Molten Salt Assisted Self-Assembly (MASA) : synthesis of mesoporous silica-ZnO and mesoporous CdO thin films
Item Usage Stats
MetadataShow full item record
A series of mesostructured salt-silica-two surfactants (salt is [Zn(H2O)6](NO3)2, ZnX or [Cd(H2O)4](NO3)2, CdYand surfactants are cetyltrimethylammonium bromide (CTAB) and 10-lauryl ether, C12H25(OCH2CH2)10OH, C12EO10) thin films were synthesized by changing the Zn(II) or Cd(II)/SiO2 mole ratios. The films were prepared through spin coating of a clear solution of all the ingredients (salt, CTAB, C12E10, silica source (tetramethyl orthosilicate,TMOS, and water) and denoted as meso-silica-ZnX-n and meso-silica-CdY-n, where n is Zn(II) or Cd(II)/SiO2 mole ratios. The synthesis conditions were optimized by using the meso-silica-ZnX-1.14 and meso-silica-CdY-1.14 films and XRD, FT-IR spectroscopy, POM and SEM techniques. The stability of the films, especially in the high salt concentrations, was achieved above the melting point of salts. Slow calcination of the films, starting from the melting point of the salt to 450 oC has produced the mesoporous silica-metal oxide (ZnO and CdO) thin films, and denoted as meso-silica-ZnO-n and meso-silica-CdO-n, with n of 0.29, 0.57, 0.86, 1.14, and 1.43. The calcination process was monitored by measuring the FT-IR spectra and XRD patterns at different temperatures. Structural properties of the mesoporous films have been investigated using FT-IR spectroscopy, XRD, N2 sorption measurements, UV-Vis spectroscopy, SEM, TEM and EDS techniques. It has been found that the meso-silicaZnO-n and meso-silica-CdO-n films consist of nanocrystalline metal oxide nanoplates on the silica pore walls of the mesoporous framework. The formation of nanoplates of metal oxides was confirmed by etching the silica walls using diluted HF solution and by reacting with H2S and H2Se gases. The etching process produced CdO nanoplates without silica framework. The H2S and H2Se reactions with the CdO nanoplates or meso-silica-CdO have converted them to CdS and CdSe nanoplates or meso-silica-CdS and meso-silica-CdSe, respectively. Finally, a hypothetical surface coverage of metal oxide nanoplates has been calculated by combining the data of N2 sorption measurements, UV-Vis spectroscopy and TEM images and found that there is a full coverage of CdO and partial coverage of ZnO over silica walls in the meso-silica-CdO-n and meso-silica-ZnO-n thin films, respectively.
Lyotropic liquid crystals
TA418.9.T45 K37 2012
Showing items related by title, author, creator and subject.
Periodic mesoporous hydridosilica-synthesis of an "impossible" material and its thermal transformation into brightly photoluminescent periodic mesoporous nanocrystal silicon-silica composite Xie, Z.; Henderson, E. J.; Dag, Ö.; Wang, W.; Lofgreen, J. E.; Kübel, C.; Scherer, T.; Brodersen, P. M.; Gu, Zhong-Ze; Ozin, G. A. (2011)There has always been a fascination with "impossible" compounds, ones that do not break any rules of chemical bonding or valence but whose structures are unstable and do not exist. This instability can usually be rationalized ...
Fabrication of mesoporous metal chalcogenide nanoflake silica thin films and spongy mesoporous CdS and CdSe Türker, Y.; Karakaya, C.; Dag, Ö. (Wiley Online Library, 2012-02-16)Mesoporous silica metal oxide (ZnO and CdO) thin films have been used as metal ion precursors to produce the first examples of mesoporous silica metal sulfide (mesoSiO2@ZnS, meso-SiO2@CdS) or silica metal selenide ...
Organization of bridging organics in periodic mesoporous organosilicas (PMOs)-polarization micro-raman spectroscopy Dag, Ö.; Ozin, G. A. (Wiley, 2001)The organization of bridging organics in oriented periodic mesoporous organosilica film (OPMOF) was demonstrated using the polarization micro-Raman spectroscopy (PMRS) in conjunction with powder x-ray diffraction (PXRD) ...