Simultaneously Inhibiting SO<sub>2</sub> Oxidation and Improving deNO<i><sub><i>x</i></sub></i> Activity over the VMo/Ti Catalyst by Ce and P Comodification
Wenjie Liao, Ling Zhou, Xiaoqiang Wang, Yue Liu, Zhongbiao Wu
Abstract
Both improving the activity and reducing SO 3 emissions during selective catalytic reduction of NO x by the NH 3 (NH 3 –SCR) process over commercial V–Ti-based catalysts remain a challenge. Herein, Ce and P cooperatively modified the VMo/Ti catalyst to address this challenge. Within the temperature range of 250–350 °C, the optimal VMoCeP/Ti catalyst achieved a NO conversion of more than 95% and maintained a SO 2 oxidation ratio below 1.0%. The enhanced SCR activity of the modified catalyst could be attributed to the improvement in surface acidity and redox capacity by the addition of Ce and P, which would promote NH 3 adsorption and activation. Meanwhile, Ce and P coaddition could regulate the surface structure of vanadyl species from predominantly polymeric to a more dimeric form, which could also promote the SCR reaction. More importantly, except for the suppressed sulfation of vanadium species, both a lower proportion of polymeric vanadyl species and the strong interactions among V–Ce–P species could raise the energy barrier of the decomposition of sulfated vanadium species into SO 3, thereby inhibiting SO 2 oxidation. This work provided novel insights into developing efficient SCR catalysts with low SO 2 oxidation ratios for both the academic and industrial fields.