Electrochemical Capacitance of Nitrogen-Containing Nanocarbons Prepared Using Porous Anodic Alumina Template

Abstract

Nanocarbons with brush-type morphology have been prepared by liquid phase carbonization of poly(acrylamide) (PAA) or poly(vinylchloride) (PVC) in pores of template. The template used is dc etched aluminum foil that is further anodized in sulfuric acid electrolyte. The nanocarbons derived from PAA contain nitrogen, whose content decreases with increasing heat treatment temperature. At each heat treatment temperature, the specific surface area as well as pore structure is similar for both the nanocarbons derived from PAA and PVC. Nevertheless, the markedly large electrochemical capacitance, measured in 1 mol dm⁻³ sulphuric acid, is obtained for the PAA-derived nanocarbons, compared with that from PVC, due to pseudocapacitance arising from nitrogen species in the former nanocarbons. Despite the specific surface area of less than 250 m² g⁻¹, the PAA-derived nanocarbons reveal the capacitance as large as ∼130 F g⁻¹. The capacitance per specific surface area is found to increase almost linearly with the content of nitrogen. It is also found that the capacitance per specific surface area of the nanocarbons with the brush-type morphology is larger than that of the carbon nanofilaments prepared similarly using a template of porous anodic alumina on plain aluminum foil.