摘要
用共沉淀法制备了一组不同组成的MnxCo3-xO4尖晶石型复合氧化物,表面负载碱金属助剂制备改性催化剂,用于催化分解N2O.用X射线衍射(XRD)、N2物理吸附(BET)、红外光谱(FTIR)、扫描电镜(SEM)、H2程序升温还原(H2-TPR)、X射线光电子能谱(XPS)等技术表征催化剂结构.考察了复合氧化物组成、碱金属助剂类型、钾前驱物等制备参数对催化剂结构和催化活性的影响.结果表明:添加助剂K、Cs降低了催化剂表面Co、Mn元素的电子结合能,弱化了Co—O和Mn—O键,有利于氧物种的脱除,提高了催化剂活性.优化出了活性较高的催化剂K/Mn0.4Co2.6O4(K2CO3),有氧无水、有氧有水气氛400℃连续反应50 h,N2O转化率分别保持100%和74.2%,催化剂稳定性较高.
A series of MnxCo3- xO4 spinel oxides with different compositions were prepared by co-precipitation met hod,and incipiently impregnated by alkali metal salt solutions to make modified catalysts for N2 O decomposition.The techniques such as X-ray diffraction( XRD),nitrogen physisorption( BET),Fourier transformed infrared( FTIR),scanning electron microscopy( SEM),hydrogen temperature-programmed reduction( H2-TPR) and X-ray photoelectron spectroscopy( XPS) were used to characterize these catalysts. The effects of mixed oxide compositions,additive types,and potassium precursors on catalysts structure and catalytic activity were investigated. It is shown that the addition of potassium and cesium onto Mn-Co mixed oxide resulted in the decrease in binding energies of Mn and Co elements and the weakening of Co—O and Mn—O bonds,thus the modified catalysts activity was enhanced. The most active catalyst for N2 O decomposition was K / Mn0. 4Co2. 6O4(K2CO3) catalyst,over which100% and 74. 2% conversion of N2 O can be maintained at 400 ℃ after continuous reaction for 50 h in oxygen-alone and oxygen-steam together,respectively.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2015年第3期246-255,共10页
Journal of Molecular Catalysis(China)
基金
山东省科技发展计划项目(2012GSF11708)
烟台大学研究生科技创新基金项目(GIFYTU)
