Novel Platinum (PT)-Free Cathodes for Microbial Fuel Cells (MFCs) Treating Wastewater

The effects of platinum-free cathodes on power generation and wastewater treatment in microbial fuel cells (MFCs) were investigated in this paper. Single chamber MFC with two anode areas (10 and 40 cm2) and different cathodes (platinum-free and platinum-based) were tested for 6 weeks. The study showed that the power generation of the MFCs was not influenced by the increasing (4 times) in the anode area. The different cathodes investigated gave a significant initial difference (21-27%). While at the beginning the MFCs with Pt-based cathode had higher power generation than the Pt-free cathode MFCs, after few weeks, this difference disappears due to biofilm growth that acts as biocathode, facilitating the cathodic reaction. COD degradation increased slightly with the anodic area, probably due to the increase in biofilm growth on a larger anodic surface. COD degradation was not influenced by the presence/absence of the platinum catalyst on the cathodic electrode. Pt-free cathodes with controlled biofilm growth are promising for low-cost materials, stable power generation and long-term operation of MFCs.