April 2007

New Hydrogen Lab Equipment Paves the Way for Expanded Research

Photo of researcher in hydrogen lab.
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. 


Photo of researcher using lab equipment.
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.”

Photo of thermogravimetric unit.
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.”   

Photo of researcher using DSC unit.
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. 

Photo of two researchers using the catalyst sprayer.
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.