Eun-Bum Cho - Academia.edu (original) (raw)

Papers by Eun-Bum Cho

Research paper thumbnail of Highly Stable Mesoporous Ni-Phyllosilicate Particle Under High Temperature Hydrothermal and Base Conditions Towards Industrial Catalytic Applications

Research paper thumbnail of 3D interconnected polymer/mesoporous silica nanoparticle hybrid materials with hierarchical macro/meso-structures for heavy metal adsorption

New journal of chemistry, 2024

Research paper thumbnail of 이동현상 / 고분자유변학 : 블록 공중합체의 미셀 형성에 관한 연구

Research paper thumbnail of ChemInform Abstract: Ceria-Containing Ordered Mesoporous Silica: Synthesis, Properties, and Applications

Research paper thumbnail of Multifunctional periodic mesoporous organosilicas prepared with block copolymer: Composition effect on morphology

Microporous and Mesoporous Materials, Aug 1, 2008

... the BJH method. The Brunauer–Emmet–Teller (BET) specific area and the total pore volume were ... more ... the BJH method. The Brunauer–Emmet–Teller (BET) specific area and the total pore volume were calculated at the relative pressure range from 0.06 to 0.2 and at a fixed relative pressure of 0.99, respectively. The solid-state ...

Research paper thumbnail of Multifunctional periodic mesoporous organosilicas with bridging groups formed via dynamic covalent chemistry

Chemical Communications, 2010

Experimental 1. Materials. (3-aminopropyl)triethoxysilane (99% APTES, Aldrich) and 4-(trimethoxys... more Experimental 1. Materials. (3-aminopropyl)triethoxysilane (99% APTES, Aldrich) and 4-(trimethoxysilyl)aniline (90% TMA, Gelest) were used as amine sources and triethoxysilyl butyraldehyde (90% TEBA, Gelest) was used as an aldehyde-containing organosilica source. 1,2-bis(triethoxysilyl)ethane (96% BTEE, Aldrich), 1,4-bis(triethoxysilyl)benzene (96% BTEB, Aldrich) and 2,5-bis(triethoxysilyl)thiophene (96% BTET, JSI silicone) were used as bridged organosilanes. Organosilica precursors were used as purchased without further purification. Silver nitrate (AgNO 3 , Fisher Scientific), hydrogen peroxide (35 wt% H 2 O 2 , Acros) and acetonitrile (CH 3 CN, Fisher Scientific) were used for oxidation of aldehydes to carboxylic acids inside the PMO materials. Poly(ethylene oxide)-poly(DL-lactic acid-co-glycolic acid)-poly(ethylene oxide), EO 16 (L 29 G 7)EO 16 , triblock copolymer (LGE538, M n (GPC) = 5310, M n (NMR) = 4220, polydispersity index (PI) = 1.28, and fraction Φ PEO = 0.38) was synthesized through a ring opening polymerization. LGE538 triblock copolymer was used as a soft template for hexagonal mesostructure. 2. Preparation of Multifunctional Periodic Mesoporous Organosilicas. The multifunctional LBMA-PMOs were synthesized by self-assembly of LGE538, BTEB, APTES and TEBA under 0.1 M HCl acidic conditions. The 1:1 molar ratio of APTES and TEBA was used in the synthesis of LBMA-PMOs by varying the composition of reactive organosilanes in relation to BTEB as follows: ([APTES] + [TEBA]):[

Research paper thumbnail of Ultrabright Fluorescent Mesoporous Silica Nanoparticles

Small, Sep 21, 2010

The fi rst successful approach to synthesizing ultrabright fl uorescent mesoporous silica nanopar... more The fi rst successful approach to synthesizing ultrabright fl uorescent mesoporous silica nanoparticles is reported. Fluorescent dye is physically entrapped inside nanochannels of a silica matrix created during templated sol-gel self-assembly. The problem of dye leakage from open channels is solved by incorporation of hydrophobic groups in the silica matrix. This makes the approach compatible with virtually any dye that can withstand the synthesis. The method is demonstrated using the dye Rhodamine 6G. The obtained 40-nm silica particles are about 30 times brighter than 30-nm coated water-soluble quantum dots. The particles are substantially more photostable than the encapsulated organic dye itself.

