▎ 摘　　要

NOVELTY - A three-dimensional porous nickel oxide-and-nitrogen-doped graphene quantum dot composite material is prepared by using nickel foam as a substrate, oxidizing and etching large number of micron-sized holes on the nickel foam surface, retaining the three-dimensional porous structure of nickel foam, and forming nickel oxide-and-nitrogen-doped graphene quantum dot composite on the surface of nickel foam. USE - Three-dimensional porous nickel oxide-and-nitrogen-doped graphene quantum dot composite material used as catalyst in electrocatalytic oxygen evolution reaction (claimed). ADVANTAGE - The three-dimensional porous nickel oxide-and-nitrogen-doped graphene quantum dot composite material has excellent electrocatalytic performance, and effectively reduces the electrolytic oxygen evolution reaction overpotential. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of three-dimensional porous nickel oxide-and-nitrogen-doped graphene quantum dot composite material, which involves (i) ultrasonically cleaning nickel foam with ethanol and water for 30 minutes, placing in a vacuum oven at 40 degrees C, drying, (ii) using biomass watermelon pulp as carbon source and nitrogen source, hydrothermally processing, dialyzing, pyrolyzing, microwave synthesizing, and purifying to obtain aqueous nitrogen-doped graphene quantum dot solution, (iii) mixing 5 ml purified aqueous nitrogen-doped graphene quantum dot solution and 20 ml etchant trioctylphosphine oxide solution, adding into a polytetrafluoroethylene-lined reactor, adding clean nickel foam, hydrothermally treating at 180 degrees C, and in-line growing nickel oxide and nitrogen-doped graphene quantum dot composite on the nickel foam surface.