Low-cost adsorbent derived and in situ nitrogen/iron co-doped carbon as efficient oxygen reduction catalyst in microbial fuel cells

A novel low-cost adsorbent derived and in situ nitrogen/iron co-doped carbon (N/Fe-C) with three-dimensional porous structure is employed as efficient oxygen reduction catalyst in microbial fuel cells (MFCs). The electrochemical active area is significantly improved to 617.19 m(2) g(-1) in N/Fe-C by Fedoping. And N/Fe-C (4.21 at.% N, 0.11 at.% Fe) exhibits excellent electrocatalytic activity with the oxygen reduction potential of -0.07 V (vs. Ag/AgCl) which is comparable to commercial Pt/C. In MFCs tests, the maximum power density and output voltage with N/Fe-C are enhanced to 745mW m(-2) and 562 mV (external resistance 1 k Omega), which are 11% and 0.72% higher than Pt/C (0.5 mg Pt cm(-2)), respectively. Besides, the long-term stability of N/Fe-C retains better for more than one week. Moreover, the charge transfer resistance (Rct) values are recorded by the impedance measurements, and the low Rct of N/Fe-C is also result in better catalytic activity. (C) 2016 Elsevier Ltd. All rights reserved.