▎ 摘　　要

NOVELTY - Powder mass of multiple porous graphene balls, comprises multiple graphene sheets having a catalyst, in a form of nanoparticles or coating having a diameter or thickness from 0.3-10 nm, bonded to or supported by graphene sheet surfaces, where porous graphene balls having a diameter from 0.1-100 mu m, a physical density from 0.01-1.7 g/cm3, and a specific surface area from 50-3,000 m2/g and where the catalyst is in an amount from 0.01-50% by weight of the total graphene ball weight. USE - The graphene ball is useful in gas storage for underground supply systems. ADVANTAGE - The graphene ball: significantly increases the capacity of gas species storage of the graphene-based materials; is an economical and simple approach, is safe and portable; and solves the problem of explosion hazard. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for (1) a gas storage device containing the powder mass as a gas-absorbing, gas-adsorbing, gas-capturing, or gas-storing medium to store a gas species in it; and (2) a method of producing the powder mass, comprising either (a) providing a suspension of multiple graphene sheets dispersed in a liquid medium where a catalyst or a catalyst precursor is dispersed or dissolved in the liquid medium or where the catalyst is pre-deposited on surfaces of the graphene sheets in a form of nanoparticles or coating, and (b) dispensing the suspension into multiple micro-droplets and thermally or chemically converting the micro-droplets into the mass of porous graphene balls or (A) providing a suspension of multiple graphene sheets dispersed in a liquid medium, (B) dispensing the suspension into multiple micro-drop- lets and removing the liquid from the micro-droplets to form porous micro-droplets comprising multiple graphene sheets and pores, and (C) impregnating the pores with a catalyst or a catalyst precursor and thermally or chemically converting the catalyst precursor to the catalyst to obtain the multiple porous graphene balls. DESCRIPTION OF DRAWING(S) - The drawing shows a flowchart illustrating the method for two processes that can be used to produce the porous graphene balls for gas storage. Porous graphene ball structure (1)