Research paper thumbnail of Newly design and synthesis of Ni–Ir–Ru-doped mesoporous silica open-frameworks for admirable electrochemical water-oxidation application

International Journal of Hydrogen Energy

Research paper thumbnail of Bifunctional Periodic Mesoporous Organosilicas with Thiophene and Isocyanurate Bridging Groups

Research paper thumbnail of Synthesis of highly ordered mesoporous benzene-silicas using PEO–PLGA–PEO triblock copolymers

Research paper thumbnail of Biosynthesis of Nanoparticles from Various Biological Sources and Its Biomedical Applications

Molecules, Jun 2, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Direct Solvent-Free Selective Hydrogenation of Levulinic Acid to Valeric Acid Over Multi-Metal (Nixcoymnzalw)-Doped Mesoporous Silica Catalysts

Research paper thumbnail of Carbon‐embedded mesoporous transition multimetal oxide nanospheres for long‐lasting hybrid cells

International Journal of Energy Research, May 20, 2022

Research paper thumbnail of 폴리(비닐리덴 플루오라이드)(PVDF) 막 위에 코팅되는 플루오로에틸렌 비닐 에테르(FEVE) 막의 가교형태에 따른 내자외선성 및 물성 변화 연구

Polymer(Korea), Mar 1, 2017

This study describes the effect of crosslinking types on chemical and physical properties and UV ... more This study describes the effect of crosslinking types on chemical and physical properties and UV resistance of fluoroethylene vinyl ether (FEVE) layer over poly(vinylidene fluoride) (PVDF) in coil-coating. Hexamethoxymethylmelamine (HMMM) of melamine type and hexamethylene diisocyanate (HDI) of isocyanate type were used respectively as crosslinkers of high gloss and transparent FEVE layer on the PVDF coating layer. The evaluation of physical property and UV (UV-B) resistance was processed within ASTM standards. Urethane-reaction group using HDI showed relatively much better stability against UV (UV-B) than melamine reaction group of HMMM, while some physical and chemical resistances were found to be weaker. Also, in spite of the same melamine reaction group, the UV resistance was varied according to the ratio of HMMM cross-linker. From this study, it is expected to enhance weatherability as well as minimize the film deterioration from UV through optimizing crosslinking reaction in FEVE/PVDF double layer coating as a building exterior application.

Research paper thumbnail of Sol-gel synthesis and characterization of mesoporous organosilicas by using block copolymer templates

MRS Proceedings, 2000

Mesoporous organosilicas based on a bridged organosilicate have been synthesized using a triblock... more Mesoporous organosilicas based on a bridged organosilicate have been synthesized using a triblock PEO-PLGA-PEO copolymer containing more hydrophobic poly(DL-lactic acid-coglycolic acid) block and the structural difference between mesoporous organosilicas prepared from PEO-PLGA-PEO and PEO-PPO-PEO block templates is discussed.

Research paper thumbnail of Newly Designed Mesoporous Silica and Organosilica Nanostructures Based on Pentablock Copolymer Templates in Weakly Acidic Media

Nanomaterials, Sep 27, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Role of block copolymer template for tailoring crystal structure and band gap of titania in mesoporous silica and organosilica particles

Ceramics International, Feb 1, 2020

This work presents the tailoring of distinct titania (titania oxide) (TiO 2) crystal structures i... more This work presents the tailoring of distinct titania (titania oxide) (TiO 2) crystal structures inside the mesoporous silica and organosilica using several different block copolymer templates in acidic aqueous solution with different acidity. Different crystal structures of TiO 2 have been obtained as rutile and anatase phases, mainly depending on the chemical composition of block copolymer templates used in this study. A PEO-PLGA-PEO (EO 17 (L 28 G 7)EO 17 , LGE54) triblock copolymer, as well as typical Pluronic P123 (EO 20 PO 70 EO 20) and F127 (EO 106 PO 70 EO 106) triblock copolymers was employed as structure-directing templates for the sol-gel reaction of silane precursors. As silica and organosilica precursors, tetraethyl orthosilicate (TEOS), 1,2-bis(triethoxysilyl) ethane (BTEE), and 1,4-bis(triethoxysilyl)benzene (BTEB) were utilized with a titanium butoxide precursor. The crystal structure of TiO 2 and its corresponding band gap were investigated using X-ray diffraction (XRD) and ultraviolet-visible spectroscopy (UV-vis) measurements, respectively. Anatase crystalline phase of TiO 2 was found in the mesoporous sample prepared with Pluronic copolymer (i.e. P123 and F127) templates. On the other hand, the rutile phase was developed only in mesoporous samples prepared with an LGE54 PEO-PLGA-PEO triblock copolymer template. It was found the TiO 2 crystal structure is varied mainly depending on the polymer template under various strong acidic conditions. It seems that a thermodynamically more stable rutile phase can be formed using a more hydrophobic LGE54 template which supplies stronger micelle core as a platform. Further, it is known that the incorporation of TiO 2 in mesoporous silica and organosilica samples induces the conduction activity, especially toward the blue light region. Thus, this work can be applied to produce effective blue region semiconductor material with different crystallite structures by tuning the precursors and copolymer templates.

