“There won’t be a revolutionary advance in
fuel cell technology until we understand the
basic mechanisms of these chemical processes
and design better materials to make fuel
cell reactions more efficient.”
20 nm
Nitrogen-doped carbon nanofibers like the one above (dotted with catalyst) help
promote oxygen reduction and could be used to increase the efficiency of fuel
cells. Transmission electron microscopy (TEM) image by: Ganesh Vijayaraghavan.
how a fuel cell works
A fuel cell produces electricity via chemical reactions, rather than by the physical combustion of hydrocarbons, like gasoline. Hydrogen and oxygen are the
fuels that power fuel cells, and the only waste product is water. When operating at full capacity, a fuel cell has the potential to produce 1.2 volts of electricity,
about the same as a AAA battery. Stacks of fuel cells are combined together to create more power.

1 2 3
Diagram of a Fuel Cell • Hydrogen (H
2
) enters anode • Electrons flow from anode • With the help of a catalyst,
(Proton Exchange Membrane) • H
2
broken down by a to cathode, generating oxygen (O
2
), electrons, and protons
catalyst into protons (H
+
) electrical current combine to form water
and electrons (e
-
) • H
+
flows from anode
to cathode
anode cathode
(+) (-)
Carbon Carbon
w/ platinum w/ platinum
& ruthenium catalyst
catalysts
Proton Exchange Membrane
f o c u s o n s c i e n c e 13
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