| In an effort
to develop alternative energy sources such as fuel cells and solar fuel
from "artificial" photosynthesis, scientists at the U.S. Department of
Energy's Brookhaven National Laboratory are taking a detailed look at electrons
- the particles that set almost all chemmical processes in motion.
Electron transfer plays a vital role
in numerous biological processes, including nerve cell communication and
converting energy from food into useful forms. It's the initial step in
photosynthesis as well, where charges are first separated and the energy
is stored for later use - one of the concepts behind energy production
using solar cells. Understanding and controlling the movement of electrons
through individual molecules also could allow for the development of new
technologies such as extremely small circuits, or help scientists find
catalysts that give fuel cells a much-needed boost in efficiency and affordability.
Three Brookhaven chemists will discuss how these applications are related
to their most recent findings at the 234th National Meeting of the American
Chemical Society.
Platinum is the most efficient metal
electrocatalyst for accelerating chemical reactions in fuel cells. However,
the reactions caused by the expensive metal are slow, and undesired side
reactions often degrade the electrode. In an effort to find an affordable
alternative with high activity and stability, Brookhaven chemist Ping Liu
and her research group are introducing ruthenium oxide to the electronic
system. By carefully forming just one thin layer of platinum on a ruthenium-oxide
surface, Ping has calculated that the oxidation-reduction reaction (the
driving force for fuel cells) happens almost as quickly as with a pure
platinum catalyst, while using much less of the pricey metal and preventing
its dissolution.
"Theoretically, when there's one
monolayer of platinum on ruthenium-oxide, it has very close activity to
pure platinum," Liu said. "It's not quite as good, but it's very close.
This surface should be one of the alternatives we consider for oxidation-reduction
catalysts."
Future research plans include looking
for ways to modify the surface, adding other elements or metals, and further
reducing the cost by searching for a surface material less expensive than
ruthenium oxide.
The research by Muckerman and Liu
is funded through the U.S. Department of Energy's Hydrogen Program, which
implements the President's Hydrogen Fuel Initiative, a five-year program
that began in 2003 to sponsor research, development, and demonstration
of hydrogen and fuel cell technologies. Specifically, the funding derived
from DOE's Office of Basic Energy Sciences within the Office of Science,
which also funds Newton's work.
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