Research paper thumbnail of Synthesis of ordered Ca- and Li-doped mesoporous silicas for H<sub>2</sub> and CO<sub>2</sub> adsorption at ambient temperature and pressure

RSC Advances, 2018

Ca-and Li-doped mesoporous silicas have been prepared successfully using cetyltrimethylammonium b... more Ca-and Li-doped mesoporous silicas have been prepared successfully using cetyltrimethylammonium bromide (CTAB) surfactant in basic media. Sol-gel synthesis and hydrothermal treatment produced highly ordered mesoporous Ca and Li loaded silica particles. The MCM-41 type mesostructures, the porosity, the pore sizes as well as the surface area of Ca-and Li-silicas have been thoroughly investigated using small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and N 2 sorption analysis. Samples prepared with varying amounts of Li and Ca loading have been further analyzed using inductive coupled plasma-atomic emission spectroscopy (ICP-AES) and field-emission scanning electron microscopy (FESEM) with an energy dispersive spectral attachment (EDS), which confirmed quite a large amount of Ca while the amount of Li was not enough. Additionally, H 2 and CO 2 gas uptake studies of these metal-loaded silicas have been carried out using a thermogravimetric analyzer (TGA) at normal temperature (25 C) and pressure (1 atm). H 2 uptake of up to 10 mmol g À1 by Ca-doped silica was recorded. CO 2 and H 2 selectivity were tested with both pure metal-MCM-41 and amine loaded silica using pure N 2 gas and a mixed flow of CO 2 /N 2 and H 2 /N 2. The effect of temperature on CO 2 uptake was also studied using Ca-MCM-41 materials.

Research paper thumbnail of Surfactant-assisted synthesis of ceria–titania-rich mesoporous silica materials and their catalytic activity towards photodegradation of organic dyes

Dalton Transactions, 2017

Figure S1: The plot of C/C 0 versus time (t) for degradation of Rhodamine B dye using only H 2 O ... more Figure S1: The plot of C/C 0 versus time (t) for degradation of Rhodamine B dye using only H 2 O 2. Inset represents a plot of ln(C/C 0) versus time (t) to calculate the rate constant.

Research paper thumbnail of Effect of Morphology and Pore Size of Sulfonated Mesoporous Benzene-silicas in the Preparation of Poly(vinyl alcohol)-Based Hybrid Nanocomposite Membranes for Direct Methanol Fuel Cell Application

Journal of Physical Chemistry B, Jul 1, 2009

Sulfonated mesoporous benzene-silicas were introduced into a poly(vinyl alcohol) (PVA) polymer ma... more Sulfonated mesoporous benzene-silicas were introduced into a poly(vinyl alcohol) (PVA) polymer matrix to act as a barrier for methanol crossover, to prepare composite electrolyte membranes for direct methanol fuel cell applications. Highly ordered 2D hexagonal mesoporous benzene-silicas were prepared using 1,4-bis(triethoxysilyl)benzene (BTEB) organosilica precursor and two kinds of organic templates, such as an octadecyltrimethylammonium bromide (ODTMA) and a Pluronic P123 poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer, to investigate the effect of the morphology and the pore size on the methanol permeability and the proton conductivity of the membranes. The sulfonated mesoporous benzene-silica and PVA were mixed with a sulfosuccinic acid (SSA) cross-linker to improve the membrane stability from mechanical and conductive viewpoints. The physical and chemical characterization of the hybrid electrolyte membranes was performed by varying the contents of sulfonated mesoporous benzene-silicas and SSA. All the hybrid membranes studied showed good performance in lowering the methanol crossover (i.e., approximately 68% reduction in comparison with the Nafion117 membrane), and mesoporous benzene-silica with smaller particle morphology and pores (2-3 nm) was observed to be a more effective additive.

