The 30CeO₂-4WO₃/TiO₂ catalyst was prepared utilizing cost-effective cerium chloride instead of the traditional cerium nitrate as the cerium source in this paper. The structure, physical and chemical properties, catalytic performance were characterized. The catalytic performance and N₂ selectivity of the 30CeO₂-4WO₃/TiO₂ catalyst significantly deteriorate with increased the content of Cl^-. Specifically, denitration efficiency of 30CeO₂-4WO₃/TiO₂-0.007 % exceeding 80 % and 90 % were 225 ∼ 520 °C and 241 ∼ 504 °C, respectively, whereas the maximum denitration efficiency of the 30CeO₂-4WO₃/TiO₂-0.161 % sample was only 79.83 %. The effect mechanism of Cl^- on catalytic performance was discussed. (1) XRD and BET results show that Cl^- can cause the expansion of the lattice of TiO₂ and CeO₂, thereby increasing its crystallinity and decreasing the specific surface area. (2) Cl^- interacts with NH₄⁺ to form NH₄Cl, which subsequently reacts with CeO₂ to produce CeOCl, leading to the obstruction of the catalyst’s micropores. (3) XPS, NH₃-TPD, and H₂-TPR analyses reveal that Cl^- would occupy the oxygen vacancies, impeding oxygen migration and diminishing active surface centers. (4) In-situ DRIFTs analysis demonstrates that elevated Cl^- concentrations diminish NH₃ adsorption capacity and facilitate nitrate species formation. The accumulation of nitrates was a primary cause of the decline in catalyst activity.

中文翻译：

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Cl- 对 CeO2-WO3/TiO2 催化剂对 NH3 选择性催化还原 NO 的影响


本文采用经济高效的氯化铈代替传统的硝酸铈作为铈源，制备了 30CeO ₂ -4WO ₃ /TiO ₂ 催化剂。对结构、理化性质、催化性能进行了表征。30CeO ₂ -4WO ₃ /TiO ₂ 催化剂的催化性能和 N ₂ 选择性随着 Cl 含量的增加而显著变差 ^- 。具体而言，30CeO ₂ -4WO ₃ /TiO ₂ -0.007 % 超过 80 % 和 90 % 的脱硝效率分别为 225 ∼ 520 °C 和 241 ∼ 504 °C，而 30CeO ₂ -4WO ₃ /TiO ₂ -0.161 % 样品的最大脱硝效率仅为 79.83 %。讨论了 Cl ^- 对催化性能的影响机制。（1） XRD 和 BET 结果表明，Cl ^- 可以引起 TiO ₂ 和 CeO ₂ 晶格的膨胀，从而提高其结晶度，降低比表面积。（2） Cl 与 NH ^- ₄ 作用 ⁺ 形成 NH ₄ Cl，随后与 CeO ₂ 反应生成 CeOCl，导致催化剂的微孔堵塞。（3） XPS、NH ₃ -TPD 和 H ₂ -TPR 分析表明，Cl ^- 会占据氧空位，阻碍氧迁移并减小活性表面中心。（4） 原位 DRIFTs 分析表明，升高的 Cl ^- 浓度会降低 NH ₃ 吸附能力并促进硝酸盐物种的形成。硝酸盐的积累是催化剂活性下降的主要原因。