This invention pertains to improved formulations of platinum-molybdenum alloys for use as anode catalysts. These electrocatalysts find utility as a constituent of gas diffusion electrodes for use in fuel cells that operate at less than 180° C. or in applications whereupon hydrogen is oxidized in the presence of carbon monoxide or other platinum inhibiting substances. The new formulations derive unexpected activity through creating highly dispersed alloy particles of up to approximately 300 Å on carbon supports. The desired activity is achieved by carefully controlling the platinum to molybdenum ratio during preparation and judiciously selecting a proper loading of alloy on the carbon support.