Research paper thumbnail of Highly Stable Mesoporous Ni-Phyllosilicate Particle Under High Temperature Hydrothermal and Base Conditions Towards Industrial Catalytic Applications

Research paper thumbnail of 3D interconnected polymer/mesoporous silica nanoparticle hybrid materials with hierarchical macro/meso-structures for heavy metal adsorption

New journal of chemistry, 2024

Research paper thumbnail of 이동현상 / 고분자유변학 : 블록 공중합체의 미셀 형성에 관한 연구

Research paper thumbnail of ChemInform Abstract: Ceria-Containing Ordered Mesoporous Silica: Synthesis, Properties, and Applications

Research paper thumbnail of Multifunctional periodic mesoporous organosilicas prepared with block copolymer: Composition effect on morphology

Microporous and Mesoporous Materials, Aug 1, 2008

... the BJH method. The Brunauer–Emmet–Teller (BET) specific area and the total pore volume were ... more ... the BJH method. The Brunauer–Emmet–Teller (BET) specific area and the total pore volume were calculated at the relative pressure range from 0.06 to 0.2 and at a fixed relative pressure of 0.99, respectively. The solid-state ...

Research paper thumbnail of Multifunctional periodic mesoporous organosilicas with bridging groups formed via dynamic covalent chemistry

Chemical Communications, 2010

Experimental 1. Materials. (3-aminopropyl)triethoxysilane (99% APTES, Aldrich) and 4-(trimethoxys... more Experimental 1. Materials. (3-aminopropyl)triethoxysilane (99% APTES, Aldrich) and 4-(trimethoxysilyl)aniline (90% TMA, Gelest) were used as amine sources and triethoxysilyl butyraldehyde (90% TEBA, Gelest) was used as an aldehyde-containing organosilica source. 1,2-bis(triethoxysilyl)ethane (96% BTEE, Aldrich), 1,4-bis(triethoxysilyl)benzene (96% BTEB, Aldrich) and 2,5-bis(triethoxysilyl)thiophene (96% BTET, JSI silicone) were used as bridged organosilanes. Organosilica precursors were used as purchased without further purification. Silver nitrate (AgNO 3 , Fisher Scientific), hydrogen peroxide (35 wt% H 2 O 2 , Acros) and acetonitrile (CH 3 CN, Fisher Scientific) were used for oxidation of aldehydes to carboxylic acids inside the PMO materials. Poly(ethylene oxide)-poly(DL-lactic acid-co-glycolic acid)-poly(ethylene oxide), EO 16 (L 29 G 7)EO 16 , triblock copolymer (LGE538, M n (GPC) = 5310, M n (NMR) = 4220, polydispersity index (PI) = 1.28, and fraction Φ PEO = 0.38) was synthesized through a ring opening polymerization. LGE538 triblock copolymer was used as a soft template for hexagonal mesostructure. 2. Preparation of Multifunctional Periodic Mesoporous Organosilicas. The multifunctional LBMA-PMOs were synthesized by self-assembly of LGE538, BTEB, APTES and TEBA under 0.1 M HCl acidic conditions. The 1:1 molar ratio of APTES and TEBA was used in the synthesis of LBMA-PMOs by varying the composition of reactive organosilanes in relation to BTEB as follows: ([APTES] + [TEBA]):[

Research paper thumbnail of Ultrabright Fluorescent Mesoporous Silica Nanoparticles

Small, Sep 21, 2010

The fi rst successful approach to synthesizing ultrabright fl uorescent mesoporous silica nanopar... more The fi rst successful approach to synthesizing ultrabright fl uorescent mesoporous silica nanoparticles is reported. Fluorescent dye is physically entrapped inside nanochannels of a silica matrix created during templated sol-gel self-assembly. The problem of dye leakage from open channels is solved by incorporation of hydrophobic groups in the silica matrix. This makes the approach compatible with virtually any dye that can withstand the synthesis. The method is demonstrated using the dye Rhodamine 6G. The obtained 40-nm silica particles are about 30 times brighter than 30-nm coated water-soluble quantum dots. The particles are substantially more photostable than the encapsulated organic dye itself.

