Promoter effect of V2O5/TiO2 catalyst on deNOx activity and N2O formation in the selective catalytic reduction of NO with NH3

Introduction Nitrogen oxides (NOx) cause the photochemical smog, acid rain, ozone depletion and greenhouse effect. Therefore, a great deal of studies has been performed to reduce NOx by using various catalytic systems such as selective catalytic reduction (SCR) or NOx storagereduction catalyst. Recently, N2O, whose greenhouse effect is 310 times larger than CO2, has been issued due to the new regulatory trend [1]. N2O is known to be an undesirable product of SCR system (e.g. V2O5/TiO2 catalyst), especially at higher temperature than 300C. Here we aimed at finding the optimum condition to prepare V2O5/TiO2 SCR catalyst with excellent deNOx activity and minimized N2O formation by changing the various parameters such as promoters and the order of impregnation.V2O5/TiO2 catalysts with various promoters, for example, W [2], Zr, Zn Ga, Mo, Mn, Cr and Ce were prepared. In addition, we changed the sequence of impregnation between promoters and vanadium precursor, and also introduced co-impregnation method. Thus, the effect of loading method and the type of promoters on the activity and the selectivity during SCR reaction was extensively investigated.