Abstract：
The deactivation of selective catalytic reduction (SCR) catalysts caused by alkali metal poisoning remains an insurmountable challenge. In this study, we examined the impact of Na poisoning on the performance of Fe and Mo co-doped TiO2 (FeaMobTiOx) catalysts in the SCR reaction and revealed the related alkali resistance mechanism. On the obtained Fe1Mo2.6TiOx catalyst, the synergistic catalytic effect of uniformly dispersed FeOx and MoOx species leads to remarkable catalytic activity, with over 90% NO conversion achieved in a wide temperature range of 210-410 °C. During the Na poisoning process, Na ions predominantly adsorb on the MoOx species, which exhibit stronger alkali resistance, effectively safeguarding the FeOx species. This preferential adsorption minimizes the negative effect of Na poisoning on Fe1Mo2.6TiOx. Moreover, Na poisoning has little influence on the Eley-Rideal reaction pathway involving adsorbed NHx reacting with gaseous NOx. After Na poisoning, the Lewis acid sites were deteriorated, while the abundant Brønsted acid sites ensured sufficient NHx adsorption. As a benefit from the self-defense effects of active MoOx species for alkali capture, FeaMobTiOx exhibits exceptional alkali resistance in the SCR reaction. This research provides valuable insights for the design of highly efficient and alkali-resistant SCR catalysts.
摘要：
由碱金属中毒引起的选择性催化还原（SCR）催化剂的失活仍然是一个无法克服的挑战。在这项研究中,我们研究了Na中毒对SCR反应中Fe和Mo共掺杂TiO2（FeaMobTiOx）催化剂性能的影响，并揭示了相关的耐碱机理。在获得的Fe1Mo2.6TiOx催化剂上，均匀分散的FeOx和MoOx物种的协同催化作用导致显著的催化活性，在210-410°C的宽温度范围内实现90%以上的NO转化率。在钠中毒过程中，Na离子主要吸附在MoOx物种上，表现出更强的耐碱性，有效保护FeOx物种。这种优先吸附使Na中毒对Fe1Mo2.6TiOx的负面影响最小化。此外，Na中毒对涉及吸附的NHx与气态NOx反应的Eley-Rideal反应途径影响很小。Na中毒后,路易斯酸位点恶化了，而丰富的布朗斯台德酸位点确保了足够的NHx吸附。从活性MoOx物种用于碱捕获的自卫作用中受益，FeaMobTiOx在SCR反应中表现出优异的耐碱性。该研究为高效耐碱SCR催化剂的设计提供了有价值的见解。
