A membrane electrode assembly includes an anode including a hydrogen
oxidation catalyst; a cathode; a membrane disposed between the anode and
the cathode; and a peroxide decomposition catalyst positioned in at least
one position selected from the group consisting of the anode, the
cathode, a layer between the anode and the membrane and a layer between
the cathode and the membrane wherein the peroxide decomposition catalyst
has selectivity when exposed to hydrogen peroxide toward reactions which
form benign products from the hydrogen peroxide. The peroxide
decomposition catalyst can also be positioned within the membrane. Also
disclosed is a power-generating fuel cell system including such a
membrane electrode assembly, and a process for operating such a fuel cell
system.