摘要
以纺锤体状单晶氧化铜、片状单晶氧化镧和硝酸盐为金属源,通过水热法并灼烧所得产物,制备了具有纺锤体状、棒状和短链状类钙钛矿型氧化物La2-xSrxCuO4(x=0,1)单晶纳微米粒子.采用X射线衍射、扫描电镜、透射电镜、X射线光电子能谱、氢气程序升温还原、氧气程序升温脱附以及N2吸附等技术对所得催化剂的物化性质进行了表征,考察了这些样品催化甲烷氧化反应的性能.结果表明,将Sr部分引入La2CuO4的晶格中可增加催化剂表面吸附氧量、Cu3+含量和还原能力.在空速为50 000 ml/(g-h)和CH4/O2摩尔比为1/10的条件下,以硝酸盐为金属源制得的LaSrCuO4表现出最高的催化活性,在675 oC时甲烷反应速率高达40.9 mmol/(g-h).这一优良的催化性能与其表面较高的氧空位浓度、独特的单晶结构和特定的表面形貌有关.
The single-crystalline perovskite-like oxide La2-xSrxCuO4（x = 0,1） nano/mircoparticles with spindle-,rod-,and short chain-like morphologies were synthesized with spindle-like single-crystalline CuO,plate-like single-crystalline La2O3,and nitrates as metal source by hydrothermal treatment and calcination.Physiochemical properties of these materials were characterized by X-ray diffraction,scanning elec-tron microscopy,transmission electron microscopy,selected area electron diffraction,X-ray photoelectron spectroscopy,hydrogen tempera-ture-programmed reduction,oxygen temperature-programmed desorption,and specific surface area measurements.The catalytic perform-ance of the single-crystalline perovskite-like oxides with specific morphologies for methane combustion was also examined.It is shown that the partial doping of Sr to the La2CuO4 lattice increased the surface adsorbed oxygen amount,Cu3＋ content,and reducibility.Under the con-ditions of space velocity of 50 000 ml/（g？h） and CH4/O2 molar ratio of 1/10,the LaSrCuO4 prepared hydrothermally with nitrates of lantha-num,strontium,and copper as metal source exhibited the highest catalytic activity,giving a methane consumption rate of up to 40.9 mmol/（g-h） at 675 oC.Such an excellent catalytic performance may be associated with its higher surface oxygen vacancy concentration,unique single-crystalline structure,and specific surface morphology.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2009年第4期347-354,共8页
基金
北京市教委科技发展计划重点项目暨北京市自然科学基金(B类)重点项目(KZ200610005004)
关键词
类钙钛矿氧化物
锶取代铜酸镧
水热合成法
特定表面形貌
甲烷氧化
single-crystalline perovskite-like oxide
strontium-substituted lanthanum cuprate
hydrothermal synthesis
specific morphology
methane oxidation
