Effect of SiO2 addition on NH4HSO4 decomposition and SO2 poisoning over V2O5–MoO3/TiO2–CeO2 catalyst

• Published in: Journal of environmental sciences (China) 2020-05, Vol.91, p.279-291
• Main Authors: Zheng, Chengqiang, Cheng, Teng, Yang, Linjun, Wu, Hao, Fan, Hongmei
• Format: Article
• Language: English
• Subjects: CeO2-doped SCR catalyst; Cerium sulfate; NH4HSO4 decomposition; SiO2 addition; SO2 poisoning
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2020.01.011

The deposition of NH4HSO4 and the poisoning effect of SO2 on SCR catalyst are the main obstacles that restrict the industrial application of CeO2-doped SCR catalysts. In this work, deposited NH4HSO4 decomposition behavior and SO2 poisoning over V2O5–MoO3/TiO2 catalysts modified with CeO2 and SiO2 were investigated. By the means of characterization analysis, it was found that the addition of SiO2 into VMo/Ti–Ce had an impact on the interaction existed between catalyst surface atoms and NH4HSO4. Temperature-programmed methods and in situ diffused reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments indicated that the doping of SiO2 promoted the decomposition of deposited NH4HSO4 on VMo/Ti–Ce catalyst surface by reducing the thermal stability of NH4HSO4 and enhancing the NH4HSO4 reactivity with NO in low temperature. And this improvement may be the reason for the better catalytic activity than VMo/Ti–Ce in the case of NH4HSO4 deposition. Accompanied with cerium sulfate species generated over catalyst surface, the conversion of SO2 to SO3 was inhibited in SiCe mixed catalyst. The addition of SiO2 could promote the decomposition of cerium sulfate, which may be a potential strategy to enhance the resistance of SO2 poisoning over CeO2-modifed catalysts. [Display omitted]