• 关键词：甲烷催化燃烧  La_0.8Ca_0.2FeO₃钙钛矿  MgAl₂O₄尖晶石  复合催化剂  丝网整体催化剂

• 基金项目：

• 段伟杰
• 上海交通大学化学化工学院, 上海市绝缘与老化重点实验室, 上海 200240

• 李怀有
• 上海交通大学化学化工学院, 上海市绝缘与老化重点实验室, 上海 200240

• 王忍青
• 上海交通大学化学化工学院, 上海市绝缘与老化重点实验室, 上海 200240

• 王强
• 上海交通大学化学化工学院, 上海市绝缘与老化重点实验室, 上海 200240

• 江志东
• 上海交通大学化学化工学院, 上海市绝缘与老化重点实验室, 上海 200240

• 摘要：开发了涂覆在金属丝网基体上的La_0.8Ca_0.2FeO₃/MgAl₂O₄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_0.8Ca_0.2FeO₃（LCF）钙钛矿与MgAl₂O₄尖晶石复合的粉末催化剂LCF/MgAl₂O₄，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MgAl₂O₄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MgAl₂O₄和LCF/MgAl₂O₄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/MgAl₂O₄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.

• Abstract：The honeycomb catalysts of La_0.8Ca_0.2FeO₃/MgAl₂O₄ were developed by washcoating the composite powders of La_0.8Ca_0.2FeO₃(LCF) perovskite and MgAl₂O₄ spinel onto the honeycomb substrates fabricated with the metallic wire mesh and applied for catalytic combustion of air diluted methane (0.5%). First, the composite powders of LCF/MgAl₂O₄ were prepared by deposition-precipitation method. The activity of the composite powder was measured in the Temperature-Programmed Micro Reactor (TPRS) and the properties were characterized by XRD, BET, SEM, and TPR in an effort to optimize the molar ratio of LCF to MgAl₂O₄ and the proper calcination temperature of the composite. It was found that after compositing with MgAl₂O₄, the thermal resistance of LCF was improved substantially, and its activity quantified by the pseudo-first-order reaction rate constant (k, L·g^-1·s^-1) almost doubled. Afterwards, the wire-mesh honeycomb substrate modules were dip-coated sequentially by slurries of MgAl₂O₄ and LCF/MgAl₂O₄ composite powders, respectively. Influences of the calcination temperature of the composite powder before ball-milling and loadings of MgAl₂O₄ and composite powder coatings were investigated. For comparison, the catalytic combustion of 0.5% methane was carried out at GHSV of 40000 h^-1 for both wire-mesh and ceramic honeycomb catalysts, where the activity of the catalyst on wire-mesh substrate was 48.1% higher at 600℃. Finally, the performance of the wire-mesh honeycomb was examined in a time-on-stream test for 500 hours. The activity was dropped by 20.3% in the initial 200 hours, and then stablized for the remaining 300 hours.

• Key words：catalytic combustion of methane  La_0.8Ca_0.2FeO₃ perovskite  MgAl₂O₄ spinel  composite catalyst  wire-mesh honeycomb

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