Promotional Effect on Selective Catalytic Reduction of NOx with NH3 over Overloaded W and Ce on V2O5/TiO2 Catalysts

Abstract

W and Ce are known to be a good promoters to improve selective catalytic reduction (SCR) activity for V2O5/TiO2 catalysts. This work aimed at finding the optimum ratio and loading of promoters (W and Ce) on V2O5/TiO2 catalyst in order to improve SCR reactivity in low temperature region and to minimize N2O formation in high temperature region. In addition, we changed the order of impregnation between W and Ce precursors on V2O5/TiO2 catalyst during the preparation and observed its effect on SCR activity and N2 selectivity. We utilized various analytical techniques, such as N2 adsorption‐desorption, X‐ray diffraction (XRD), and temperature‐programmed reduction with hydrogen (H2 TPR) to investigate the physicochemical properties of catalysts. It was found that W‐ and Ce‐overloaded V2O5/TiO2 catalyst such as W/Ce/V/TiO2 (15 : 15 : 1 wt%) showed the most remarkable DeNOx properties over the wide temperature region. Additionally, this catalyst significantly suppressed N2O formation during SCR reaction, especially in high temperature region (350–400°C). Based on the characterization results, it was found that such superior activity originated from the improved reducibility and morphology of W and Ce species on V2O5/TiO2 catalyst when they are incorporated together at high loading.