Selective-combustion purification of bulk carbonaceous solids to produce graphitic nanostructures

We demonstrate the use of simple thermal oxidation processes to purify bulk carbon composites produced from thermosets, which were formulated from precursor compositions containing a melt-processible organometallic Ni catalyst in an excess of carbon source. The as-pyrolyzed carbonaceous solids comprise Ni nanoparticles and interpenetrating amorphous and graphitic carbon domains, where the fraction of crystalline carbon is determined primarily by the carbonization temperature. We exploit the adventitious amorphous carbon phase as a pore-forming agent, which is subsequently removed by selective combustion, exposing the embedded graphitic nanostructures and associated metal catalyst nanoparticles, while still retaining the macroscopic dimensions of the initial thermoset polymeric solid. The pore network formed by removal of the amorphous carbon facilitates the mass transport of gas-phase molecules, such as ammonia, to the internal surfaces of the purified carbon solid. The ability to produce nanostructured graphitic carbons in bulk solid forms using simple processing methods will facilitate their development for applications ranging from electrochemical energy storage to gas sorption/filtration.