载体物化性质对锰铈催化剂NH3-SCR脱硝性能的影响

选取TiO₂、SAPO-34、Al₂O₃三种常用载体，通过浸渍法以Mn-Ce-O为活性组分制备了负载型MnCeO_x脱硝催化剂。采用XRD、BET、H₂-TPR、XPS、Py-FTIR等手段对催化剂的固相结构、比表面积、还原性能、表面元素及酸量进行表征分析。结果表明，MnCeO_x/SAPO-34催化剂具有最大的比表面积（439.87 m²/g），酸量适中，还原性能最差；MnCeO_x/Al₂O₃催化剂中Mn⁴⁺、Ce³⁺所占比例较高，但酸性最弱；MnCeO_x/TiO₂催化剂还原性能最优，表面Mn、Ce元素浓度最高，并具有大量Lewis酸性位。通过气固相催化反应装置对催化剂性能进行了NH₃-SCR脱硝评价，结果表明，MnCeO_x/TiO₂催化剂具有较好的脱硝性能，反应温度为280 ℃时，NO转化率达100%（空速为42000 h^-1）；与催化剂物化性质对比分析，催化剂的氧化还原能力和Lewis酸性位对其脱硝性能至关重要。

Influence of different supports on the physicochemical properties and denitration performance of the supported MnCe-based catalysts for NH3-SCR

A series of supported Mn-Ce-based catalysts were prepared using TiO₂, SAPO-34, and Al₂O₃ as supports. The physicochemical properties of the obtained catalysts, such as structure, specific surface area, reduction properties, surface elements and acidity were characterized with XRD, BET, H₂-TPR, XPS and Py-FTIR. The results showed that MnCeO_x/SAPO-34 catalyst exhibited a larger specific surface area (439.87 m²/g), medium amount of Lewis acid sites and the weakest reduction property. In the MnCeO_x/Al₂O₃ catalyst, the concentration of Mn⁴⁺ and Ce³⁺ was relatively high, and the amount of acid sites is the lowest. However, TiO₂ as the catalyst support could enhance the reduction property, and increase the amount of Lewis acid sites and the concentration of Mn and Ce. NH₃-SCR performances of the catalysts were evaluated using a flow type fixed bed reactor. The results showed that MnCeO_x/TiO₂ catalyst presented the best catalytic performance, over which near 100% NO conversion was reached at 280 ℃ under a gas hourly space velocity of 42000 h^-1. The combination of characterization and reaction results indicated that the good reduction behavior and large amount of Lewis acid sites were beneficial to the enhancement of the catalytic performance for low-temperature NH₃-SCR reaction.