NOVELTY - Carbon nanomaterial manufacture comprises removing a portion(s) of functional groups from a surface of a purified intermediate carbon material by heating the purified intermediate carbon material to greater than 100 degrees C; and/or treating the purified intermediate carbon material with a base to remove functional groups on its surface.    USE - The method is for manufacturing carbon nanomaterial for use as substitute for carbon nanotubes. The carbon nanomaterial is useful e.g. for fuel cells, as a support material for nanoparticle catalysts, and as a particulate filler material added to a polymeric material (e.g. as a replacement for carbon black).    ADVANTAGE - Removing all or a portion of the functional groups from the surface of the carbon nanomaterial gives the carbon nanomaterial beneficial properties including improved dispersibility in hydrophobic materials or organic polymers and excellent electrical conductivity. The carbon nanostructures have superior electrical and material properties compared to carbon nanotubes. When mixed with a polymer, nano structures including carbon nano spheres have reduced electrical resistance compared to polymers that include the same weight percent of carbon nanotubes. Converting residual amorphous carbon to graphite increases the graphitic purity of the carbon nanomaterial. High purity carbon nanomaterials are produced more efficiently using the two step carbonization method compared to attempts to achieve the same level of purity in a single carbonization step. The carbon nanostructures can be substituted for carbon nanotubes, which are typically more expensive to manufacture. They have high porosity and large surface areas. The Brunauer Emmett Teller specific surface area of the carbon nanostructures can be 80-400, preferably 200 m2/g, which is higher than the typical 100 m2/g observed for carbon nanotubes. Even where the method results in carbon nanostructures combined with non-structured graphite, this graphitic mixture (i.e. the carbon nanomaterial) has a surface area greater than carbon nanotubes. Improved diffusion of reactants and/or electrons through the support material improves the efficiency with which substrates and electrons can be transferred to the catalytic surface of the nanoparticles, thus the supported catalysts perform better than nanoparticles supported on traditional supports such as carbon black. Polymer, which incorporates carbon nanostructures having surface functional groups has blistering, while the polymer, which incorporates carbon nanostructures with functional groups removed does not have blistering. Preliminary testing of polymeric materials that were filled with carbon nanostructures indicates that such filled polymeric materials have reduced surface resistance compared to polymers filled with a comparable quantity of carbon black or carbon nanotubes.    DETAILED DESCRIPTION - Carbon nanomaterial manufacture comprises:    (A) forming a precursor mixture comprising a carbon precursor and templating nanoparticles including a catalytic metal;    (B) carbonizing the precursor mixture to form an intermediate carbon material comprising carbon nanostructures, amorphous carbon, and optionally remaining catalytic metal;    (C) purifying the intermediate carbon material by removing a portion(s) of the amorphous carbon and optionally a portion of any remaining catalytic metal, where purified intermediate carbon material has functional groups on its surface; and    (D) removing a portion(s) of the functional groups from the surface of the purified intermediate carbon material by heating the purified intermediate carbon material to greater than 100 degrees C; and/or treating the purified intermediate carbon material with a base to remove functional groups on its surface.    An INDEPENDENT CLAIM is included for a carbon nanomaterial comprising carbon nanostructures having a reduced number of surface functional groups and an increased weight percent of graphitic content, as compared to a carbon nanomaterial manufactured without removing a portion of the surface functional groups or without heating the purified intermediate carbon material.