Novel Co- or Ni-Mn binary oxide catalysts with hydroxyl groups for NH3-SCR of NOx at low temperature

作者：Gao, Fengyu; Tang, Xiaolong^*; Yi, Honghong; Zhao, Shunzheng; Wang, Jiangen; Shi, Yiran; Meng, Xiaomi

来源：Applied Surface Science, 2018, 443: 103-113.

DOI：10.1016/j.apsusc.2018.02.151

• Low-temperature SCR
• Hydroxyl
• Mn-based catalysts
• NH4NO3
• N(2)selectivity
• Mn-O bond energy

Novel hydroxyl-containing Me-Mn binary oxides (Me = Co, Ni) were prepared for the selective catalytic reduction of NOx with NH3 by a combined complexation-esterification method. The binary oxides of Co-MnOx and Ni-MnOx with mixed crystal phases of Mn3O4 and Co3O4, Mn2O3 and NiMnO3 were obtained at 550 degrees C. SCR activity decreased in the order of Mn3O4-Co3O4-OH > Mn2O3-NiMnO3-OH > Mn2O3-OH > Mn3O4-OH, benefiting from the high concentration of chemisorbed oxygen and effective electron transformation of cations. Mn2O3-containing catalysts had better selectivity to N-2 than those containing Mn3O4. Higher selectivity to N2O over Mn3O4-containing catalysts was attributed to the depth dehydrogenation of coordinated NH3 by the active oxygen species with lower MnAO band energy. The typical Eley-Rideal mechanism over Mn3O4-OH and Mn3O4-Co3O4-OH, and the additional formation pathway of NH4NO3 species over Mn2O3-OH and Mn2O3-NiMnO3-OH catalysts were proposed via the in-situ DRIFTS experiments. Although the Co and Ni elements had a good role in delaying the poisoning of SO2, these catalysts were eventually sulfated by SO2 over the postponement, which might due to the metal sulfate and ammonia hydrogensulfite species.

• 出版日期2018-6-15
• 单位北京科技大学