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New Mn-TiO 2 aerogel catalysts for the low-temperature selective catalytic reduction of NO x
Journal of Sol-Gel Science and Technology ( IF 2.3 ) Pub Date : 2021-01-16 , DOI: 10.1007/s10971-020-05451-4
Jihene Arfaoui , Abdelhamid Ghorbel , Carolina Petitto , Gerard Delahay

A new series of Mn-based catalysts (Mn-TiO2, Ce-Mn-TiO2, Mn-TiO2-SO42, and Ce-Mn-TiO2-SO42–) were successfully elaborated using the sol–gel method associated with supercritical drying approach for the low-temperature NO-SCR by NH3. The physicochemical properties of aerogel powders were examined by XRD, N2-Physisorption at 77 K, NH3-TPD, H2-TPR, and DRUV-Vis spectroscopy. It was shown that all the catalysts develop essentially the diffraction peaks of TiO2 anatase phase and are characterized by a nanometer size (ranging between ~5 and 9 nm), developed mesoporous texture, high surface area (SBET > 104 m2/g) and large porosity (VPT > 0.24 cm3/g). The incorporation of Ce and/or SO42– influences differently the structural, textural, acidic, and redox properties of Mn-derived sol–gel catalysts and consequently affects their SCR activity. High NO conversions (>75%) into essentially N2O are obtained at low temperatures (150–270 °C) over Mn-TiO2 and Ce-Mn-TiO2 aerogel systems. The addition of sulfate modifies the nature of Mn species and noticeably reduces the low-temperature reactivity of catalysts (T < 300 °C). However, it induces, thanks to the contribution of many strong acid sites, a substantial increase of the NO conversion into N2 at higher temperatures (T > 300 °C) leading to highly active and N2-selective Mn-TiO2-SO42– and Ce-Mn-TiO2-SO42– sulfated catalysts. Above 90% NO conversion into N2 (100%) was reached, in the NO-SCR by NH3, over the new Ce-Mn-TiO2-SO42– aerogel catalyst, in the 450–500 °C temperature range.



中文翻译:

用于低温选择性催化还原NO x的新型Mn-TiO 2气凝胶催化剂

一系列新的Mn系催化剂(锰的TiO 2,Ce的锰的TiO 2,锰的TiO 2 -SO 4 2 - ,和Ce锰的TiO 2 -SO 4 2-)使用溶胶成功阐述-凝胶法与NH 3低温NO-SCR的超临界干燥方法相关。通过XRD,77 K下的N 2-物理吸附,NH 3 -TPD,H 2 -TPR和DRUV-Vis光谱检查气凝胶粉末的理化性质。结果表明,所有催化剂都基本形成了TiO 2的衍射峰。锐钛矿相的特征在于纳米尺寸(约5至9 nm),发达的中孔织构,高表面积(S BET  > 104 m 2 / g)和大孔隙率(V PT  > 0.24 cm 3 / g)。Ce和/或SO 4 2–的掺入对Mn衍生的溶胶-凝胶催化剂的结构,质构,酸性和氧化还原特性产生不同的影响,因此影响其SCR活性。在低温(150–270°C)下,在Mn-TiO 2和Ce-Mn-TiO 2上获得高的NO转化率(> 75%),基本上转化为N 2 O气凝胶系统。硫酸盐的加入改变了锰的性质,并显着降低了催化剂的低温反应性(T  <300°C)。然而,由于许多强酸位点的作用,在较高温度(T  > 300°C)下,NO大量转化为N 2会导致高活性和N 2-选择性Mn-TiO 2 -SO的转化。4 2–和Ce-Mn-TiO 2 -SO 4 2–硫酸化催化剂。在新的Ce-Mn-TiO 2 -SO 4上,NH 3在NO-SCR中达到90%以上的NO转化为N 2(100%)。2-气凝胶催化剂,温度范围为450-500°C。

更新日期:2021-01-18
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