A device is provided having a cathode capable of catalytically reducing oxygen, an anode capable of catalytically oxidizing hydrogen, and an electrolyte in contact with both the anode and cathode. The cathode and/or anode contain transition-metal phosphates with the formula M.sup.1--M.sup.2P.sub.xO.sub.y. zH.sub.2O, where M.sup.1 is a platinum group metal and M.sup.2 is a transition metal.