Carbide-derived carbon obtained via bromination of titanium carbide: Comparative analysis with chlorination and hydrogen storage studies

Carbide-derived carbons (CDCs) are synthesized from TiC micropowder via gas phase bromination at the temperature range of 350-1150 degrees C. The resultant carbon materials demonstrate high specific surface areas and micropore volumes of up to 1745 m(2) g(-1) and 0.64 cm(3) g(-1) respectively. Successful bromination of TiC in a wide temperature range permitted the first in-depth comparative study of CDCs produced by Br-2 and Cl-2 thermochemical extraction. Although minor, some structural differences between TiC-CDCs obtained via bromination and chlorination reactions are observed. It is concluded that it is not the size of halogen and evolving titanium halide molecules but the reactivity of the halogen that affects the microporosity of TiC-CDCs. The structural similarity of materials obtained via Br-2 and Cl-2 extraction proves that the extractive step does not determine the final structure of CDCs. Cryogenic high-pressure hydrogen storage studies show that the maximum excess hydrogen uptake of TiC-CDCs strongly correlates to the volume of micropores below 1.75 nm in size.