Abstract Nb doped MnCe0.2Ox complex oxides catalysts prepared via a homogeneous precipitation method were investigated for synergistic catalytic removal of NOx and chlorobenzene (CB) at low temperatures. The MnNb0.4Ce0.2Ox catalyst with a molar ratio of Nb/Mn = 0.4 exhibits excellent activity and the NOx and CB removal efficiency reaches 94.5% and 96% at 220 °C, respectively. Furthermore, the NOx and CB removal efficiency of MnNb0.4Ce0.2Ox still remains above 80% after injecting 300 ppm SO2 and 7 vol% H2O for 36 h. In addition, the presence of CB and NOx + NH3 can improve the NOx and CB removal efficiency of MnNb0.4Ce0.2Ox, respectively. The analysis results from N2-BET, Py-IR, H2-TPR and NH3-TPD reveal that the introduction of Nb increases the average pore size, pore volume and surface area, promoted the growth of Lewis acid amount obviously, and enhances redox ability of MnCe0.2Ox at 100–250 °C. Moreover, the molecular migration process of NOx, NH3, CB and SO2 in NH3-SCR and CB oxidation reaction over MnNb0.4Ce0.2Ox catalysts were systematically studied. In situ DRIFTS, FT-IR and XPS also confirm that the adsorption of sulfate species and SO2 on the surface of MnNb0.4Ce0.2Ox is inhibited effectively by the introduction of Nb in the presence of SO2 and H2O. Moreover, Nb additives also enhance the structural stability of MnNb0.4Ce0.2Ox, due to the interactions among Mn, Nb and Ce. The NH3-TPD, H2-TPR and in situ DRIFTS results also confirm that the MnNb0.4Ce0.2Ox still retains abundant acid sites and high redox ability in the presence of SO2 and H2O. In summary, MnNb0.4Ce0.2Ox catalysts represent a promising and effective candidate for controlling NOx and CB at low temperatures.

中文翻译：

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MnNb0.4Ce0.2O催化剂协同催化去除垃圾焚烧尾气中氯苯和NO的性能与机理研究

摘要 研究了通过均相沉淀法制备的 Nb 掺杂 MnCe0.2Ox 复合氧化物催化剂在低温下协同催化去除 NOx 和氯苯 (CB)。摩尔比为 Nb/Mn = 0.4 的 MnNb0.4Ce0.2Ox 催化剂表现出优异的活性，在 220°C 时 NOx 和 CB 的去除效率分别达到 94.5% 和 96%。此外，在注入 300 ppm SO2 和 7 vol% H2O 36 小时后，MnNb0.4Ce0.2Ox 的 NOx 和 CB 去除效率仍保持在 80% 以上。此外，CB和NOx+NH3的存在可以分别提高MnNb0.4Ce0.2Ox对NOx和CB的去除效率。N2-BET、Py-IR、H2-TPR和NH3-TPD的分析结果表明，Nb的引入增加了平均孔径、孔容和表面积，明显促进了路易斯酸量的增长，并增强 MnCe0.2Ox 在 100–250 °C 的氧化还原能力。此外，系统研究了 MnNb0.4Ce0.2Ox 催化剂上 NH3-SCR 和 CB 氧化反应中 NOx、NH3、CB 和 SO2 的分子迁移过程。原位 DRIFTS、FT-IR 和 XPS 还证实，在 SO2 和 H2O 存在下引入 Nb 可以有效抑制硫酸盐物质和 SO2 在 MnNb0.4Ce0.2Ox 表面的吸附。此外，由于 Mn、Nb 和 Ce 之间的相互作用，Nb 添加剂还增强了 MnNb0.4Ce0.2Ox 的结构稳定性。NH3-TPD、H2-TPR 和原位 DRIFTS 结果也证实 MnNb0.4Ce0.2Ox 在 SO2 和 H2O 存在下仍保留丰富的酸性位点和高氧化还原能力。总之，MnNb0.4Ce0.2Ox 催化剂代表了在低温下控制 NOx 和 CB 的有前途和有效的候选者。