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Senior research scientist Clovis Linkous,
an expert on hydrogen production, is very excited
to be working with FSEC's new hydrogen and fuel cell
equipment. |
One of the Center’s fastest-growing and most popular research
programs is the hydrogen and fuel cell area, topics that are in the
news often for their promise in providing power for both our transportation
energy needs and for our homes and other buildings.
A growing research program has enabled FSEC to buy some specialized
new equipment that will assist researchers with better and quicker
results. “We’ve got a few new pieces of equipment
in particular that we’re especially excited about,” said
Clovis Linkous, a senior research scientist in the hydrogen division.
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Darlene Slattery, a senior research
chemist, uses the PCT apparatus to evaluate
pressure, composition and temperature characteristics
of a hydride material used for storing hydrogen. |
The newest item in the Hydrogen Lab is the PCT apparatus – a
machine that measures the hydrogen pressure in equilibrium with a
hydrogen-containing substance as a function of temperature and residual
hydrogen content. The graphical output of this data is the PCT
(pressure, composition, temperature) characteristic of the material. “Darlene
Slattery of the Hydrogen R&D Division has overseen the acquisition
and installation of the PCT instrument, the first to be placed by
this vendor, Hiden Analytical, in the U.S.,” he noted. Linkous
explained that the machine will be very valuable to the researchers
in their work on storage of hydrogen, especially in projects involving
fuel cell vehicles. “You need to know how much hydrogen
exists in the gas phase and how much is held in the solid state by
the hydriding metal at a given temperature. Otherwise, you won’t
be able to store and deliver the hydrogen in a controlled manner. The
PCT instrument will replace the current method of going through a
sequence of tedious manual measurements. Now we’ll get
an automatic acquisition of the PCT curve and be able to evaluate
hydride materials much quicker than we can now – in just a few
hours instead of a few days.”
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The Thermogravimetric/Differential
Thermal Analyzer weighs and heats solid or liquid samples
at the same time, giving researchers quicker and more
accurate results. |
An instrument that the Hydrogen R&D Division has had in the lab
for some time but has recently been upgraded is the Perkin-Elmer Diamond
Thermogravimetric/Differential Thermal Analyzer, or TG/DTA. Solid
or liquid samples are weighed and heated at the same time. “Any
physical or chemical transformation that results in gas evolution,
whether it is hydrogen, water vapor, or whatever, can then be quantified
as to the amount of material that evolved and the threshold temperature
at which it occurred,” explained Linkous. “This
is important information for many chemical systems under study, including
hydrogen storage by metal hydrides, water absorption by inorganic
oxides, and decomposition temperatures of organic polymers. The
upgrade, overseen by Nahid Mohajeri of the Hydrogen R&D Division,
consists of an attachment that allows sampling of the off-gas with
a mass spectrometer, an existing instrument within the Hydrogen Lab’s
analytical arsenal. The mass spectrometer can confirm the identity
of a gas by measuring its molecular weight.”
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Nahid Mohajeri, a research chemist,
loads polymer membrane samples on the DSC to monitor
phase transitions as a result of heat flow. |
A new complementary instrument to the TG/DTA is the Perkin-Elmer
Diamond Cryofill Differential Scanning Calorimeter, or DSC. A
sample is heated once again, except this time the amount of energy
required to sustain the temperature increase is closely monitored. When
transformations occur in the test chamber, the energy released or
absorbed in each case is measured. Such energy balances become
important when calculating how much energy is required to release
hydrogen from a storage material, or how much energy must be dissipated
when the hydrogen is stored. While most DSC instruments can
only initiate scans at room temperature and above, this one has a
cooling chamber for cryogenic fluids like liquid nitrogen, so that
thermodynamics of reactions that occur at very cold temperatures can
be studied.
Another unique piece of equipment now in FSEC’s lab is an automated
catalyst deposition set-up using a Bislide® positioning system. The
set-up is used to uniformly deposit catalyst inks onto the
polymer electrolyte membrane of a fuel cell. Active areas can
be varied from
5 to 400 cm2. Linkous noted that “This is a
home-built system put together by Vishal Mittal, a research engineer
in the Hydrogen Division.
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Assistant professor Nicoleta Sorloaica-Hickman
instructs graduate student Bo Li how to manufacture
membrane-electrode assemblies for Proton Exchange Membrane
Fuel Cells using the new catalyst sprayer. |
Now FSEC is able to build catalyst layers directly
onto the membrane electrolyte. It enables us to make membrane-electrode
assemblies -- the sandwich comprised of fused electrode-electrolyte-electrode
layers -- according to our own specifications, as opposed to being
forced to deal with a few commercial vendors.”
Equipment like this will help FSEC researchers as they continue
looking into the development of hydrogen and fuel cell technologies. You
might not see this equipment, but you’ll certainly be seeing the
results it helps make possible.