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Title: Surface Functionalization of Ordered Mesoporous CarbonsA Comparative Study

Authors:
 [1];  [2];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Philip Morris, Richmond, VA (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1059297
DOE Contract Number:
AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Langmuir; Journal Volume: 21; Journal Issue: 25
Country of Publication:
United States
Language:
English

Citation Formats

Li, Zuojiang, Yan, Wenfu, and Dai, Sheng. Surface Functionalization of Ordered Mesoporous CarbonsA Comparative Study. United States: N. p., 2005. Web. doi:10.1021/la051608u.
Li, Zuojiang, Yan, Wenfu, & Dai, Sheng. Surface Functionalization of Ordered Mesoporous CarbonsA Comparative Study. United States. doi:10.1021/la051608u.
Li, Zuojiang, Yan, Wenfu, and Dai, Sheng. Thu . "Surface Functionalization of Ordered Mesoporous CarbonsA Comparative Study". United States. doi:10.1021/la051608u.
@article{osti_1059297,
title = {Surface Functionalization of Ordered Mesoporous CarbonsA Comparative Study},
author = {Li, Zuojiang and Yan, Wenfu and Dai, Sheng},
abstractNote = {},
doi = {10.1021/la051608u},
journal = {Langmuir},
number = 25,
volume = 21,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2005},
month = {Thu Dec 01 00:00:00 EST 2005}
}
  • The introduction of mesoporous silicas in the 1990s has offered new opportunities for the engineering of ordered catalytic nanoreactors, but the acid properties of mesoporous silicas are rather poor. Herein, mesoporous silica (SBA-15) surfaces were functionalized by zirconium phosphate via two methods recently developed in our group. Zr(OPr){sub 4} and POCl{sub 3} were used as appropriate precursors in both methods. The main difference between these methods lies in whether Zr(OPr){sub 4} is grafted onto SBA-15 first and POCl{sub 3} second (method 1) or the grafting process takes place in one pot, with SBA-15, Zr(OPr){sub 4}, and POCl{sub 3} altogether (methodmore » 2). More zirconium phosphate could be grafted by repeating the above procedures. The materials were characterized by ICP-OES, XRD, N{sub 2} adsorption-desorption, TEM, {sup 31}P and {sup 29}Si MAS NMR, and NH{sub 3}-TPD, and their applications in catalytic isopropanol dehydration, cumene cracking, and metal-ion adsorption were demonstrated. Aluminum phosphate-modified SBA-15 samples could be obtained via these two methods as well. This work enriches the family of metal phosphate-functionalized mesoporous silicas as new solid acid catalysts.« less
  • Ordered mesoporous carbon materials were prepared by pyrolysis of sucrose and furfuryl alcohol templated in the ordered mesoporous silicate SBA-15. The structure of SBA-15 template was modified by changing the calcination temperature, we investigate the structural transformation of the silica template with calcination temperature using X-ray diffraction and nitrogen adsorption isotherms. SBA-15 calcined to 300 C has a total pore volume of 1.13 cm{sup 3}/g, a BET surface area of 1100 m2/g, and a pore spacing of 114 Angstroms; when calcined to 90 C the corresponding values are 0.40 cm{sup 3}/g, 330 m{sup 2}/g and 92.5 Angstroms. Despite marked differencesmore » in SBA-15 template structure, the pore size distribution of the ordered mesoporous carbons is more dependent on the choice of precursor than on SBA-15 pore geometry. The BET surface areas of ordered mesoporous carbons made from aqueous sucrose solutions (850-1050 m2/g) are independent of template geometry; while surface area of materials made from furfuryl alcohol (530-1190 m2/g) are a reflection of template geometry. Near-edge X-ray fine-structure (NEXAFS) spectroscopy reveal that the template-carbon interaction during the pyrolysis of sucrose-based carbons exerts a strong influence on the surface structure of final product, and that such effects are largely absent in the furfuryl alcohol-based materials. The pair-distribution function (PDF) calculated from high-energy synchrotron scattering measurements corroborates the NEXAFS results, yet also show that the template effect on the bulk carbon is minimal. Template compression acting in conjunction with hydrothermally induced effects exerted on the carbon during pyrolysis drives the resulting carbon to a more graphitic state.« less
  • No abstract prepared.