摘要
以阴阳复合表面活性剂调控的溶胶凝胶法合成了氧化锰八面体分子筛(OMS-2)。采用TG-DSC、XRD、低温氮气吸附-脱附、TEM、FTIR、UV-Vis、O2-TPD以及H2-TPR等技术对制备的材料的结构和氧化还原性能进行了表征,考察了该锰氧化物材料对二甲醚催化燃烧反应的催化性能。结果表明,合成的OMS-2材料属于cryptomelane结构,单独的阴离子或者阳离子表面活性剂作模板剂时,制备的材料其外形均不规整,而采用二者按照一定物质的量的比混合时,可以得到均一的纳米棒状结构。O2-TPD和H2-TPR结果说明,制备的OMS-2材料具有丰富的氧物种,低温下易还原,因而在二甲醚催化燃烧中表现出了良好的催化性能。其中采用阴阳复合模板剂制备的样品,具有最低的氧脱附温度和氢气还原温度,因而在二甲醚催化燃烧中表现出最优的催化性能,二甲醚燃烧的完全燃烧温度T90为170℃,反应产物仅有CO2和H2O。
Manganese oxide octahedral molecular sieves（OMS-2） were synthesized by sol-gel method with KMnO4 and maleic acid as raw materials and a surfanetant such as sodium dodecyl sulfate（SDS）, cetyl trimethyl ammonium bromide（CTAB） as the template. The structure of the catalysts was characterized by XRD, N2 adsorption-desorption, TEM,FTIR,UV-Vis,O2-TPD and H2-TPR techniques. The catalytic activity of the OMS-2 in dimethyl ether（DME） combustion was also evaluated. The results show that the catalyst prepared under the co-existence of CTAB and SDS has the typical cryptomelane structure with one dimensional channel and a relatively uniform short rodlike shape with a length of 75 nm. The mixed cationic/anionic surfanetant works as a structure-directing agent, which leads to the transformation of the OMS-2 structure from the conventional nano-particle to nanorod. O2-TPD and H2-TPR characterization show that the OMS-2 samples have abundant facile lattice oxygen and can be easily reduced, which leads to excellent performance in the DME catalytic combustion. The catalyst synthesized with mixed surfanctants showed the best catalytic activity for DME catalytic combustion with a complete combustion temperature（T90） of 170℃, with only CO2and H2O as the reaction products.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2008年第11期1852-1858,共7页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金(No.20203012)
广东省高等学校自然科学研究重点项目(No.06Z011)
广东省科技计划项目(No.2005B10201053)
广东省自然科学基金团队项目(No.4205301)
广州市科技计划项目(No.2006J1-C0501)
广东工业大学新进科研基金(No.XJ200604)资助项目
关键词
氧化锰
模板剂
阴阳复合表面活性剂
二甲醚
催化燃烧
manganese oxide
template
cationic/anionic surfanctants
dimethyl ether
catalytic combustion
