共沉淀法和浸渍法制备的HoCeMn/TiO2催化剂的脱硝性能

采用浸渍法和共沉淀法制备了HoCeMn/TiO₂脱硝催化剂并对其结构和性能进行了表征。结果表明共沉淀法增强了活性组分和载体的相互作用，从而增加了 HoCeMnTi-C催化剂表面 Ce³⁺、Mn⁴⁺以及吸附氧的含量，使其表现出优异的低温氧化还原性能。此外，共沉淀法制备的HoCeMnTi-C具有更多的表面酸性位点及更强的表面酸性。催化剂表面酸性和氧化还原性能的提高有助于氨的吸附和活化，从而显著提高其活性。表面酸性位点的增多还抑制了 H₂O和 SO₂在催化剂表面的吸附，提升了催化剂的抗水抗硫性能。催化剂上的选择性催化还原(SCR)反应遵循Eley-Rideal(E-R)机制，催化剂硫中毒是源于形成的硫酸盐覆盖或破坏了催化剂活性位。

Denitration performance of HoCeMn/TiO2 catalysts prepared by co-precipitation and impregnation methods

Impregnation and co-precipitation methods were used to synthesize HoCeMn/TiO₂ catalysts for the reduction of NO_x with NH₃. Different kinds of characterization methods were used to explore the structures and performances of the catalysts. The results show that the co-precipitation method enhances the interactivity between the active component and carrier, thereby increasing the content of Ce³⁺, Mn⁴⁺, and adsorption oxygen on the surface of HoCeMnTi-C. As a result, it showed excellent low-temperature redox performance. In addition, HoCeMnTi-C prepared by the co-precipitation method possessed more surface acidic sites and stronger surface acidity. The improvement of surface acidity and redox performance is conducive to the adsorption and activation of ammonia, and there-by significantly improved its activity. The increase of acidic sites also restrained the adsorption of H₂O and SO₂, and therefore sulfur and water resistance of HoCeMnTi-C were significantly promoted. The reaction of selective catalytic reduction (SCR) on catalysts obeys the Eley-Rideal (E-R) mechanism. SO₂ poisoning of catalysts was caused by the formation of sulfates, which cover or damage the active sites of the catalysts.