Shen Zhenghua, Xing Xiangdong, Wang Sunxuan, Lv Ming, Li Jinke, Li Tao
School of Metallurgy Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi 710055, P. R. China.
Shaanxi Institute for Food and Drug Control, Xi'an 710065, P. R. China.
ACS Omega. 2022 Mar 4;7(10):8798-8807. doi: 10.1021/acsomega.1c07076. eCollection 2022 Mar 15.
To clarify the K modified effects over activated carbon (AC) supported Mn-Ce oxide catalysts, several Mn-Ce/AC and K-Mn-Ce/AC mixed oxide catalysts prepared via an impregnation method supported on AC were investigated for low-temperature selective catalytic reduction (SCR) of NO with NH in the simulated sintering flue gas. The Mn-Ce/AC catalyst with a K loading of 8% showed the highest catalytic activity, corresponding to 92.1% NO conversion and 92.5% N selectivity at 225 °C with a space velocity of 12,000 h. Furthermore, the 0.08K-Mn-Ce/AC catalyst exhibited better resistance to SO and HO than Mn-Ce/AC, which could convert 72.3% and 74.1% of NO at the presence of 5% SO and HO, respectively. After K modification, the relative ratios of Mn/Mn as well as Ce/Ce and surface adsorbed oxygen increased. Additionally, the reduction performance of the catalyst was improved obviously, and both acid strength and quantity of acid sites increased significantly after the K species were introduced in Mn-Ce/AC. Especially, the NO adsorption capacity of the catalyst was enhanced, which remarkably promoted the denitration efficiency and SO resistance. The SCR of NO with NH on K-Mn-Ce/AC catalysts followed the L-H mechanism.
为阐明钾（K）对活性炭（AC）负载的锰铈氧化物催化剂的改性作用，研究了通过浸渍法制备的几种负载在AC上的锰铈/AC和钾-锰铈/AC混合氧化物催化剂，用于模拟烧结烟气中NH₃选择性催化还原（SCR）NO。钾负载量为8%的锰铈/AC催化剂表现出最高的催化活性，在225℃、空速为12000 h⁻¹时，NO转化率为92.1%，N₂选择性为92.5%。此外，0.08K-锰铈/AC催化剂对SO₂和H₂O的抗性比锰铈/AC更好，在存在5% SO₂和H₂O的情况下，分别能将72.3%和74.1%的NO转化。钾改性后，Mn⁴⁺/Mn³⁺以及Ce⁴⁺/Ce³⁺的相对比例和表面吸附氧增加。此外，催化剂的还原性能明显提高，在锰铈/AC中引入钾物种后，酸强度和酸量均显著增加。特别是，催化剂的NO吸附能力增强，显著提高了脱硝效率和抗SO₂性能。钾-锰铈/AC催化剂上NH₃选择性催化还原NO遵循L-H机理。
