  The large-scale practical application of fuel cells in hydrogen economy is
possible only with a dramatic reduction of the cost coupled with a significant
improvement of the electrocatalytic properties of the electrodes. This goal can
be achieved through a rational design of new materials, which requires
understanding of the microscopic mechanisms underlying the electrocatalysis. We
discuss some applications of the density functional theory to this problem
using using alloying of Ru with Pt as the case in point. We provide some
details for Pt islets on Ru nanoparticles, for which our calculations explain
the high CO tolerance observed for such anodes of the fuel cell. We also
discuss energetics responsible for the stability of these islets on the
nanoparticles.
