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Issue Info: 
  • Year: 

    2012
  • Volume: 

    24
  • Issue: 

    6 (ISSUE NUMBER 116)
  • Pages: 

    446-453
Measures: 
  • Citations: 

    0
  • Views: 

    755
  • Downloads: 

    0
Abstract: 

Block copolymers and cetyltrimethylammonium bromide were used as templates in nano silica structure formation like MCM-41 (Mobil Composition of Matter), SBA16 (Santa Barbara Amorphous) and a new compound namely SPB (silicone mesoporous particles, prepared by sol-gel method using PPO-PEGPPO block copolymer) to compare the porosity and regularity of the products together. In this work tetraethylorthosilicate (TEOS), as silica source and alcohol as surface modifying agent were used because of having the main advantage, compared to an ionic template such as cetyltrimethylammonium bromide, in producing larger pores and thicker walls for holding larger catalytic molecules in their pores or increasing their resistance towards fragmentation. In order to study the copolymer as a template, SPB structure was prepared and compared with SBA16 which was found to have broader pore-size distribution and smaller specific surface area. Using alcohol in particle production resulted in higher formation rate of micelles with improved morphology. Nitrogen adsorption-desorption, X-ray diffraction and electron scanning microscopy confirmed the mesoporous structure and regularity of these synthesized materials. Finally a mechanism is proposed for the formation of these structures

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2013
  • Volume: 

    16
Measures: 
  • Views: 

    138
  • Downloads: 

    57
Abstract: 

INTRODUCTION: FUEL CELLS (FCS) ARE BEING CONSIDERED AS AN INTERESTING TECHNOLOGY IN ENERGY STORAGE. METHANOL CAN BE USED AS FUEL.DIRECT METHANOL FUEL CELL (DMFC) USUALLY SHOWS SLOW KINETIC AND HIGH OVER POTENTIAL AT SURFACE OF MOST OF USED ELECTRODES.TO SURMOUNT THESE PROBLEMS, DIFFERENT KIND OF MODIFIED ELECTRODES HAVE BEEN INTRODUCED. SBA AS A NOVEL FAMILY OF MESOPOROUS SILICAS HAS SOME FEATURES SUCH AS LARGE PORES, THICK PORE WALLS AND HIGH HYDROTHERMAL STABILITY.SBA-16 IS A MEMBER OF THE SBA FAMILY WITH 3D CUBIC SYSTEM.AMONG THE REPORTED CUBIC MESOPOROUS SILICA MATERIALS, SBA-16 APPEARS TO BE ONE OF THE BEST CANDIDATES FOR CATALYTIC SUPPORT BECAUSE OF GOOD THERMAL STABILITY OF THE THICK WALL, ECONOMICAL SYNTHESIS WITH INEXPENSIVE SILICA SOURCES, AND THREE DIMENSIONAL LARGE PORES [1].

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