Abstract A series of TiO2-Al2O3 composites with Al/Ti molar ratios of 0.1, 0.2, and 0.4 were synthesized by a co-precipitation method and used as supports to prepare supported MnCeOx catalysts by an impregnation method. The physico-chemical properties of the samples were extensively characterized by N2 physisorption, XRD, Raman spectroscopy, SEM and EDS element mapping, XPS, H2-TPR, NH3-TPD, and in-situ DRIFTS. The catalytic activity and resistance to water vapor and SO2 of the as-prepared catalysts for the SCR of NOx with NH3 were evaluated at 50–250 °C and GHSV of 80,000 mL/(gcat∙h). The results reveal that MnCeOx/TiO2-Al2O3 exhibits higher activity and better SO2 tolerance than MnCeOx/TiO2. Combining with the characterization results, the enhanced activity and SO2 tolerance of MnCeOx/TiO2-Al2O3 can be mainly attributed to higher relative concentrations of Mn4+ and chemisorbed oxygen species, stronger reducibility, and larger adsorption capacity for NH3 and NO, which originates from the larger specific surface area and pore volume, higher dispersion of Mn and Ce species compared with MnCeOx/TiO2. Moreover, in situ DRIFTS was used to investigate the reaction mechanism, and the results indicate that the NH3-SCR reaction over MnCeOx/TiO2 and MnCeOx/TiO2-Al2O3 takes place by both the E–R and L–H mechanisms.

中文翻译：

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NO 在 MnCeO/TiO2 催化剂上的低温 NH3-SCR：通过用 Al2O3 改性 TiO2 提高活性和 SO2 耐受性✰

摘要 采用共沉淀法合成了一系列Al/Ti摩尔比为0.1、0.2和0.4的TiO2-Al2O3复合材料，并以浸渍法为载体制备负载型MnCeOx催化剂。样品的理化性质通过 N2 物理吸附、XRD、拉曼光谱、SEM 和 EDS 元素映射、XPS、H2-TPR、NH3-TPD 和原位 DRIFTS 进行了广泛表征。在 50–250 °C 和 80,000 mL/(gcat∙h) 的 GHSV 条件下，评估了所制备的用于 NH3 的 NOx SCR 的催化活性和对水蒸气和 SO2 的耐受性。结果表明，MnCeOx/TiO2-Al2O3 表现出比MnCeOx/TiO2 更高的活性和更好的SO2 耐受性。结合表征结果，MnCeOx/TiO2-Al2O3 增强的活性和 SO2 耐受性主要归因于更高的 Mn4+ 和化学吸附氧物种的相对浓度、更强的还原性以及更大的比表面积和孔体积对 NH3 和 NO 的吸附能力，与 MnCeOx/TiO2 相比，Mn 和 Ce 物种的分散度更高。此外，原位 DRIFTS 用于研究反应机理，结果表明 MnCeOx/TiO2 和 MnCeOx/TiO2-Al2O3 上的 NH3-SCR 反应通过 E-R 和 L-H 机制发生。