A series of Sm- and/or Zr-doped MnO_x-TiO₂ catalysts were prepared, and the catalysts exhibited better N₂ selectivity and SO₂ resistance than the undoped MnO_x-TiO₂ catalyst for the selective catalytic reduction of NO by NH₃ (NH₃-SCR). The reasons for the good N₂ selectivity and SO₂ resistance of the catalysts were proposed. X-ray photoelectron spectroscopy (XPS) combined with density functional theory (DFT) calculations suggested that electron transfer between the manganese and samarium species by Mn⁴⁺+Sm²⁺↔Mn³⁺+Sm³⁺ redox cycles occurred in the Sm-containing catalysts. Furthermore, electron transfer from Sm²⁺ to Mn⁴⁺ suppressed electron transfer from NH₃ to Mn⁴⁺, inhibiting the formation of NH₂ or NH. Thus, the pathway for NH generation was removed, and the reaction of 2NH+4NO→3N₂O+H₂O was prevented. Consequently, the N₂ selectivity of the NH₃-SCR reaction was enhanced. In situ diffused reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) combined with thermogravimetry, differential scanning calorimetry and mass spectrometry (TG-DSC-MS) results revealed that the deposition rate of sulfate species decreases after Sm doping, which was also attributed to the suppressed electron transfer from SO₂ to Mn⁴⁺, i.e., the oxidation of SO₂ to SO₃. Thus, the catalysts exhibited better SO₂ resistance.

制备了一系列掺Sm和/或Zr的MnO _x -TiO ₂催化剂，该催化剂与未掺杂的MnO _x -TiO ₂催化剂相比，对NH选择性催化还原NO具有更好的N ₂选择性和SO ₂耐受性。₃（NH ₃ -SCR）。提出了催化剂具有良好的N ₂选择性和抗SO ₂的原因。X射线光电子能谱（XPS）结合密度泛函理论（DFT）计算表明，Mn ⁴⁺ + Sm 2 ⁺ ↔Mn3 ⁺在锰和sa物种之间进行电子转移在含Sm的催化剂中发生+ Sm ³⁺氧化还原循环。此外，电子从Sm ²⁺转移到Mn ⁴⁺抑制了电子从NH ₃转移到Mn ⁴⁺，从而抑制了NH ₂或NH的形成。因此，消除了产生NH的途径，并防止了2NH + 4NO→3N ₂ O + H ₂ O的反应。因此，提高了NH ₃ -SCR反应的N ₂选择性。原位漫反射红外傅里叶变换光谱（原位DRIFTS）结合热重分析，差示扫描量热法和质谱（TG-DSC-MS）结果表明，Sm掺杂后硫酸盐物种的沉积速率降低，这也归因于电子从SO ₂转移到Mn ⁴⁺的抑制作用，即，将SO ₂氧化为SO ₃。因此，催化剂表现出更好的抗SO ₂性。