La1-xKxMnO3催化剂同时消除柴油机尾气中NO和碳烟性能

采用溶剂热法制备La_1-xK_xMnO₃(x=0, 0.10, 0.15, 0.20, 0.25)钙钛矿型复合金属氧化物催化剂;通过XRD、FT-IR、SEM、H₂-TPR、XPS、NO-TPD等手段对催化剂的物相组成、表面形貌、氧化还原性能等进行了表征;在常压固定床微型反应装置中评价催化剂同时消除NO和碳烟催化性能.结果表明,制备的La_1-xK_xMnO₃催化剂均具有钙钛矿结构;K部分取代La-Mn钙钛矿结构中La后,颗粒结构得以改善,部分Mn³⁺价态升高为Mn⁴⁺,形成较多氧空位和Mn⁴⁺,提高氧化还原性能和吸附NO性能.活性评价结果表明,La_0.80K_0.20MnO₃催化剂表现出较好的同时消除NO和碳烟催化性能,NO最大转化率(Xmax NO)和对应反应温度(Tmax NO)分别为46.5%和436℃,碳烟起燃温度(T_ig)、CO₂浓度峰值温度(Tmax CO₂)和生成CO₂选择性(Smax CO₂)分别为341℃、454℃和98.8%.

Simultaneous removal of NO and soot from diesel engines over La1-xKxMnO3 catalysts

La_1-xk_xMnO₃ (x=0, 0.10, 0.15, 0.20, 0.25) perovskite oxide catalysts were prepared by solvothermal method. Various methods such as XRD, FT-IR, SEM, H₂-TPR, XPS and NO-TPD, were used to characterize structure, composition, surface morphology, and the redox properties of the catalysts. Their catalytic performance of the simultaneous NO and soot removal was investigated in a fixed-bed micro-reactor under atmospheric pressure. The results indicated that the La_1-xK_xMnO₃ catalysts showed perovskite structure. For La_1-xK_xMnO₃ catalysts, with the partial substitution of La³⁺ by K⁺ in the Mn-based perovskite lattice, a portion of Mn³⁺ was transformed into Mn⁴⁺ and the number of oxygen vacancies was increased, leading to an improvement of the redox properties and NO adsorption performance. As a result, the catalytic reactivity of La_0.80K_0.20MnO₃ catalyst was also improved, achieving the simultaneous removal of NO and soot. The maximum conversion of NO (Xmax NO) and the reaction temperature (T_max) were 46.5% and 436 ℃, respectively. The ignition temperature of soot (T_ig), peak CO₂ formation temperature (Tmax CO₂) and CO₂ selectivity (Smax CO₂) were 341℃, 454℃ and 98.8%, respectively.