research & development
New Catalyst Makes Fuel Cells More Efficient
Dr. José E. Barranco focused on the need for new catalysts when he presented his PhD thesis, Development of New Metallic Materials of an Amorphous Nature for use in direct methanol fuel cells, at the University of the Basque Country (UPV/EHU) in Spain. After investigating the composition of numerous metals, Barranco made alloys that reduce the platinum to 1%. Composed of elements such as nickel, niobium, antimony or ruthenium, these alloys efficiently convert molecules of carbon monoxide (CO) into carbon dioxide (CO2). Being gaseous, the CO2 does not adhere to the catalyst which in the long term favors the catalytic process.
This means that the methanol fuel cell will emit a small quantity of CO2 which, according to Barranco, is easily tolerable by nature given that this can be incorporated into the photosynthesis cycle of plants. An American Methanol Institute study forecasts that by 2020 there will be 40 million cars powered by methanol fuel cells, reducing the CO2 emissions by 104 million tons.
Once the suitable catalyst was found, Barranco set out to increase its efficiency. The conclusions of his thesis point to the fact that, if the platinum alloy is structured amorphously, its electrical conduction properties are enhanced and it undergoes less corrosion (advantages for the medium in which it has to operate). Moreover, it has an operational capacity 80-100 times greater than platinum in a crystalline structure. Amorphous materials are those with a disordered molecular structure and which, in this case, are obtained by the sudden cooling of metal alloys.
Mini-Helicopters with Fuel Cells
ScienceDaily reports that together with colleagues at the Technical University of Berlin, researchers from the Fraunhofer Institute for Reliability and Microintegration IZM in Berlin have developed a fuel cell that weighs only 30gm and has an output of 12W.
The high power density of 400W/kg has so far only been achieved in considerably larger systems weighing several hundred grams. The cell is light enough to power a 20cm helicopter. It is being developed by the participants in an EU project, and will be used in future for missions such as locating victims trapped in fallen buildings, monitoring traffic or investigating tracts of land that have been contaminated by chemical accidents.
"We use very thin, planar fuel cells," explains IZM team leader Dr. Robert Hahn. "We have replaced the metal plates by lightweight plastic spacers."
The researchers have no need for an additional pump to provide an adequate air supply. The wind generated by the helicopter's rotor blades goes directly into the air vents. Since the helicopter always needs about the same amount of energy to stay in the air, the reactor always has to produce a consistent quantity of hydrogen. The researchers have already built a prototype of the lightweight fuel cell.
