The role of cerium in the improved SO₂ tolerance for NO reduction with NH₃ over Mn-Ce/TiO₂ catalyst at low temperature

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• 作者：Ruiben Jin ; Yue Liu ; Yan Wang ; Wanglai Cen ; Zhongbiao Wu ; Haiqiang Wang ; Xiaole Weng
• 关键词：Nitrogen oxides ; SCR ; Low-temperature ; DRIFT ; SO2 tolerance
• 刊名：Applied Catalysis B: Environmental
• 出版年：27 April, 2014
• 年：2014
• 卷：148-149
• 期：Complete
• 页码：582-588
• 全文大小：1138 K

文摘

Manganese-based catalysts have shown excellent low-temperature selective catalytic reduction (SCR) activity for NO_x removal. However, they all suffer from the serious SO₂ poisoning effect on activity. Ceria modification has been reported to be able to promote SO₂ tolerance of SCR catalysts probably via the inhibition of surface sulfate species formation. In this study, in situ diffuse reflectance infrared transform spectroscopy (DRIFT) investigations were carried out to determine the role of Ceria in the improved resistance for a Ce-modified Mn/TiO₂ catalyst. The results indicated that after the introduction of Ce, SO_x ad-species preferentially formed on Ceria as bulk-like sulfate species and lessened the sulfation of the main active phase (MnO_x) during low-temperature SCR processes in the presence of SO₂. Furthermore, the DRIFT and TG-DSC results also implied that Ce modification could reduce thermal stabilities of the sulfate species covered on catalyst surface, thereby promoting its decomposition. Both of these would be beneficial to the improved SO₂ tolerance of Ce modified catalysts.