Specifically, they're looking for ways to use gold to prevent the destruction of platinum in the chemical reactions that take place in fuel cells. Brookhaven chemist Radoslav Adzic will describe this research during the 233rd National Meeting of the American Chemical Society at 2 p.m. Central Time (3 p.m. Eastern Time) on Tuesday, March 27, 2007, in room S405A, Level 4, at McCormick Place South, Chicago, Illinois.
Platinum is the most efficient electrocatalyst for accelerating chemical reactions in fuel cells. However, in reactions during the stop-and-go driving of a fuel-cell-powered electric car, the platinum dissolves. In accelerated tests, as much as 45 percent of the catalyst can be lost during five days. "Platinum is by far the best single component catalyst for the oxygen reduction reaction, and we have to find a way to protect it," Adzic said. Under lab conditions that imitate the environment of a fuel cell, Adzic and a team of Brookhaven researchers, including Junliang Zhang, Kotaro Sasaki, and Eli Sutter, added gold clusters to a platinum electrocatalyst, which kept it intact during an accelerated stability test that simulates stop-and-go driving in an electric car.
The details: A fuel cell converts hydrogen and oxygen into water and, as part of the process, produces electricity. Hydrogen is oxidized at the device's anode (the terminal where current flows in) when electrons are released and hydrogen ions are formed; the released electrons supply current for an electric motor. These electrons flow to the cathode (the terminal where current flows out) to reduce oxygen, and in a reaction with hydrogen ions, water, the only byproduct of a fuel cell reaction, is produced. Platinum electrocatalysts are used to speed up the oxidation and reduction reactions involved in this process, but as a result, they, too, are oxidized (lose electrons) and dissolve.
In the unique method used at Brookhaven, researchers place gold on carbon-supported platinum nanoparticles by displacing a single layer of copper and subject it to several sweeps of voltage. The copper is needed to reduce the charged gold particles to neutral atoms; it then conveniently forms a monolayer of platinum by an adsorption process, the binding of molecules or particles to a surface. Using x-rays as probes at Brookhaven's National Synchrotron Light Source, a scanning transmission microscope at Brookhaven's Center for Functional Nanomaterials, and electrochemical techniques in the laboratory, the scientists can show that less platinum is oxidized with this method. As predicted, during laboratory testing, the platinum electrocatalyst remains stable when under conditions mimicking stop-and-go driving conditions. Next, researchers will test the catalyst in real fuel cells at the DOE's Los Alamos National Laboratory in New Mexico.
"The very promising properties of fuel cells have been known for many decades," Adzic said. "But it's only now that we can look at the activities and qualities of the catalysts and find something stable enough to be used in cars or residential applications."
Karen McNulty Walsh | EurekAlert!
‘Farming’ bacteria to boost growth in the oceans
24.10.2016 | Max-Planck-Institut für marine Mikrobiologie
Calcium Induces Chronic Lung Infections
24.10.2016 | Universität Basel
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
24.10.2016 | Earth Sciences
24.10.2016 | Life Sciences
24.10.2016 | Physics and Astronomy