An MFC capable of regenerating the cathodic electron acceptor under sunlight

Abstract

A renewable MFC (microbial fuel cell) cathode was used in this study because the iodide ion could react with oxygen to generate triiodide under natural sunlight. The feasibility of the regeneration of triiodide ion under natural sunlight and the effect of the regenerated triiodide ion concentration on the MFC performance were studied. The results showed that the power density of the MFC using triiodide ion as cathodic electron acceptor was significantly higher than that of using ferricyanate, and that the iodide ion can be oxidized to triiodide ion by oxygen in air at the expense of natural sunlight. In addition, it was obvious from the experimental results that the MFC performance was improved with the increase of the triiodide concentration, indicating that the concentration of triiodide ion had a critical effect on the MFC performance. The linear sweep voltammetry (LSV) curves for the electro-reduction of triiodide ion on the carbon paper were obtained and the results suggested that the diffusion process of triiodide ions to cathode was the control factor for the MFC performance.