▎ 摘　　要

NOVELTY - A nanoparticle composite oxygen-reducing (ORR) catalyst comprises cobalt/cobalt oxide nanoparticles on a graphene support. USE - Nanoparticles composite oxygen-reducing catalyst is used for promoting the oxygen reduction reaction (claimed) in electrochemical cell and battery. ADVANTAGE - The nanoparticles composite oxygen-reducing catalyst has excellent catalytic characteristics and stability, and provides battery having excellent cyclic characteristics and stability. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) formation of nanoparticle composite oxygen-reducing catalyst, which involves combining a hexane dispersion of as-prepared cobalt nanoparticles and a dimethylformamide solution containing graphene at room temperature, sonicating the combined solutions at room temperature, precipitating the product, dispersing the product in butyl amine and stirring at ambient temperature, precipitating the metal nanoparticles on graphene catalyst by centrifuging and forming an oxide on the nanoparticles in air at a designated temperature and a time period; and (2) Usage of graphene-cobalt/cobalt oxide composite catalyst for promoting the oxygen reduction reaction, which involves positioning the composite catalyst to reduce oxygen in an electrochemical cell containing oxygen in potassium hydroxide.