Metal–nitrogen (Co-g-C3N4) doping of surface-modified single-walled carbon nanohorns for use as an oxygen reduction electrocatalyst

Abstract

A cobalt-doped graphitic carbon nitride (g-C₃N₄) polymer was supported on surface-modified single-walled carbon nanohorns (SWCNHs) to produce a new Co-g-C₃N₄ catalyst for the oxygen reduction reaction (ORR). X-ray photoelectron spectroscopy results show that Co–N bonds are formed and that strong electronic coupling occurs between the SWCNHs and Co-g-C₃N₄. The as-fabricated catalysts exhibit reasonable ORR activity, high selectivity, and outstanding electrochemical stability in alkaline media. These results are attributed to the large number of stable Co–N_x active sites, high percentage of pyridinic N and rapid mass transport on the “Dahlia flower”-like SWCNHs surface. The fabricated Co-g-C₃N₄/SWCNHs catalyst has potential for use as a non-precious metal cathodic catalyst in fuel cell applications.