Manganese-based catalysts are considered as ideal alternative catalysts for NH₃ selective catalytic reduction of NO_x due to their excellent denitrification performance, but their weak water resistance limits industrial applications. To improve the water resistance of low-temperature Mn-based catalysts in the NH₃-SCR reaction, a Ti-OMS-2 (titanium-manganese oxide octahedral molecular sieve) catalyst was prepared by the hydrothermal method, and polytetrafluoroethylene (PTFE) powder was methodically introduced on the catalyst surface by the impregnation method. Importantly, the introduction of PTFE on the Ti-OMS-2 catalyst surface could effectively inhibit the adsorption of water molecules and reduce the probability of active species being consumed. Thus, it showed better catalytic activity and water resistance. The activity of the Ti-OMS-2-20%-PTFE catalyst could reach more than 80% when water vapor was introduced at 180 °C. More importantly, the Ti-OMS-2-20%-PTFE catalyst did not readily bind the active species (Mn⁴⁺ and O_ads) and maintained the adsorption and activation of NH₃ species. Moreover, it was easy for PTFE to form a weak surface hydrophobic layer on the Ti-OMS-2 catalyst surface that could effectively inhibit water toxicity. Therefore, this work provided a reasonable idea and experimental accumulation for the industrial application of Mn-based catalysts.

中文翻译：

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提高用于低温 NH3-SCR 反应的 PTFE 改性 Ti-OMS-2 催化剂的耐水能力

锰基催化剂以其优异的脱硝性能被认为是NH ₃选择性催化还原NO _x的理想替代催化剂，但其较弱的耐水性限制了工业应用。提高低温锰基催化剂在NH _{3中的耐水性}-SCR反应，采用水热法制备Ti-OMS-2（钛锰氧化物八面体分子筛）催化剂，并采用浸渍法有条不紊地将聚四氟乙烯（PTFE）粉末引入催化剂表面。重要的是，在Ti-OMS-2催化剂表面引入PTFE可以有效抑制水分子的吸附，降低活性物质被消耗的概率。因此，它表现出更好的催化活性和耐水性。Ti-OMS-2-20%-PTFE催化剂在180℃通入水蒸气时活性可达80%以上。更重要的是，Ti-OMS-2-20%-PTFE催化剂不易与活性物质（Mn ⁴⁺和O _{ads ）结合，维持了对NH 3}的吸附和活化物种。此外，PTFE易于在Ti-OMS-2催化剂表面形成弱表面疏水层，可有效抑制水毒性。因此，该工作为锰基催化剂的工业化应用提供了合理的思路和实验积累。