Preparation of sulfur-doped graphite by solid-state microwave method: The effect of reaction conditions on the sulfur-doping process

The high-quality sulfur-doped graphite (SGi) was prepared from concentrated sulfuric acid-graphite intercalation compounds (H2SO4-GICs) by solid-state microwave irradiation, where H2SO4 was the sulfur (S) source and S-doping occurred within a minute. The preparation of H2SO4-GICs was a key step for S-doping and exfoliation process. Notably, it was found that S-doping was influenced by the dosage of H2SO4, where the lower dosage of H2SO4 was beneficial for the S-doping. The exfoliation efficiency was greatly affected by the temperature and dosage of oxidant, where lower temperature and lower dosage of KMnO4 guaranteed efficient exfoliation.