Data from: Sulfur resistance of Ce-Mn/TiO2 catalysts for low-temperature NH3–SCR

Ce-Mn/TiO2 catalyst prepared using a simple impregnation method demonstrated a better low-temperature selective catalytic reduction of NO with NH3 (NH3-SCR) activity in comparison with the sol-gel method. The Ce-Mn/TiO2 catalyst loading with 20% Ce had the best low-temperature activity and achieved a NO conversion rate higher than 90% at 140-260°C with a 99.7% NO conversion rate at 180 °C. The Ce-Mn/TiO2 catalyst only had a 6% NO conversion rate decrease after 100 ppm of SO2 was added to the stream. When the SO2 was removed from the stream, the catalyst was able to recover completely. The crystal structure, morphology, textural properties, and valence state of the metals involving the novel catalysts were investigated using X-ray diffraction (XRD), N2 adsorption and desorption analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS), respectively. The decrease of NH3-SCR performance in the presence of 100 ppm SO2 was due to the decrease of the surface area, change of the pore structure, the decrease of Ce4+ and Mn4+ concentration, and the formation of the sulfur phase chemicals which blocked the active sites and changed the valence status of the elements.采用简单浸渍法制备的Ce-Mn/TiO₂催化剂，相较于溶胶-凝胶法制备的同类样品，展现出更优异的低温氨选择性催化还原NO（NH₃-SCR）性能。其中负载20% Ce的Ce-Mn/TiO₂催化剂低温活性最佳，在140~260℃区间内NO转化率高于90%，在180℃时NO转化率可达99.7%。当通入100ppm的SO₂后，该催化剂的NO转化率仅下降6%；移除气流中的SO₂后，催化剂性能可完全恢复。本研究分别通过X射线衍射（X-ray diffraction, XRD）、N₂吸附-脱附分析、X射线光电子能谱（X-ray photoelectron spectroscopy, XPS）、扫描电子显微镜（scanning electron microscopy, SEM）以及能量色散光谱（energy dispersive spectroscopy, EDS），对该新型催化剂的晶体结构、形貌、织构性质以及所涉及金属的价态进行了表征。在100ppm SO₂存在时NH₃-SCR性能下降的原因在于：比表面积降低、孔结构发生改变、Ce⁴+与Mn⁴+浓度下降，同时生成了硫化物相物质，其会堵塞活性位点并改变元素的价态状态。