Few-step synthesis, thermal purification and structural characterization of porous boron nitride nanoplatelets.

Hexagonal boron nitride (h-BN) nanoplatelets with ~ 99 wt.% purity, 900 to 2000 nm particle width, 30 to 90 nm particle thickness, ~ 213 m 2 /g specific surface area (SSA), ~ 66% micropore SSA and ~ 0.85 nm average pore size were synthesized in a powder form using H 3 BO 3 and CO(NH 2 ) 2 as precursors followed by consecutive thermal treatments under inert and oxidized atmospheres. Thermal gravimetric analysis (TGA) combined with differential scanning calorimetry (DSC), under synthetic air-flow and up to ~ 1300 °C, were employed to evaluate both purity and oxidation resistance of the product directly upon its synthesis. The h-BN powder was collected at the stage of its highest purity which, based on TGA-DSC data, corresponded to an additional heat treatment up to ~ 700 °C. The active oxidation seems to occur in the temperature range between ~ 860 and ~ 1000 °C, followed by formation of B 2 O 3 in the final residue. Subsequently, the purified h-BN powder was extensively characterized for its structure, morphology and porosity using X-ray diffraction, scanning electron microscopy and nitrogen gas adsorption/desorption measurements at 77 K, respectively. As briefly discussed, purity and SSA seem to have a crucial role in the thermal stability and oxidation resistance of BN materials in general. [ABSTRACT FROM AUTHOR]