低温等离子体改性LaCoO3催化剂去除炭烟颗粒的催化性能

摘要

采用低温等离子体对LaCoO3复合氧化物进行表面改性,利用XRD、FT-IR、H2-TPR和O2-TPD等对催化剂表面物化性能进行表征,分析等离子体对催化剂表面物化性质的影响.采用程序升温氧化反应评价催化剂对模拟柴油机炭烟催化氧化的活性.结果表明,等离子体改性促进了催化剂表面晶格氧的活化,增加了活性氧物种数目,从而增强了催化剂对炭烟催化氧化活性,炭烟催化起燃温度Ti由278℃降到274℃,峰值温度Tm由354℃降至345℃,燃尽温度Tf由425℃降至386℃.%LaCoO3 composite oxides were modified by low temperature plasma. The physicochemical properties of the catalyst surface were characterized by means of XRD, H2-TPR, O2-TPD, FT-IR to analyze effect of plasma on surface character of the catalyst. Catalytic activities of the catalyst for oxidation of simulated diesel soot were evaluated by temperature-programmed oxidation reaction. The experimental results showed that plasma modification promoted activation of lattice oxygen on the surface of the catalyst, increased the number of reactive oxygen species, and enhanced the catalytic oxidation activity of the catalyst for soot removal. The ignition temperature Tidecreased from 278 ℃ to 274 ℃, the peak temperature Tmreduced from 354 ℃ to 345 ℃ and the finishing combustion temperature Tfreduced from 425 ℃to 386 ℃.