Evaluation of Order Mesoporous Carbon As Anode Catalyst for Microbial Fuel Cells

Abstract

Ordered Mesoporous Carbon (OMC) synthesized via self-assembly in aqueous phase, was evaluated as anode catalyst for Microbial Fuel Cells (MFCs) applications. Prior to electrochemical characterization, OMC was functionalized with methanol. The catalytic activity of non-funtionalized and functionalized OMC was compared to that of commercial Vulcan XC-72 and Graphite flakes (non-functionalized and functionalzied with methanol as well). Gas diffusion electrodes containig a catalytic layer of the catalysts were prepared by the painting technique. The Bacilus Subtilis microorganism was used to grow a biofilm over the carbonaceous catalysts and promote the bioelectrochemical reactions, while residual water directly from a pharmaceutical company (pH=9.6) was the electrolyte. Half-cell characterization was carried out in a three-electrode cell, at which Functionalized OMC showed the highest current density generated from the bioelectrochemical reactions occurring from the residual water. A dual chamber MFC was implemented, where the anode chamber contained residual water in N2 atmosphere, while the electrolyte at the cathode was O2-saturated KOH (pH=9.6). The anode catalysts were: Functionalized OMC, non-Funtionalized OMC, Functionalized Vulcan and commercial 20 % Pt/C, all containing a biofilm by Bacilus Subtilis. The cathode catalyst was commercial 20 % Pt/C. The characterization of the the MFC showed a significantly higher catalytic activity of Functionalized OMC + Bacilus Subtilis for the reactions. It delivered an Open Circuit Voltage (OCV) of 0.58 V and a maximum current density (jcell) of 854 mA m-2. These values were higher than those of Pt/C (2.6 and 4.7 higher OCV and jcell, respectively). The results showed that methanol-Functionalized OMC is a metal-free catalyst with high performance for MFCs.