Promotion of anodic electron transfer in a microbial fuel cell combined with a silicon solar cell

• A traditional MFC and a silicon solar cell (SSC) are combined to build a novel MFC–SSC.
• Cell performances are significantly promoted by the SSC in MFC–SSC.
• Anodic microbial oxidation of organic substrate is enhanced in MFC–SSC.
• The SSC is compatible to promote the whole system without influencing anodic microbial reactions.
• Cooperation of anodic microorganisms and SSC improves electron transfer efficiency in the MFC–SSC.

This study focuses on the promotion of electron transfer in microbial fuel cells (MFCs) by equipping a silicon solar cell (SSC) into the circuit. As compared to a sole MFC, a significant improvement of power output is observed in the MFC–SSC, that the maximum power density increases from 7.5 W m−3–19 W m−3 by 2.53 times. A linear relationship between anodic potential and current has been observed when the current is below the limiting point of SSC. We estimate the electron transfer rate can be promoted in a MFC–SSC under the condition that the anodic microbial reactions are unaffected by the incorporation of a SSC. In this way, the anodic electrons are fully pumped and enter into the external circuit. This estimation is thereby demonstrated by the 24-h test, which shows the quantity of the electrons fluent in the circuit of a MFC–SSC is doubled and the microbial oxidation efficiency is improved to 341.6% as compared with a sole MFC.