制备了一系列NH4NaY分子筛,采用小角度27 Al MAS NMR考察了焙烧温度、焙烧时间、Na+含量以及空气湿度对焙烧脱铝程度的影响。结果表明:在空气中焙烧NH4NaY分子筛时,焙烧温度会影响脱铝后形成的非骨架铝的总量及非骨架铝物种的组成,焙烧...制备了一系列NH4NaY分子筛,采用小角度27 Al MAS NMR考察了焙烧温度、焙烧时间、Na+含量以及空气湿度对焙烧脱铝程度的影响。结果表明:在空气中焙烧NH4NaY分子筛时,焙烧温度会影响脱铝后形成的非骨架铝的总量及非骨架铝物种的组成,焙烧温度较高时,Na+含量对形成的非骨架铝的量和非骨架铝物种的组成都有影响,焙烧温度较低时,Na+含量仅会影响非骨架铝的量;焙烧时间对脱铝程度的影响与焙烧温度及Na+含量有关,焙烧温度低时,焙烧时间对脱铝程度没有影响,焙烧温度高时,则焙烧时间对脱铝程度的影响随Na+含量的升高而降低;空气湿度对脱铝程度也有一定的影响,空气湿度越大,从骨架上脱出的铝越多。展开更多
A series of Y zeolites exchanged with different amount of cerium and lanthanum cations were investigated. Comprehensive routine analysis tools including X-ray photoelectron spectroscopy（XPS）, X-ray fluorescence（XRF...A series of Y zeolites exchanged with different amount of cerium and lanthanum cations were investigated. Comprehensive routine analysis tools including X-ray photoelectron spectroscopy（XPS）, X-ray fluorescence（XRF）, X-ray diffraction（XRD） and Py-Fourier transform infrared spectroscopy（Py-FTIR） were used to identify the cation location, and the result was verified via XRD Rietveld study. The results revealed that almost all the RE cations in RE-4, most cations in RE-8 to RE-14 and part of cations in RE-16 were located in the sodalite cage. The Al^（IV）/（Al^V＋Al^（VI）） values revealed by ^（27）Al MAS NMR spectra, the silicon aluminum ratio of the framework（SARF） values deduced from ^（29）Si MAS NMR spectra and XRD, and hydroxyl amount were reasonably in accordance with the location and content of rare earth cations. The hydrothermal stability derived from in situ XRD investigation and catalyst activity provided by micro-activity test manifested that samples RE-8 to RE-14 exhibited better performances than RE-4 and RE-16, among which RE-12 had the best properties. The phenomena were interpreted by the cation location and structural properties.展开更多
文摘制备了一系列NH4NaY分子筛,采用小角度27 Al MAS NMR考察了焙烧温度、焙烧时间、Na+含量以及空气湿度对焙烧脱铝程度的影响。结果表明:在空气中焙烧NH4NaY分子筛时,焙烧温度会影响脱铝后形成的非骨架铝的总量及非骨架铝物种的组成,焙烧温度较高时,Na+含量对形成的非骨架铝的量和非骨架铝物种的组成都有影响,焙烧温度较低时,Na+含量仅会影响非骨架铝的量;焙烧时间对脱铝程度的影响与焙烧温度及Na+含量有关,焙烧温度低时,焙烧时间对脱铝程度没有影响,焙烧温度高时,则焙烧时间对脱铝程度的影响随Na+含量的升高而降低;空气湿度对脱铝程度也有一定的影响,空气湿度越大,从骨架上脱出的铝越多。
基金Project supported by the Foundation of SINOPEC(111015)
文摘A series of Y zeolites exchanged with different amount of cerium and lanthanum cations were investigated. Comprehensive routine analysis tools including X-ray photoelectron spectroscopy（XPS）, X-ray fluorescence（XRF）, X-ray diffraction（XRD） and Py-Fourier transform infrared spectroscopy（Py-FTIR） were used to identify the cation location, and the result was verified via XRD Rietveld study. The results revealed that almost all the RE cations in RE-4, most cations in RE-8 to RE-14 and part of cations in RE-16 were located in the sodalite cage. The Al^（IV）/（Al^V＋Al^（VI）） values revealed by ^（27）Al MAS NMR spectra, the silicon aluminum ratio of the framework（SARF） values deduced from ^（29）Si MAS NMR spectra and XRD, and hydroxyl amount were reasonably in accordance with the location and content of rare earth cations. The hydrothermal stability derived from in situ XRD investigation and catalyst activity provided by micro-activity test manifested that samples RE-8 to RE-14 exhibited better performances than RE-4 and RE-16, among which RE-12 had the best properties. The phenomena were interpreted by the cation location and structural properties.
