▎ 摘　　要

NOVELTY - A palladium-tin-cobalt ternary alloy nanocatalyst preparing method involves ultrasonically dispersing a nitrogen-doped graphene carrier into an ethanol solution and stirring a ratio of palladium salt, tin salt and cobalt salt to obtain mixture. The mixture is added with nitrogen-doped graphene ethanol solution. The palladium-tin-cobalt ethanol mixed solution is stirred with sodium borohydride, followed by centrifugally separating the ethanol mixed solution containing palladium-tin-cobalt ternary metal alloy to obtain a precipitate, washing the precipitate and drying to obtain a final product. USE - Method for preparing a palladium-tin-cobalt ternary alloy nanocatalyst for catalyzing an oxygen reduction reaction in a lithium-air battery and a fuel cell. ADVANTAGE - The method enables preparing a palladium-tin-cobalt ternary alloy nanocatalyst with better effects of reducing the nano noble metal palladium in the catalyst dosage, improving the catalytic activity, increasing the interaction of ternary alloy nanoparticles and improving the circulating stability. DETAILED DESCRIPTION - A palladium-tin-cobalt ternary alloy nanocatalyst preparing method involves ultrasonically dispersing a nitrogen-doped graphene carrier into an ethanol solution for 20-40 minutes to obtain nitrogen-doped graphene ethanol solution and mixing a ratio of palladium salt, tin salt and cobalt salt under stirring to obtain mixture. The mixture is added with nitrogen-doped graphene ethanol solution to obtain a solution. The pH value of the solution is adjusted to more than 11 to obtain a palladium-tin-cobalt ethanol mixed solution. The palladium-tin-cobalt ethanol mixed solution is stirred with sodium borohydride for 1-4 hours and a palladium ion, tin ion and cobalt ion are completely reduced to palladium-tin-cobalt (PdxSnyCoz) ternary metal alloy to obtain an ethanol mixed solution containing palladium-tin-cobalt (PdxSnyCoz) nano ternary metal alloy, followed by centrifugally separating the ethanol mixed solution containing palladium-tin-cobalt (PdxSnyCoz) ternary metal alloy to obtain a palladium-tin-cobalt (PdxSnyCoz) nano-precipitate of ternary metal alloy, washing the precipitate to neutral, freezing and drying to obtain a palladium-tin-cobalt ternary alloy nano catalyst, where x, y and z are mole fraction. An INDEPENDENT CLAIM is also included for a palladium-tin-cobalt ternary alloy nanometre catalyst.