La_(1-x)Rb_xMnO_3钙钛矿催化剂同时消除NO和碳烟的催化性能

采用溶剂热法制备了La_(1-x)Rb_xM n O_3(x=0、0.1、0.2、0.3)钙钛矿型复合金属氧化物催化剂,通过XRD、FT-IR、SEM、XPS和H_2-TPR等手段对催化剂进行表征,在微型固定床反应器上评价了其同时消除NO和碳烟的催化性能。结果表明,La_(1-x)Rb_xM n O_3催化剂具有单一的钙钛矿结构,样品中Mn物种以Mn~(3+)和Mn~(4+)的形式存在。与LaMn O_3催化剂相比,Rb~+部分取代La~(3+),催化剂体系中形成较多的高价Mn~(4+)和氧空位,其氧化还原性能提高,催化性能得到改善。随着Rb~+取代量的增加,NO转化率升高,碳烟燃烧温度降低。当x=0.3时,La_(0.7)Rb_(0.3)M n O_3催化剂上CO_2浓度峰值温度t_(max)为430℃,CO_2的选择性为99.0%;反应温度为429℃,NO转化率达到最大,为59.7%。

Catalytic performance of La1-xRbxMnO3 perovskite in the simultaneous removal of NO and soot

A series of La_1-xRb_xMnO₃ perovskite catalysts (x=0, 0.1, 0.2, 0.3) were prepared by solvothermal method and characterized by means of XRD, FT-IR, SEM, XPS and H₂-TPR; their catalytic performance in the simultaneous removal of NO and soot was investigated in a fixed-bed micro-reactor. The results show that the La_1-xRb_xMnO₃ catalysts have a single perovskite structure and the Mn species exist in the form of Mn³⁺ and Mn⁴⁺. In comparison with LaMnO₃, when La³⁺ is partially substituted by Rb⁺, more high-valence Mn⁴⁺ and oxygen vacancies are formed in La_1-xRb_xMnO₃, which can improve the redox properties and enhance the catalytic performance of La_1-xRb_xMnO₃. With the increase of Rb⁺ content in La_1-xRb_xMnO₃, the conversion of NO increases and the soot combustion temperature decreases. For NO and soot removal over La_0.7Rb_0.3MnO₃,x=0.3, the peak CO₂ formation temperature (t_max) is 430 ℃, with a selectivity of 99.0% to CO₂; at 429 ℃, the maximum conversion of NO reaches 59.7%.