Novel V2O5-CeO2-TiO2-SO42- nanostructured aerogel catalyst for the low temperature selective catalytic reduction of NO by NH3 in excess O2
Novel V2O5-CeO2-TiO2-SO42- nanostructured aerogel catalyst for the low temperature selective catalytic reduction of NO by NH3 in excess O2
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DOI：
10.1016/j.apcatb.2017.10.059
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发表时间：
2018-05-01
影响因子：
22.1
通讯作者：
Delahay, Gerard
中科院分区：
文献类型：
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作者：
Arfaoui, Jihene;Ghorbel, Abdelhamid;Delahay, Gerard
采用一步溶胶-凝胶法结合超临界干燥工艺，开发了用于柴油DeNO(x)技术的新型氧化铈和硫酸盐共改性V2O5-TiO2气凝胶催化剂。采用N-2吸附-解吸、XRD、H-2-TPR、NH3-TPD、Raman和DRUV-Vis光谱对TiO2、V2O5-TiO2、V2O5-CeO2-TiO2和V2O5-CeO2-TiO2- so42 -气凝胶材料的理化性质进行了表征。利用XPS进一步了解了新型V2O5-CeO2-TiO2-SO42-气凝胶催化剂表面活性位点的氧化态。表征结果表明，成功合成了具有高表面积、大孔隙率和良好热稳定性的新一代纳米结构良好的气凝胶催化剂。V、Ce和SO42-活性物质高度分散在TiO2表面，它们的存在对气凝胶催化剂的表面酸度和氧化还原性能有很大影响。硫酸盐阴离子产生了强酸位点，很可能有助于V和Ce表面物质分别稳定在4 +和3 +氧化态。富氧条件下NH3催化scno，在150 ~ 500℃温度范围内，V2O5-TiO2气凝胶催化剂的NO转化率较低。铈的加入显著提高了低温（220 ~ 400℃）下NO的转化率。然而，铈和硫酸盐的同时加入导致了一种新型的V2O5-CeO2-TiO2-SO42-纳米结构气凝胶催化剂，在高温（450-500℃）下具有优于V2O5-WO3/TiO2商业催化剂（EUROCAT）的催化性能。
New ceria and sulfate co-modified V2O5-TiO2 aerogel catalysts were developed, using the one-step sol gel method associated with the supercritical drying process, for Diesel DeNO(x) technology. N-2 adsorption-desorption, XRD, H-2-TPR, NH3-TPD, Raman and DRUV-Vis spectroscopy were employed to probe the physico-chemical properties of TiO2, V2O5-TiO2, V2O5-CeO2-TiO2 and V2O5-CeO2-TiO2-SO42- aerogel materials. XPS was used to obtain further information about the oxidation states of the active sites on the surface of the novel V2O5-CeO2-TiO2-SO42- aerogel catalyst. The characterization results showed the successful synthesis of a new generation of well nanostructured aerogel catalysts with high surface area, large porosity and good thermal stability. V, Ce and SO42- actives species were found highly dispersed on TiO2 surface and their presence strongly influenced the surface acidity and the redox properties of the aerogel catalysts. Sulfate anions created strong acid sites and most probably contributed to the stabilization of V and Ce surface species at their 4 + and 3 + oxidation state, respectively. In the SCR-NO by NH3 under oxygen rich conditions, V2O5-TiO2 aerogel catalyst exhibited low NO conversions in 150-500 degrees C temperature range. The addition of cerium significantly increased the NO conversion at low temperature (220-400 degrees C). However, the simultaneous incorporation of cerium and sulfate has led to a novel V2O5-CeO2-TiO2-SO42- nanostructured aerogel catalyst with superior catalytic performances, at high temperature (450-500 degrees C), with respect to V2O5-WO3/TiO2 commercial one (EUROCAT).