Preparation of the novel manganese-embedded PAN-based activated carbon nanofibers by electrospinning and their toluene adsorption

Polymer fibers were prepared by using manganese (Mn)-dispersed polyacrylonitrile (PAN)-based composite solutions with various Mn loadings by an electrospinning technique, and then activated carbon nanofibers (ACNFs) were synthesized through the process of stabilization, carbonization and activation using above polymer fibers. The activation was carried out by supplying 30 vol.% steam for 30 min at 800 °C under nitrogen. The average diameter of the Mn-free ACNF or Mn-embedded ones was approximately 250 nm. Our results relating to the pore characteristics show that ACNF having higher specific surface area and larger narrow micropore volume seems to dominate the adsorption of toluene. The toluene adsorption capacity of Mn-free sample was 40 g-toluene/100 g-ACNF, while that of 0.23 wt.% Mn-loaded sample increased to 68 g-toluene/100 g-composite, representing that the specific surface area, micropore volume and average micropore diameter were 1229 m2/g, 0.416 cm3/g and 5.8 Å, respectively. The micropore characteristic suitable for toluene adsorption seems to be managed by combining electrospinning, the addition of Mn particles and the optimal activation condition. This is why electrospinning offers the aligned nano-sized fibers and good dispersion of Mn particles, the embedded Mn used as catalyst for catalytic reactivity and the optimal activation condition prevents mesopore from generating. In the surface chemistry, the oxygen to carbon ratio (O/C ratio) in all samples was similar at approximately 0.1, indicating the non-polarity of the ACNF surface.