摘要
在采用有机相法制备钒磷氧(VPO)催化剂前驱体的过程中,添加铋盐、二甲基亚砜(DMSO)和聚乙二醇,制得了一系列催化剂,并将其用于正丁烷选择氧化反应.结果表明,当V:Bi:DMSO摩尔比=1:0.0035:0.1时,VPO催化剂上的顺酐摩尔收率最高,达55.1%.低温氮气吸附、X射线衍射、扫描电子显微镜、X射线能谱和傅里叶变换红外光谱表征结果表明,该催化剂的比表面积达到38.2 m2/g,有沿(200)晶面的择优取向,Bi原子取代V原子,形成固溶体,引起P在表面富集,生成了大量具有纳米尺度的催化剂颗粒.三种助剂在催化剂前驱体形成过程中协同作用,降低了前驱体晶体成核过程的表面能,加速了VOHPO4.0.5H2O的形核速率,阻抑了前驱体颗粒的聚集长大,形成了稳定的纳米颗粒.
A nanostructured vanadium phosphorous oxide（VPO） precursor,VOHPO4.0.5H2O,was directly synthesized by reduction of V2O5 using an improved organic solvent method.Bismuth salt,dimethyl sulfoxide,and polyethylene glycol were used in the preparation process.With the molar ratio of V：Bi：DMSO being 1：0.0035：0.1,the VPO catalyst showed the maleic anhydride molar yield of 55.1% in the n-butane oxidation.The characterization of the catalyst by N2 adsorption,X-ray diffraction,scanning electron microscopy,energy dispersive X-ray spectroscopy,and Fourier transform infrared spectroscopy showed that the VPO catalyst had the specific surface area of 38.2 m2/g and preferred（200） orientation,and its V was substituted for Bi,causing surface P enrichment and enhanced lattice distortion.The catalyst also accelerated the adsorption and dissociation of O2.A synergistic effect was observed among the three promoters in the process of precursor formation,which decreased the surface energy of the nucleation progress of the VOHPO4.0.5H2O precursor and significantly inhibited its aggregation.Therefore,stabilized nano-sized VPO particles can be generated.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第4期284-290,共7页
关键词
铋盐
二甲基亚砜
助剂
钒磷氧催化剂
纳米结构
正丁烷
顺酐
bismuth salt
dimethyl sulfoxide
promoter
vanadium phosphorous oxide catalyst
nanostructure
n-butane
maleic anhydride
