Characterization and catalytic performance of vanadium supported on sulfated Ti-PILC catalysts issued from different Ti-precursors in selective catalytic reduction of nitrogen oxide by ammonia

Abstract

Vanadium supported on sulfated Ti-pillared clay catalysts (STi-PILCs) issued from different Ti-precursors were investigated for selective catalytic reduction (SCR) of NO by NH3 in the presence of O2. The STi-PILCs supports were prepared by hydrolysis of a series of organic or inorganic Ti-precursors; Ti(OCH3)4, Ti(OC2H5)4, and TiCl4 with H2SO4, and then modified with vanadium introduced by impregnation method. The unpromoted and promoted vanadium pillared clays were characterized using chemical analysis, N2-physisorption, NH3-TPD, H2-TPR, and tested for SCR of NO by NH3. It was found that the textural and acidic properties of the STi-PILC materials are influenced by the nature of the Ti-precursor; and the use of Ti-methoxide allows the synthesis of STi-PILC with the highest acidity. The presence of vanadium on STi-PILC supports reduces their surface areas and porous volumes, creates new redox sites, and enhances the reducibility of the sulfate groups leading to better redox properties of the binary V-STi-PILCs. After vanadium addition, the STi-PILC materials issued from Ti(OCH3)4, exhibited higher NO reduction activity at high temperature. These results underline the importance of the Ti-precursor for the preparation of the STi-PILC support, and the role of vanadium to increase the redox properties of V-STi-PILC catalyst for the SCR of NO by NH3.