NOVELTY - A low-temperature fuel cell electrocatalyst comprises graphene oxide as carrier dispersed on surface of palladium-platinum polyhedral nanocrystal. The palladium-platinum polyhedral nanocrystal is tetrahedron, octahedron and dodecahedron-shaped nanocrystal having size of 5-30 nm.    USE - Low-temperature fuel cell electrocatalyst.    ADVANTAGE - The method does not need template and it has simple technique and easy operation. The electrocatalyst shows catalytic activity closer to platinum on carbon catalyst, and it has platinum content lower than platinum on carbon, and significantly better performance against methanol poisoning than platinum on carbon catalyst.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of electrocatalyst comprising:    (A) mixing 2-100 mL palladium precursor solution containing 10 g/L palladium element with reducing solvent at volume ratio of 1:10, magnetically stirring at 100-300 revolutions/minute, adding 25 wt.% concentrated aqueous ammonia, and stirring until solution turns from light yellow to colorless to obtain first solution;    (B) dissolving platinum precursor containing 10 g/L platinum element in same reducing solvent, magnetically stirring at 100-300 revolutions/minute, adding first solution at palladium and platinum molar ratio of 9:1-1:1, stirring, adding 25 wt.% concentrated aqueous ammonia, and adjusting pH to greater than 10 to obtain second solution;    (C) oxidizing graphene through Hummers method for 1-4 times to obtain 1 g/L graphene oxide, dispersing in solvent, ultrasonically agitating, adding second solution, stirring for 24-72 hours, and ultrasonically dispersing for 2-12 hours;    (D) transferring 0.1-5 L reaction solution into hydrothermal reaction kettle, forced air-oven reacting or vacuum-oven reacting to 80-180 degrees C for 2-8 hours, and cooling; and    (E) magnetically stirring at 300-600 revolutions/minute, adding reducing agent, stirring for 0.5-5 hours, filtering solid, centrifuging, washing with ethanol and water alternately for 4-6 times, and vacuum oven-drying.    The mass ratio of platinum, palladium and graphene oxide is 1:4-1:1. The mass ratio of reducing agent and graphene oxide is 1:1-3:1.