Power generation using a low-cost sulfated zirconium oxide based cathode in single chamber microbial fuel cells

Innovative and cost effective electrode materials to be used as cathodes in lab-scale MFC prototypes were prepared from mixtures of commercial Platinum on Vulcan (Pt/C) and sulfated zirconia (SZrO2). The catalytic activity of the SZrO2 based catalysts towards the oxygen reduction reaction (ORR) was studied by cyclic voltammetry (CV) and linear sweep voltammetry (LSV), showing comparable electrochemical activity between a mixture with one half of the platinum (Pt) amount and another one containing a higher percentage of Pt. Pt and SZrO2 mixtures showed similar catalytic performance compared to simple Pt/C used as a reference. SZrO2 was used as the cathodic catalyst in a microbial fuel cell (MFC) using phosphate buffer solution and sodium acetate as fuel. The maximum current density and power density recorded are 4220 (mA m−2) and 1079 (mW m−2), respectively. These values are better than those obtained using Pt/C (2539 mA m−2 and 662 mW m−2). Good performances were also reached with a platinum-free cathode based on SZrO2 supported on Vulcan (1420 mA m−2 and 536 mW m−2), demonstrating that these catalysts can be used as substitutes for commercial Pt/C.