Manganese (Mn)-based mixed oxides are considered the most efficient catalysts for low-temperature ammonia selective catalytic reduction of nitrogen oxides (NO_x) (NH₃-SCR of NO_x). Water resistance and sulfur tolerance, especially the SO₂ tolerance of Mn-based catalysts, are the main obstacles preventing their practical application. Therefore, in this study, a series of cobalt (Co)-doped MnFeO_x ternary mixed oxides catalysts with a hierarchically ordered structure (Hierc-MnFe_1-δCo_δO_x, δ = 0.2, 0.4 and 0.6) were developed and applied for NH₃-SCR of NO_x at low temperature. Compared with Hierc-MnFeO_x, Hierc-MnFe_1-δCo_δO_x catalyst exhibited enhanced low-temperature activity and a broadened temperature window (NO_x conversion above 80% was between 90 and 343 °C over Hierc-MnFe_0.6Co_0.4O_x), as well as better H₂O resistance and SO₂ tolerance. The enhanced low-temperature activity was attributed to a larger amount of active oxygen species, a higher proportion of Mn⁴⁺, Fe³⁺ and Co³⁺ content, and the improvement of surface acidity, which can facilitate the adsorption and activation of NO and NH₃. Additionally, the Hierc-MnFe_0.6Co_0.4O_x catalyst exhibited superior soot tolerance due to its special hierarchically ordered architecture. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed that the Co-modified Hierc-MnFe_1-δCo_δO_x ternary oxide catalyst could efficiently protect nitrate species on Hierc-MnFe_0.6Co_0.4O_x from the poisoning effect of SO₂, thereby boosting its SO₂ tolerance. This study provides a good candidate for low-temperature deNO_x application with enhanced SO₂ and soot tolerance.

锰（Mn）基混合氧化物被认为是低温氨选择性催化还原氮氧化物（NO的最有效的催化剂_X）（NH ₃ -SCR NO的_X）。耐水性和耐硫性，特别是Mn基催化剂的SO ₂耐性是阻碍其实际应用的主要障碍。因此，在该研究中，一系列钴（Co） -掺杂的MnFeO _X三元具有层次有序结构的混合氧化物的催化剂（Hierc-锰铁_1-δ钴_δ ø _X，δ= 0.2，0.4和0.6）进行了开发和应用对于NH ₃ -SCR的NO _x在低温下。与Hierc-MnFeO相比_X，Hierc-锰铁_1-δ钴_δ ø _X催化剂表现出增强的低温活性和加宽的温度窗口（NO _X转化率在80％以上为90和343℃之间在Hierc-锰铁_0.6钴_0.4 O _x），以及更好的H ₂ O耐受性和SO ₂耐受性。增强的低温活性归因于大量的活性氧，较高比例的Mn ⁴⁺，Fe ³⁺和Co ³⁺含量和表面酸性的改善，这可以促进NO和NH ₃的吸附和活化。另外，Hierc-MnFe _0.6 Co _0.4 O _x催化剂由于其特殊的分级有序结构而显示出优异的烟尘耐受性。原位漫反射红外线傅里叶变换光谱法（DRIFTS）分析表明共改性Hierc-锰铁_1-δ钴_δ ø _X三元氧化物催化剂可以在Hierc-锰铁有效地保护硝酸盐物种_0.6钴_0.4 ø _X从SO的中毒效果₂，从而提高其SO ₂公差。这项研究为低温脱硝_x的应用提供了一个很好的候选者，它具有增强的SO ₂和烟灰耐受性。