The synergistic promotional effect of W doping and sulfate modification on the NH3-SCR activity of CeO2 catalyst

Abstract

As the accelerator of the surface acid site, sulfate modification or the doped tungsten has usually been used to improve the NH3-SCR activity of CeO2, but the former also had been confirmed to be poisoning on the activity of cerium-tungsten-based catalyst. Herein, the synergistic promotional effect of W doping and sulfate modification has been achieved on the NH3-SCR activity of CeO2 synthesized via the one-pot hydrothermal method, and Ce0.95W0.05Oz-TA possesses the optimal de-NOx performance in the temperature range of 150⁓400 °C. The characterization results indicated that on the basis of sulfate modification, the doping of W contributes to improving the dispersion of Ce and sulfate species on the surface of CeO2-TA, and regulating the amount of sulfate adsorbed on the catalyst surface. Moreover, the synergistic effect of W doping and sulfate modification improves the acid sites and reducibility of CeO2, especially increasing the abundance and strength of Brønsted acid sites. The doping of W contributes to the redox cycle of Ce3+ + W6+ ↔ Ce4+ + W5+ occurred on the surface of both Ce0.95W0.05Oz and Ce0.95W0.05Oz-TA. And this synergistic interaction of W doping and sulfate modification could induce severe structural distortion with the abundance of oxygen vacancies and surface chemisorbed oxygen formed, thereby increases the NH3-SCR activity of CeO2.