tailieunhanh - Báo cáo hóa học: " Ionic liquid-templated preparation of mesoporous silica embedded with nanocrystalline sulfated zirconia"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Ionic liquid-templated preparation of mesoporous silica embedded with nanocrystalline sulfated zirconia | Ward et al. Nanoscale Research Letters 2011 6 192 http content 6 1 192 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Ionic liquid-templated preparation of mesoporous silica embedded with nanocrystalline sulfated zirconia Antony J Ward Ajit A Pujari Lorenzo Costanzo Anthony F Masters Thomas Maschmeyer Abstract A series of mesoporous silicas impregnated with nanocrystalline sulphated zirconia was prepared by a sol-gel process using an ionic liquid-templated route. The physicochemical properties of the mesoporous sulphated zirconia materials were studied using characterisation techniques such as inductively coupled optical emission spectroscopy X-ray diffraction transmission electron microscopy energy-dispersive X-ray microanalysis elemental analysis and X-ray photoelectron spectroscopy. Analysis of the new silicas indicates isomorphous substitution of silicon with zirconium and reveals the presence of extremely small 10 nm polydispersed zirconia nanoparticles in the materials with zirconium loadings from to wt. . Introduction Solid acids and superacids have attracted great interest due to their potential applications in many areas of the chemical industry ranging from petrochemicals to fine chemical production 1-5 . One such example of a strong solid acid is sulphated zirconia probably first reported in the patent literature 6 then further exemplified 7 almost two decades later. This material has shown remarkable catalytic activity for a range of reactions which are not catalysed by conventional solid catalysts 1 8 9 . Examples of such reactions include the skeletal isomerisation of alkanes 10 the alkylation of alkanes by alkenes 11 and the low-temperature cracking of polyolefins 12 and in the presence of metal dopants the activation Pt of methane 13 and either alone or promoted by Fe or Mn ethane 14 to name a few. Numerous methods exist for the preparation of sulphated zirconia materials. .