Research paper thumbnail of Newly design and synthesis of Ni–Ir–Ru-doped mesoporous silica open-frameworks for admirable electrochemical water-oxidation application

International Journal of Hydrogen Energy

Research paper thumbnail of Bifunctional Periodic Mesoporous Organosilicas with Thiophene and Isocyanurate Bridging Groups

Research paper thumbnail of Synthesis of highly ordered mesoporous benzene-silicas using PEO–PLGA–PEO triblock copolymers

Research paper thumbnail of Biosynthesis of Nanoparticles from Various Biological Sources and Its Biomedical Applications

Molecules, Jun 2, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Direct Solvent-Free Selective Hydrogenation of Levulinic Acid to Valeric Acid Over Multi-Metal (Nixcoymnzalw)-Doped Mesoporous Silica Catalysts

Research paper thumbnail of Carbon‐embedded mesoporous transition multimetal oxide nanospheres for long‐lasting hybrid cells

International Journal of Energy Research, May 20, 2022

Research paper thumbnail of 폴리(비닐리덴 플루오라이드)(PVDF) 막 위에 코팅되는 플루오로에틸렌 비닐 에테르(FEVE) 막의 가교형태에 따른 내자외선성 및 물성 변화 연구

Polymer(Korea), Mar 1, 2017

This study describes the effect of crosslinking types on chemical and physical properties and UV ... more This study describes the effect of crosslinking types on chemical and physical properties and UV resistance of fluoroethylene vinyl ether (FEVE) layer over poly(vinylidene fluoride) (PVDF) in coil-coating. Hexamethoxymethylmelamine (HMMM) of melamine type and hexamethylene diisocyanate (HDI) of isocyanate type were used respectively as crosslinkers of high gloss and transparent FEVE layer on the PVDF coating layer. The evaluation of physical property and UV (UV-B) resistance was processed within ASTM standards. Urethane-reaction group using HDI showed relatively much better stability against UV (UV-B) than melamine reaction group of HMMM, while some physical and chemical resistances were found to be weaker. Also, in spite of the same melamine reaction group, the UV resistance was varied according to the ratio of HMMM cross-linker. From this study, it is expected to enhance weatherability as well as minimize the film deterioration from UV through optimizing crosslinking reaction in FEVE/PVDF double layer coating as a building exterior application.

Research paper thumbnail of Sol-gel synthesis and characterization of mesoporous organosilicas by using block copolymer templates

MRS Proceedings, 2000

Mesoporous organosilicas based on a bridged organosilicate have been synthesized using a triblock... more Mesoporous organosilicas based on a bridged organosilicate have been synthesized using a triblock PEO-PLGA-PEO copolymer containing more hydrophobic poly(DL-lactic acid-coglycolic acid) block and the structural difference between mesoporous organosilicas prepared from PEO-PLGA-PEO and PEO-PPO-PEO block templates is discussed.

Research paper thumbnail of Newly Designed Mesoporous Silica and Organosilica Nanostructures Based on Pentablock Copolymer Templates in Weakly Acidic Media

Nanomaterials, Sep 27, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Research paper thumbnail of Role of block copolymer template for tailoring crystal structure and band gap of titania in mesoporous silica and organosilica particles

Ceramics International, Feb 1, 2020

This work presents the tailoring of distinct titania (titania oxide) (TiO 2) crystal structures i... more This work presents the tailoring of distinct titania (titania oxide) (TiO 2) crystal structures inside the mesoporous silica and organosilica using several different block copolymer templates in acidic aqueous solution with different acidity. Different crystal structures of TiO 2 have been obtained as rutile and anatase phases, mainly depending on the chemical composition of block copolymer templates used in this study. A PEO-PLGA-PEO (EO 17 (L 28 G 7)EO 17 , LGE54) triblock copolymer, as well as typical Pluronic P123 (EO 20 PO 70 EO 20) and F127 (EO 106 PO 70 EO 106) triblock copolymers was employed as structure-directing templates for the sol-gel reaction of silane precursors. As silica and organosilica precursors, tetraethyl orthosilicate (TEOS), 1,2-bis(triethoxysilyl) ethane (BTEE), and 1,4-bis(triethoxysilyl)benzene (BTEB) were utilized with a titanium butoxide precursor. The crystal structure of TiO 2 and its corresponding band gap were investigated using X-ray diffraction (XRD) and ultraviolet-visible spectroscopy (UV-vis) measurements, respectively. Anatase crystalline phase of TiO 2 was found in the mesoporous sample prepared with Pluronic copolymer (i.e. P123 and F127) templates. On the other hand, the rutile phase was developed only in mesoporous samples prepared with an LGE54 PEO-PLGA-PEO triblock copolymer template. It was found the TiO 2 crystal structure is varied mainly depending on the polymer template under various strong acidic conditions. It seems that a thermodynamically more stable rutile phase can be formed using a more hydrophobic LGE54 template which supplies stronger micelle core as a platform. Further, it is known that the incorporation of TiO 2 in mesoporous silica and organosilica samples induces the conduction activity, especially toward the blue light region. Thus, this work can be applied to produce effective blue region semiconductor material with different crystallite structures by tuning the precursors and copolymer templates.

