Exclusive effect of different transition metals supported on wti-pillared clay: surface acidity and redox properties

Different transition metals (Mo, Cu, Mn,Ce, V, Co,Zr) supported on WTi-pillared clay were characterized by different techniques and tested in the selective catalytic reduction of nitrogen oxide by ammonia. The effects of diverse transition metals on the textural parameters, the acidity and the redox propertieswerecompared to, then correlated with the catalytic activities. The results demonstrate that the surface propertiesof the investigated materials are largely dependenton the type of transition metal added to the support. The vanadium addition significantly improves the total acidity, which were beneficial for the selective catalytic reduction of nitrogen oxide by ammonia. However, the presence of copper enhances largely the catalyst redox capacity compared to all the other transition metals. The reactivity of the samples containing the metal follows this order: V >> Cu > Ce > Mo > Mn > Co ≈ Zr ≈ the support. The highest efficiency of the best catalysts is directly related to the strongest acidity with moderate redox properties or the inverse.