Synthesis of Highly Microporous Sulfur-Containing Activated Carbons by a Multistep Modification Process

Abstract

The sulfur-containing activated carbons (SACs) were prepared by CO₂ activation and sulfur impregnation. The sulfur-containing samples were then oxidized in air. The SACs were characterized by N₂ adsorption, elemental analysis, thermogravimetric analysis, X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray diffraction. The CO₂ activation provided precursor carbons with high porosity, which in turn were sulfurized effectively. Oxidation in air at 200 °C enlarged pores and redistributed amorphous sulfur in the hierarchical pores. A typical SAC containing 17.89% sulfur exhibited a surface area of 1 464 m²/g. This work may open up a valid route to prepare highly microporous SACs with high sulfur loading for applications where the presence of sulfur is beneficial.

Keywords

sulfur loading / micropore / CO₂ activation / air oxidation / porous carbons