One-pot synthesis of activated porous graphitic carbon spheres with cobalt nanoparticles

Abstract

Nitrogen doped porous graphitic carbon spheres have been extensively studied for various applications such as adsorption, catalysis, energy storage, and drug delivery due to their unique properties such as high surface area, tunable porosity, and importantly their low cost. Among many strategies available for the synthesis of graphitic carbons, catalytic graphitization is widely explored due to its industrial feasibility. Additionally, activated carbons with fine micropores are vastly studied for CO2 capture at ambient conditions. In this case, in-situ activation of carbon spheres is promising because it combines both carbonization and activation in a single-step. This study is focused on the development of in-situ activated graphitic carbon spheres (AGCSs) by adopting a one-pot modified Stӧber-like synthesis and restricting temperature treatment to a single step. Cobalt acetate and potassium citrate were added in the synthesis, where the former acted as a graphitization catalyst, while the latter acted as an activator. The resulting carbon spheres were characterized by scanning and transmission electron microscopy, nitrogen adsorption, thermogravimetry, elemental analysis, infrared spectroscopy, and X-ray diffraction. These spheres possess high volumes of ultramicropores in addition to graphitic and magnetic properties. AGCSs were able to adsorb about 5 mmol·g−1 of CO2 at 0 °C and 1 bar.