Application of a cobalt porphyrin as catalyst in microbial fuel cells

A microbial fuel cell (MFC) is a renewable energy device in which microorganisms consume organic matter to generate electricity. These devices have potential utility in wastewater treatment facilities to dually clean the water and generate part of the electricity needed for water treatment. The last decade has seen tremendous advancement in MFC technology, but many challenges remain, particularly with improving performance and efficiency of cathodes. The cathode reduces oxygen to water and traditionally has utilized precious metals as the primary catalytic compound. In these studies, the precious metal in the cathode has been replaced with alternative catalysts. Metalloorphyrin may serve as an effective, low cost oxygen reducing catalyst capable of operating in air-cathode MFCs. Here, a cobalt(II)-porphyrin complex compounded with carbon black support (porphyrin/C) was fabricated into an air-cathode for the MFC and its performance was tested. Various cobalt porphyrin loading densities were investigated in order to determine the optimal catalyst loading as determined by power production in MFCs. The cathodes were further examined by polarization curves and voltammetry tests to exam electrochemical performance of the cathodes. As a result, cobalt porphyrin cathode obtained power output was comparable to a power output observed from a MFC with Pt-based cathode, with a decrease in the cost of the cathode compared to platinum