The mullite SmMn₂O₅ (SMO) was modified with silver for soot oxidation by two methods, i.e. sol-gel (Ag/SMO-sg) and impregnation (Ag/SMO-im). The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma atomic emission spectrometry (ICP-AES), H₂-O₂ titration, H₂ temperature-programmed reduction (H₂-TPR), CO temperature-programmed reduction (CO-TPR), soot temperature-programmed reduction (soot-TPR), O₂ temperature-programmed desorption (O₂-TPD), cycled H₂ temperature-programmed reduction (cycled H₂-TPR), NO temperature-programmed oxidation (NO-TPO) and soot temperature-programmed oxidation (soot-TPO). Metallic silver nanoparticles were observed in the mullite matrix for both the catalysts. For Ag/SMO-sg, the possible incorporation of silver into the mullite crystal cell and strong electronic interaction between the highly dispersed metal and the support increase the Mn⁴⁺/Mn³⁺ ratio and create more structural defects in the mullite, resulting in boosted NO oxidation and thereby NO₂-assisted soot combustion. The introduction of Ag can promote the generation/regeneration of active oxygen, which accelerates the ignition of soot in O₂ at low temperatures. Therefore, the sol-gel-synthesized Ag/SmMn₂O₅ is highly promising for application in diesel particulate filters.

用银对莫来石SmMn ₂ O ₅（SMO）进行银改性，以通过两种方法进行烟灰氧化，即溶胶-凝胶（Ag / SMO-sg）和浸渍（Ag / SMO-im）。通过X射线衍射（XRD），Brunauer-Emmett-Teller（BET），透射电子显微镜（TEM），X射线光电子能谱（XPS），电感耦合等离子体原子发射光谱法（ICP-AES）对催化剂进行了表征H ₂ -O ₂滴定，H _2程序升温还原（H ₂ -TPR），CO程序升温还原（CO-TPR），烟灰程序升温还原（soot-TPR），O _2程序升温脱附（O ₂ -TPD），循环H ₂程序升温还原（循环H ₂ -TPR），NO程序升温氧化（NO-TPO）和烟灰程序升温氧化（soot-TPO）。在两种催化剂的莫来石基质中均观察到金属银纳米颗粒。对于Ag / SMO-sg，可能将银掺入莫来石晶体电池中，以及高度分散的金属与载体之间的强电子相互作用会增加Mn ⁴⁺ / Mn ³⁺比率，并在莫来石中产生更多的结构缺陷，从而导致促进了NO氧化，从而促进了NO ₂辅助的烟灰燃烧。Ag的引入可以促进活性氧的生成/再生，从而加速O ₂中烟灰的点燃。在低温下。因此，溶胶-凝胶合成的Ag / SmMn ₂ O ₅具有很高的应用前景。