三维有序大孔La_(1-x)K_(x)Ni_(0.8)Co_(0.2)O_(3)钙钛矿对柴油发动机碳烟的氧化研究

Study on oxidation of diesel engine soot by 3DOM La_(1-x)K_(x)Ni_(0.8)Co_(0.2)O_(3) perovskite

本文采用胶体晶体模板法制备了钙钛矿型La_(1-x)K_(x)Ni_(0.8)Co_(0.2)O_(3)三维有序大孔(3DOM)结构催化剂,通过程序升温氧化测试了其对碳烟的催化氧化活性,并以多种物理化学手段探讨了结构与性能的关系。结果表明,3DOM La_(1-x)K_(x)Ni_(0.8)Co_(0.2)O_(3)催化剂具有显著的碳烟催化低温燃烧活性。其中,3DOM La_(0.85)K_(0.15)Ni_(0.8)Co_(0.2)O_(3)催化剂对碳烟催化燃烧反应的催化活性较高,其T_(10)、T_(50)和T_(90)分别低至298℃、370℃和442℃,SCO_(2)达到99.6%以上。K^(+)离子的掺入,使B位Ni和Co离子的价态升高,有利于O_(2)^(-)/-OH活性氧物种的生成。3DOM La_(1-x)K_(x)Ni_(0.8)Co_(0.2)O_(3)催化剂的大孔结构及掺入K^(+)后表面O_(2)^(-)/-OH活性氧物种的生成,促进了碳烟催化燃烧低温反应活性的增加。

In this paper,a perovskite-type La_(1-x)K_(x)Ni_(0.8)Co_(0.2)O_(3) catalysts with three-dimensional ordered macropore(3DOM)was prepared by the colloidal crystal template method,and its catalytic oxidation activity on soot was tested by temperature-programmed oxidation.In addition,the relationship between structure and performance was explored by various physical and chemical methods.The results showed that the 3DOM La_(1-x)K_(x)Ni_(0.8)Co_(0.2)O_(3) catalyst had significant low-temperature catalytic activity of soot combustion.Among them,the La_(0.85)K_(0.15)Ni_(0.8)Co_(0.2)O_(3) catalyst had a higher catalytic activity for the soot catalytic combustion reaction,which T_(10),T_(50) and T_(90) were as low as 298℃,370℃and 442℃,respectively,and SCO_(2) reached more than 99.6%.The incorporation of K^(+) ions increased the valence states of Ni and Co ions at the B site,and facilitated the generation of O_(2)^(-)/-OH active oxygen species.The macroporous structure of the 3DOM La_(1-x)K_(x)Ni_(0.8)Co_(0.2)O_(3) catalysts and the formation of O_(2)^(-)/-OH active oxygen species on the surface after incorporating K^(+) promote the increase of the low-temperature reaction activity of soot catalytic combustion.