“…Other precious metals active toward the HzOR include Rh, ,,, Ru, , Pd, ,,,− Ir, Au, ,,,, Ag, ,,, and their alloys. , On most precious metals, the formation of surface oxides and hydroxides slows down the HzOR, although some oxides are as active as the metal ( e . g ., PtO x and AgO). Thus, high voltages must be avoided in DHFCs to prevent surface oxidation and deactivation.…”