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开发了涂覆在金属丝网基体上的La_(0.8)Ca_(0.2)FeO_3/MgAl_2O_4复合整体催化剂,用于低浓度甲烷(0.5%,体积分数)催化燃烧反应.首先用沉积-沉淀法制备了La_(0.8)Ca_(0.2)FO_3(LCF)钙钛矿与Mg Al_2O_4尖晶石复合的粉末催化剂LCF/Mg Al2O4,用程序升温微反应器(TPRS)测定了粉末活性,结合XRD、BET、SEM、TPR的表征结果,筛选出了最佳复合物质的量比和最适焙烧温度.当LCF与Mg Al_2O_4复合后,抗烧结能力增强,以拟一级反应速率常数(k,L·g~(-1)·s~(-1))计的活性提高了1倍左右.然后采用浆料涂覆法,在表面改性的金属丝网蜂窝基体上分层涂覆了作为第二载体的MgAl_2O_4和LCF/Mg Al_2O_4复合粉体涂层,考察了复合粉体球磨前焙烧的温度、第二载体及活性层涂覆量的影响.最后在空速GHSV=40000 h~(-1)条件下测试了甲烷催化燃烧反应的活性.与陶瓷基体相比,涂覆在金属丝网基体上的LCF/MgAl_2O_4活性在600℃时提升了48.1%.500 h长运转试验发现,催化剂活性在初期的200 h下降了20.3%,然后基本保持稳定.
A La_ (0.8) Ca_ (0.2) FeO_3 / MgAl_2O_4 composite monolithic catalyst coated on a wire mesh substrate was developed for the catalytic combustion of methane with a low concentration of methane (0.5%) by first depositing and precipitating The activity of the powder was measured by temperature programmed microreactor (TPRS), and the effects of XRD, BET and SEM on the powder catalyst LCF / Mg Al2O4 with La 0.8 Co 0.2 O 3 (LCF) perovskite and Mg Al 2 O 4 spinel were investigated. , TPR characterization results, screening out the best ratio of the amount of composite material and the optimum calcination temperature.When LCF and Mg Al 2 O 4 complex, the anti-sintering ability to enhance the quasi-first-order reaction rate constant (k, L · g ~ -1) · s ~ (-1)) activity was increased by about 1 time.And then using the slurry coating method, the modified surface of the wire mesh honeycomb substrate was layered as a second carrier MgAl_2O_4 And the coating of LCF / Mg Al 2 O 4 composite powders were investigated.The effects of the calcination temperature, the second support and the coating amount of the active layer before and after milling were investigated.Finally, the test was performed under a space velocity of GHSV = 40000 h -1 The activity of methane catalytic combustion reaction.Compared with the ceramic matrix, the LCF / MgAl 2 O 4 activity coated on the metal mesh substrate increased by 48 at 600 ℃ .1% .500 h long run test found that the catalyst activity decreased 20.3% in the initial 200 h, and then remained basically stable.