NOVELTY - Preparing doped single graphene sheets, involves: a) providing graphite; b) oxidizing the graphite to non-electrically conductive graphite oxide; c) exfoliating the graphite oxide in a solvent; d) depositing nanoparticles selected from metals and metal oxides on the product of (c); and e) reducing the product of (d) to electrically conductive single graphene sheets.    USE - For preparing doped single graphene sheets useful in an energy conversion/storage device selected from a fuel cell, battery, particularly a lithium ion battery, super capacitor, ultra super capacitor, or a solar cell (claimed).    ADVANTAGE - The process is relatively less expensive, and it produces single graphene sheets with a high surface area of at least 1500 m2/g that provides opportunities for storage and conversion of energy.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) storing hydrogen gas involving: subjecting hydrogen gas to a conductive single graphene sheet having nanoparticulate metal or metal oxides doped on it;    (2) a composition of matter which is expanded graphite nanoplatelets (xGnP) decorated with metal or metal oxide nanoparticles;    (3) an apparatus assembly for providing expanded intercalated graphite in a gaseous atmosphere using chemical treatment, comprising: an apparatus for expanding graphite selected from microwave and radiofrequency; a feed unit for feeding the intercalated unexpanded graphite into an enclosed chamber; sorting unit in the chamber for differentiating between the expanded graphite and the intercalated unexpanded graphite; exit unit from the chamber for receiving the expanded graphite from the sorting unit; and unit for depositing nanoparticles selected from metals and metal oxides on the expanded graphite; and    (4) manufacturing expanded intercalated graphite decorated with metal or metal oxide nanoparticles, involving: providing intercalated graphite; expanding the intercalated graphite using an apparatus selected from microwave and radiofrequency; feeding the expanded intercalated graphite into an enclosed chamber containing gas; sorting the material in the chamber to provide intercalated expanded graphite; moving the intercalated expanded graphite from the chamber; and depositing nanoparticles selected from metals and metal oxides on the surface of the expanded intercalated graphite.