Effect of acid treatment on structure and morphology of carbons prepared from pyrolysis of polyfurfuryl alcohol

Furfuryl alcohol (FA) was polymerized in aqueous solutions consisting of polyvinyl pyrrolidone (PVP) as a surfactant together with hydrochloric acid, phosphoric acid, or acetic acid as a catalyst, respectively. The polymerization degree of FA and the resulting structural difference after carbonization were examined. Experiments revealed that the presence of acids does indeed promote polymerization of FA, leading to a reduced defect population and an eventual formation of a more ordered structure in the carbonized products. This is particularly pronounced when hydrochloric acid was used as a catalyzer, forming “nonstick” polyfurfuryl alcohol (PFA) particles with a diameter ca. 0.5–1 μm. The polymeric particles were then converted into microporous carbon spheres with a specific surface area of 297 m2/g when calcined at 600 °C in argon atmosphere. On the contrary, FA in the rest of catalyst systems showed aggregated form with a pronouncedly reduced specific surface area ranging from 0.3 to 5.2 m2/g.