Effect of promoters including tungsten and barium on the thermal stability of V₂O₅/sulfated TiO₂ catalyst for NO reduction by NH₃

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• 作者：Jin Woo Choung ; In-Sik Nam and Sung-Won Ham
• 关键词：SCR ; Sulfated TiO₂ ; Tungsten ; Barium ; Thermal stability ; Vanadyl phase ; Titania phase
• 刊名：Catalysis Today
• 出版年：2006
• 期刊代码：13_09205861
• 类别：ce
• 出版时间：15 February 2006
• 卷：111
• 期：3-4
• 页码：242-247
• 文件大小：370 K

摘要

The effect of tungsten and barium on the thermal stability of V₂O₅/TiO₂ catalyst for NO reduction by NH₃ was examined over a fixed bed flow reactor system. The activity of V₂O₅/sulfated TiO₂ catalyst gradually decreased with respect to the thermal aging time at 600 °C. The addition of tungsten to the catalyst surface significantly enhanced the thermal stability of V₂O₅ catalyst supported on sulfated TiO₂. On the basis of Raman and XRD measurements, the tungsten on the catalyst surface was identified as suppressing the progressive transformation of monomeric vanadyl species into crystalline V₂O₅ and of anatase into rutile phase of TiO₂. However, the NO removal activity of V₂O₅/sulfated TiO₂ catalyst including barium markedly decreased after a short aging time, 6 h at 600 °C. This may be due to the transformation of vanadium species to inactive V–O–Ba compound by the interaction with BaO which was formed by the decomposition of BaSO₄ on the catalyst surface at high reaction temperature of 600 °C. The addition of SO₂ to the feed gas stream could partly restore the NO removal activity of thermally aged V₂O₅/sulfated TiO₂ catalyst containing barium.