Highly efficient multifunctional dually-substituted perovskite catalysts La_{1鈭?span style='font-style: italic'>x}K_xCo_{1鈭?span style='font-style: italic'>y}Cu_yO_{3鈭?span style='font-style: italic'>未} u

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• 作者：Zhaoqiang Li^a ; Ming Meng^a ; ^{mengm@tju.edu.cn} ; Yuqing Zha^a ; Fangfang Dai^a ; Tiandou Hu^b ; Yaning Xie^b ; Jing Zhang^b
• 关键词：Soot combustion ; NOx reduction ; Perovskite ; Dual substitution ; Mechanism
• 刊名：Applied Catalysis B ; Environmental
• 出版年：2012
• 期刊代码：4_09263373
• 类别：ce
• 出版时间：13 June, 2012
• 卷：121-122
• 期：Complete
• 页码：65-74
• 文件大小：1245 K

摘要

A series of K/Cu simultaneously substituted nanometric perovskite catalysts La_1鈭?em>xK_xCo_1鈭?em>yCu_yO_3鈭?em>未 (x = 0, 0.1; y = 0, 0.05, 0.1, 0.2, 0.3) were synthesized by citric acid complexation, which were employed for soot combustion, NOx storage and simultaneous NOx-soot removal. The physico-chemical properties of the catalysts were characterized by XRD, FT-IR, EXAFS, SEM, H₂-TPR, Soot-TPR, TG/DTA, XPS and in situ DRIFTS techniques. When K and Cu are simultaneously introduced into LaCoO₃, soot combustion is largely accelerated, decreasing the characteristic temperature (T_m) corresponding to the maximal soot combustion rate at least 80 掳C; moreover, NOx reduction by soot is also remarkably facilitated. Among all the catalysts La_0.9K_0.1Co_0.9Cu_0.1O_3鈭?em>未 shows the lowest T_m of 360 掳C, the highest NOx storage capacity (NSC) of 284 渭mol g^鈭? and the largest NOx reduction percentage of 32%; for soot combustion, it also exhibits the lowest activation energy (80.04 kJ mol^鈭?). The XPS and Soot-TPR results reveal that the catalyst La_0.9K_0.1Co_0.9Cu_0.1O_3鈭?em>未 possesses more active and larger amount of surface oxygen species (O₂^{鈭?/sup> and O鈭?/sup>), more tetravalent cobalt ions and better reducibility than others, which determines its better catalytic performance. Based on in situ DRIFTS and other characterization results, the potential mechanisms for soot combustion, NOx storage and simultaneous NOx-soot removal are proposed.}