Research paper thumbnail of Synthesis of ordered Ca- and Li-doped mesoporous silicas for H<sub>2</sub> and CO<sub>2</sub> adsorption at ambient temperature and pressure

RSC Advances, 2018

Ca-and Li-doped mesoporous silicas have been prepared successfully using cetyltrimethylammonium b... more Ca-and Li-doped mesoporous silicas have been prepared successfully using cetyltrimethylammonium bromide (CTAB) surfactant in basic media. Sol-gel synthesis and hydrothermal treatment produced highly ordered mesoporous Ca and Li loaded silica particles. The MCM-41 type mesostructures, the porosity, the pore sizes as well as the surface area of Ca-and Li-silicas have been thoroughly investigated using small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and N 2 sorption analysis. Samples prepared with varying amounts of Li and Ca loading have been further analyzed using inductive coupled plasma-atomic emission spectroscopy (ICP-AES) and field-emission scanning electron microscopy (FESEM) with an energy dispersive spectral attachment (EDS), which confirmed quite a large amount of Ca while the amount of Li was not enough. Additionally, H 2 and CO 2 gas uptake studies of these metal-loaded silicas have been carried out using a thermogravimetric analyzer (TGA) at normal temperature (25 C) and pressure (1 atm). H 2 uptake of up to 10 mmol g À1 by Ca-doped silica was recorded. CO 2 and H 2 selectivity were tested with both pure metal-MCM-41 and amine loaded silica using pure N 2 gas and a mixed flow of CO 2 /N 2 and H 2 /N 2. The effect of temperature on CO 2 uptake was also studied using Ca-MCM-41 materials.

Research paper thumbnail of Surfactant-assisted synthesis of ceria–titania-rich mesoporous silica materials and their catalytic activity towards photodegradation of organic dyes

Dalton Transactions, 2017

Figure S1: The plot of C/C 0 versus time (t) for degradation of Rhodamine B dye using only H 2 O ... more Figure S1: The plot of C/C 0 versus time (t) for degradation of Rhodamine B dye using only H 2 O 2. Inset represents a plot of ln(C/C 0) versus time (t) to calculate the rate constant.

Research paper thumbnail of Effect of Morphology and Pore Size of Sulfonated Mesoporous Benzene-silicas in the Preparation of Poly(vinyl alcohol)-Based Hybrid Nanocomposite Membranes for Direct Methanol Fuel Cell Application

Journal of Physical Chemistry B, Jul 1, 2009

Sulfonated mesoporous benzene-silicas were introduced into a poly(vinyl alcohol) (PVA) polymer ma... more Sulfonated mesoporous benzene-silicas were introduced into a poly(vinyl alcohol) (PVA) polymer matrix to act as a barrier for methanol crossover, to prepare composite electrolyte membranes for direct methanol fuel cell applications. Highly ordered 2D hexagonal mesoporous benzene-silicas were prepared using 1,4-bis(triethoxysilyl)benzene (BTEB) organosilica precursor and two kinds of organic templates, such as an octadecyltrimethylammonium bromide (ODTMA) and a Pluronic P123 poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer, to investigate the effect of the morphology and the pore size on the methanol permeability and the proton conductivity of the membranes. The sulfonated mesoporous benzene-silica and PVA were mixed with a sulfosuccinic acid (SSA) cross-linker to improve the membrane stability from mechanical and conductive viewpoints. The physical and chemical characterization of the hybrid electrolyte membranes was performed by varying the contents of sulfonated mesoporous benzene-silicas and SSA. All the hybrid membranes studied showed good performance in lowering the methanol crossover (i.e., approximately 68% reduction in comparison with the Nafion117 membrane), and mesoporous benzene-silica with smaller particle morphology and pores (2-3 nm) was observed to be a more effective additive.