Improving ORR Activity of Nitrogen-Doped Carbon Catalysts via Washing PANI-iron Coordination Precursor with ethanol

Effectively improving catalytic activity of nitrogen (N)-doped carbon catalysts in oxygen reduction reaction (ORR) is very important but still facing with challenges. Herein, we proposed a “solvent effect” strategy to prepare a high active N-doped carbon catalyst with trace iron (N-C-Fe-ethanol, 0.10 at.% Fe) via pyrolysis of polyaniline (PANI)-iron (Fe) coordination polymer washed with ethanol. Electrochemical results show that N-C-Fe-ethanol catalyst exhibits a remarkable 109 mV positive shift of half-wave potential compared with that of catalyst unwashed PANI-Fe coordination polymer, and its limiting current density (3.61 mA-cm -2 ) is closer to that of Pt/C catalyst in acid media. It was demonstrated that the surface structure of PANI-Fe coordination polymer could be tuned via removing some nitrogen-containing groups such as –N + = groups and other small molecules on its surface, which helped to generate a high ratio of graphitic N in the pyrolysis process. This work develops a new path for improving the ORR activity of N-doped carbon catalysts.