摘要
为构筑高效纸型催化剂用于碳烟消除,如何设计不同活性基元并实现与基体纤维的协同效应非常重要。通过静电纺丝法制备了一系列La_(1-x)K_(x)MnO_(3)(x=0、0.1、0.2、0.3、0.4、0.5)纳米纤维催化剂,并以其为基元制备了纸型催化剂用于碳烟催化消除。采用X射线衍射仪、扫描电子显微镜、X射线光电子能谱以及程序升温还原等表征手段分析了纳米纤维催化剂中离子掺杂导致活性变化的原因,并进行了碳烟氧化性能评价。结果表明:所有的纳米纤维催化剂均呈现单一的钙钛矿结构,当x≥0.3时,样品中出现新相K_(2)Mn_(4)O_(8)。样品中活性氧的数量是由K^(+)置换La^(3+)和Mn^(3+)→Mn^(4+)2个方面因素造成的。A位离子的置换增加了体系中氧缺陷程度,但是高含量K的引入引发新相的形成,使得体系中Mn^(3+)→Mn^(4+)开始占据主导地位,氧空位数量逐渐增加。样品La_(0.6)K_(0.4)MnO_(3)具有最佳的催化活性,其T_(50)为347℃。将纳米纤维与莫来石纤维按1:1比例制备的纸型催化剂活性最佳,T_(50)为478℃。
In order to construct a high-efficiency paper catalysts for soot removal,it is very important to design different active elements and realize the synergistic effects with the matrix fibers.A series of La_(1-x)K_(x)MnO_(3)(x=0,0.1,0.2,0.3,0.4,0.5)nanofiber catalysts were prepared via electrospinning.The oxidation performance of the catalyst for soot particles was examined by temperature programmed oxidation reaction.The defect effects induced by doping K^(+) ions in the LaMnO_(3) lattice on their catalytic performance evaluated by soot temperature-programmed oxidation were investigated by X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy and temperature programmed reduction analysis.The results show that all the nanofiber catalysts have a perovskite structure,while K_(2)Mn_(4)O_(8)as a new phase appears in the samples as x≥0.3.The amount of active oxygen in the sample is affected by K^(+) ions replacing La^(3+) ions and Mn^(3+) ions transferring into Mn^(4+) ions.The replacement of A-site ions increases the degree of oxygen defects in the system,while the transformation of Mn^(3+) ions into Mn^(4+) ions determining the number of oxygen vacancies as a new phase can occur at a great content of K^(+) ions doped in the system.The sample La_(0.6)K_(0.4)MnO_(3) has an optimum catalytic activity at T_(50) of 347℃.The paper-structured catalyst prepared with a nanofiber to matrix fiber ratio of 1:1 has a good catalytic activity at T50 of 478℃.
作者
刘煦婕
史宏斌
张学志
楚石磊
王磊
于刚
LIU Xujie;SHI Hongbin;ZHANG Xuezhi;CHU Shilei;WANG Lei;YU Gang(School of Materials Science and Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2022年第10期2622-2629,共8页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金基金(51602208)
石家庄铁道大学研究生创新基金(YC2021061)。
关键词
锰酸镧
纳米纤维
纸型催化剂
碳烟氧化
lanthanum manganate
nanofibers
paper catalysts
soot oxidation
