Influence of Mg Addition on the Catalytic Activity of Alumina Supported Ag for C3H6-SCR of NO
Influence of Mg Addition on the Catalytic Activity of Alumina Supported Ag for C3H6-SCR of NO
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DOI：
10.1007/s10562-009-9895-0
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发表时间：
2009-08-01
影响因子：
2.8
通讯作者：
Phil, Ha Heon
中科院分区：
文献类型：
--
作者：
Kumar, Pullur Anil;Reddy, Maddigapu Pratap;Phil, Ha Heon
研究了不同镁 (Mg) 重量百分比（1、2.5、5、7.5 和 10）对银 (3 wt%) 浸渍氧化铝 (SA) 催化剂对 C3H6 还原 NO 的影响。采用常规浸渍法制备了镁掺杂SA催化剂，并通过XRD、BET-SA、ICP-MS、XPS、SEM、UV-DRS、H-2-TPR和O-2-TPD进行了表征。通过 XRD 和 XPS 分析观察到 Mg 掺杂 SA 催化剂上存在 MgO 和 MgAl2O4 相。 5% Mg 掺杂 SA 催化剂 (Mg (5) SA) 上存在高百分比 MgAl2O4 相，增强了银相 (Ag2O) 的分散性和稳定性。 Mg (5) SA 催化剂在 SO2 (80 ppm) 存在下在低温 (350 A°C) 下表现出 51% 的高选择性（NO 至 N-2），并在宽温度范围 (350-500 A°C) 下保持高选择性。通过 XPS 分析，在 Mg (5) SA 催化剂上观察到 Ag-0 和 Ag+ 物质具有最佳的高表面利用率。 H-2-TPR 分析显示，与 SA 催化剂相比，Mg (5) SA 的高温还原峰较高。 XPS 分析证实 MgAl2O4 物质在 Mg (5) SA 催化剂上的利用率较高。 DRIFTS 研究揭示了低温下高活性 Mg (5) SA 催化剂还原 NO 过程中烯醇物种演化的分子证据。它还证实了烯醇物种与 NO + O-2 进一步转化为 -NCO 物种，并最终转化为 N-2 和 CO2。
The influence of different magnesium (Mg) weight percentages (1, 2.5, 5, 7.5 and 10) over silver (3 wt%) impregnated alumina (SA) catalyst was investigated for the reduction of NO by C3H6. Mg doped SA catalysts were prepared by conventional impregnation method and characterized by XRD, BET-SA, ICP-MS, XPS, SEM, UV-DRS, H-2-TPR and O-2-TPD. The existence of MgO and MgAl2O4 phases on Mg doped SA catalysts were observed from XRD and XPS analyses. Existence of high percentage MgAl2O4 phase on 5% Mg doped SA catalyst (Mg (5) SA) enhances the dispersion and stabilization of silver phases (Ag2O). Mg (5) SA catalyst shows a 51% of high selectivity (NO to N-2) in presence of SO2 (80 ppm) at low temperatures (350 A degrees C) and maintained high selectivity's with a wide temperature window (350-500 A degrees C). An optimal high surface availability of Ag-0 and Ag+ species were observed from XPS analysis over Mg (5) SA catalyst. H-2-TPR analysis shows high temperature reduction peak over Mg (5) SA compared to SA catalyst. XPS analysis confirms the high percent availability of MgAl2O4 species over Mg (5) SA catalyst. DRIFTS study reveals the molecular evidences for the evolution of enolic species during NO reduction over the highly active Mg (5) SA catalyst at low temperatures. It also confirms further transformation of enolic species into -NCO species with NO + O-2 and finally into N-2 and CO2.