Microbial fuel cell with a polypyrrole/poly(methylene blue) composite electrode

• Published in: Reports in electrochemistry 2012-01, Vol.2, p.3
• Main Authors: Godwin, Jonathan M, Evitts, Richard W, Kennell, Glyn F
• Format: Article
• Language: English
• Subjects: Electrodes; Equipment and supplies; Fuel cells; Methylene blue; Properties; Pyrrole
• ISSN: 2230-4096; 2230-4096
• DOI: 10.2147/RIE.S33526

Different configurations of anodic and cathodic half-cells were incorporated into a microbial fuel cell to determine the effectiveness of a composite electrode. This novel composite electrode consisted of poly(methylene blue) and polypyrrole electrodeposited onto a stainless steel electrode. The novel electrode/immobilized mediator was incorporated into a microbial cathodic half-cell that relied on the microalgae Chlorella vulgaris for photosynthesis, and was a net reducer of carbon dioxide. Similar microbial cathodic half-cells were also examined using electrodes fabricated from graphite and graphite deposited with methylene blue. Results from using these three different electrodes in the microbial cathodic half-cell were examined and compared with the results from others. The electrode using the novel immobilized mediator demonstrated the highest short circuit current density of 65 mA/[m.sup.2] when compared with other C. vulgaris systems. Different anodic half-cells were also incorporated into the microbial fuel cell and tested. Anodic half-cells tested included a microbial half-cell containing Saccharomyces cerevisiae and one containing no microbial material and based on purely chemical constituents. In the case of the microbial anodic half-cell, different electrodes, including the novel immobilized mediator/electrode, were tested. It was found that the anodic half-cell performed better with a soluble mediator than an immobilized mediator/electrode. In the case of a fuel cell where both the anodic and cathodic half-cells are microbial, our results demonstrate better performance than previous systems by using a soluble mediator in the anodic half-cell with an immobilized mediator in the cathodic half-cell. Keywords: microbial fuel cell, biocathode, immobilized mediator, stainless steel electrode