Efficient catalytic removal of diesel soot over Mg substituted K/La0.8Ce0.2CoO3 perovskites with large surface areas
Efficient catalytic removal of diesel soot over Mg substituted K/La0.8Ce0.2CoO3 perovskites with large surface areas
复制标题
大表面积镁取代 K/La0.8Ce0.2CoO3 钙钛矿高效催化去除柴油机烟灰
DOI：
10.1016/j.cej.2016.02.038
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发表时间：
2016-06-01
影响因子：
15.1
通讯作者：
Guan, Guofeng
中科院分区：
文献类型：
--
作者：
Wang, Lei;Fang, Shuqing;Guan, Guofeng
采用改进的柠檬酸络合法制备了Mg取代的La0.8Ce0.2CoO3（LCCM）钙钛矿氧化物，其比表面积为148.7m2/g。然后，通过浸渍法制备了K促进的LCCM催化剂。采用XRD、FT-IR、N2吸附-脱附、SEM、TEM、XPS和TG/DTA等技术对样品进行了表征。Mg的加入不仅抑制了LCCM微晶的生长，而且抑制了纳米粒子的团聚，从而增加了LCCM钙钛矿的比表面积。Mg ~（2+）的低价取代促进了Co ~（4+）和吸附氧物种的形成，K ~+部分取代La ~（3+）则进一步促进了Co ~（4+）和吸附氧物种的形成。K促进提高了邻近碳中心的局域电子密度和与氧原子的结合亲和力，有利于碳烟与催化剂表面的接触，从而提高了催化剂的活性。在所有催化剂中，600 ℃焙烧的K/LCCM-4催化剂在380 ℃时的T-m、T-t活性最高，且稳定性较好，循环使用3次后的T-m、T-l仅增加10 ℃。2016爱思唯尔B. V.保留所有权利。
Mg-substituted La0.8Ce0.2CoO3 (LCCM) perovskite oxides with large surface areas (148.7 m(2)/g) were prepared by a modified citric acid complexation method. Then, K promoted LCCM catalysts were synthesized via impregnation. The samples were characterized by XRD, FT-IR, N-2 adsorption-desorption, SEM, TEM, XPS and TG/DTA techniques. The addition of Mg not only restrained the growth of LCCM crystallite, but also inhibited the agglomeration of nanoparticles and, consequently the surface areas of LCCM perovskites increased. The low-valence ion substitution of Mg2+ both promoted the formation of Co4+ and adsorbed oxygen species, which were further enhanced by the partial replacement of La3+ by K+. The local electron density of neighboring carbon sites and their affinity for binding oxygen atom were promoted by K promotion, which also contributed to the contact between soot and catalyst surface, and the activity of the catalyst was thus enhanced. Among all the catalysts, the K/LCCM-4 calcined at 600 degrees C exhibited the highest activity with T-m,T-t at 380 degrees C, and maintained good stability with T-m,T-l only increased by 10 degrees C after recycling for three times. 2016 Elsevier B.V. All rights reserved.