International Journal of Hydrogen Energy, Vol.41, No.43, 19637-19644, 2016
Iron-nitrogen-functionalized carbon as efficient oxygen reduction reaction electrocatalyst in microbial fuel cells
Iron phthalocyanine (FePc) was supported on carbon nanotubes (CNT) and black pearls (BP). The carbon supports were modified by a two-step treatment with nitric acid and ammonia gas to facilitate catalyst dispersion and obtain effective ORR active sites. The treatment allowed introducing oxygen and nitrogen functionalities on the carbon surface while maintaining an extensively developed porous structure, as demonstrated by elemental analysis and BET measurements. Electrochemical activity of the electrocatalysts was assessed by cyclic voltammetry and rotating disk voltammetry experiments. The catalyst obtained by supporting Fe on CNT modified with ammonia gas (Fe-CNT(NH3)) displayed the highest catalytic activity towards ORR at neutral pH as a results of the highest density of pyridinic nitrogen on the sample surface, as indicated by Xray photoelectron spectroscopy (XPS). The applicability of Fe-based electrocatalysts as ORR cathodes of microbial fuel cells (MFCs) was demonstrated by assembling single chamber air-cathodes MFCs and comparing the performance with that a MFC equipped with a reference Pt/C cathode. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.