak（α and β） and Mn-Cu-Fe-Ce/V-W/TiO₂catalysts had three peak（α、β and γ）. And there was a linear relationship between peaktemperature or peak area and activity. The XRD of catalysts showed that Mn2O3、CuO andFe2O3peaks appeared while increased the content of Mn、Cu and Fe, respectively. Thesepeaks would effected of catalyst activity. SEM were used to characterize Surface Topographyof the catalyst. The result showed that catalyst particles of spherical shape with more evenlydistributed, more holes and microporous, was helpful for the catalyzed activity.