(319d) Molecular Optimization of Multiply-Functionalized Mesoporous Films with Ion Conduction Properties
AIChE Annual Meeting
2011
2011 Annual Meeting
Nanomaterials for Energy Applications
Nanomaterials for Hydrogen Production and Fuel Cells II
Tuesday, October 18, 2011 - 1:45pm to 2:05pm
The
performance and stability of hydrogen fuel cells could be improved by operation
at elevated temperatures (>100 °), which would provide faster kinetics of
the anode and cathode reactions, higher permissible CO levels in the hydrogen
feed stream, more effective water management, and efficient heat recovery.
However, current
industrial proton exchange membranes based on perfluorinated sulfonic acids (PFSAs, e.g., NafionTM)
limit hydrogen
fuel
cell
operation
to relatively
low temperatures (<100 °) and high humidities, which lead otherwise to reduced
proton conductivities as the hydrophilic ion-conducting channels dehydrate and become
disconnected. We have developed a
novel proton-exchange-membrane material based on PFSA-functionalized
nanostructured aluminosilica for the operation of hydrogen fuel cells at
elevated temperatures (>100 °) and in dry environments. These
organic-inorganic hybrid membranes are designed to maintain their
proton-conducting channels by exploiting their robust aluminosilica frameworks
with interconnected pores that remain open, independent of the extent of
hydration, thus sustaining proton-conduction properties at elevated
temperatures and low humidities. The mesoporous membranes are synthesized by using block
copolymers to direct the
formation of cubic mesostructured silica films, which are subsequently functionalized
with aluminosilica and PFSA species. Molecular, mesoscopic, and macroscopic
properties of the multiply-functionalized films have been characterized and
correlated at each stage of the syntheses by NMR, small-angle X-ray and neutron
scattering, transmission electron microscopy, elemental analysis, adsorption,
and conductivity measurements. The resulting materials have a novel combination
of stable mesopores, high hydrophilicities, and maintain high proton
conductivities at elevated temperatures and under low humidity conditions.
performance and stability of hydrogen fuel cells could be improved by operation
at elevated temperatures (>100 °), which would provide faster kinetics of
the anode and cathode reactions, higher permissible CO levels in the hydrogen
feed stream, more effective water management, and efficient heat recovery.
However, current
industrial proton exchange membranes based on perfluorinated sulfonic acids (PFSAs, e.g., NafionTM)
limit hydrogen
fuel
cell
operation
to relatively
low temperatures (<100 °) and high humidities, which lead otherwise to reduced
proton conductivities as the hydrophilic ion-conducting channels dehydrate and become
disconnected. We have developed a
novel proton-exchange-membrane material based on PFSA-functionalized
nanostructured aluminosilica for the operation of hydrogen fuel cells at
elevated temperatures (>100 °) and in dry environments. These
organic-inorganic hybrid membranes are designed to maintain their
proton-conducting channels by exploiting their robust aluminosilica frameworks
with interconnected pores that remain open, independent of the extent of
hydration, thus sustaining proton-conduction properties at elevated
temperatures and low humidities. The mesoporous membranes are synthesized by using block
copolymers to direct the
formation of cubic mesostructured silica films, which are subsequently functionalized
with aluminosilica and PFSA species. Molecular, mesoscopic, and macroscopic
properties of the multiply-functionalized films have been characterized and
correlated at each stage of the syntheses by NMR, small-angle X-ray and neutron
scattering, transmission electron microscopy, elemental analysis, adsorption,
and conductivity measurements. The resulting materials have a novel combination
of stable mesopores, high hydrophilicities, and maintain high proton
conductivities at elevated temperatures and under low humidity conditions.