Formation of nanographite using GaPO₄-LTA as template

An attempt was made to prepare nanographite with uniform size by pyrolysis of 4-methyl pyridine (MPy), which is the structure-directing agent for the formation of GaPO₄-LTA single crystals, in the GaPO₄-LTA framework at 760 °C. The as-prepared nanographite has been examined by Raman spectroscopy, transmission electron microscopy (TEM), electron spin resonance (ESR) and magnetization characterizations. The TEM image shows that the size of individual nanographite particles is about 7 nm, and it is proved that there are spins of sp²-type (π-type) radical electrons localized on the zigzag edge sites of the nanographite. The magnetic susceptibility of the nanographite shows crossover from a high-temperature diamagnetic to a low-temperature paramagnetic behavior, in good agreement with the theoretical expectation.