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.