Sulphur as medium: Directly converting pitch into porous carbon

Abstract

Pitch is an abundant and cheap byproduct, however, the upgrading of pitch into high value materials has been rarely explored. To convert the chemically inert pitch into porous carbon, activating agents are generally required while the high cost of current approach makes the commercialization of pitch-derived porous carbon difficult. Considering the hydrophobic solubility, wide temperature range as liquid, favorable trend to form organized clusters/aggregations and low boiling point for easy evaporation at high temperature, element sulfur is introduced as reaction medium to dissolve and carbonize pitch into carbon material. After the evaporation and recovery (~95 wt%) of gaseous sulfur, plenty of pores (589 m2g−1) together with element sulfur (up to ~18 wt%) are directed into carbon materials. The S-doped carbon exhibits good catalytic activity in selective oxidation of aromatic sulfides (Conv. > 90% Sel. > 90%). Moreover this sulfur-mediated method applies to raw pitches from coal-tar to petroleum and can scale up to kilogram level.