Journal of Chemical Engineering of Japan, Vol.48, No.6, 463-471, 2015
The Optimization of Milling Parameters on the Activity for V2O5/TiO2 Catalysts by Mechanochemical Processing
The present study uses mechanochemical processing to alter the redox characteristics and low-temperature selective catalytic reduction (SCR) activity of vanadium oxide. The properties of the catalyst were studied using physicochemical analyses, including BET surface area measurements, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, H-2 temperature-programmed reduction (H-2-TPR), and UV/Vis diffuse reflectance spectroscopy (DRS). The prepared catalysts are named V/Ti, V/Ti-AM (attrition mill), V/Ti-BM (ball mill), and V/BM3 Ti (vanadium loaded after the TiO2 ball mill). The activity of the catalyst prepared by ball milling was the best because of the increase in the amount of lattice oxygen and surface-adsorbed oxygen that could participate in the reaction. In addition, the amount of vanadium oxide per unit volume increased, as did those of V5+, metastable V4+, and V3+. Raman spectroscopy demonstrated that the catalyst had the structure of monomeric V = O in crystalline V2O5 upon increasing the ball mill time to 10 h. This change in the structure influenced the reduction characteristics of the catalyst and decreased the maximum reduction temperature in H-2-TPR. When the ball-milling process was applied to a catalyst prepared by the wet-impregnation method for a certain time, the redox character was improved, and the activity of SCR could be increased at low temperature.