Boosting electricity generation and Cr(VI) reduction based on a novel silicon solar cell coupled double-anode (photoanode/bioanode) microbial fuel cell.

Abstract Anode electron transfer efficiency is one of the main bottlenecks in determining the performance of microbial fuel cells (MFCs). Here, we report for the first time a novel design of a silicon solar cell equipped MFC with one-dimensional TiO 2 /Fe 2 O 3 photoanode and conventional bioanode to overcome the constraints of using traditional anodes. The novel MFC has the maximum power density of 638.3 mW m−2, which is nearly 7.6 times higher than that of general MFCs (84.2 mW m−2). In addition, the novel MFC achieves 90.9% removal of hexavalent chromium Cr(VI) with concentration of 50 ppm within 13.5 h, and this rate is significantly high at 3.67 g m−3 h−1. Efficient microbial oxidation and photoelectrocatalysis are realized after constructing the SSC with double-anode MFC, thereafter leading to enhanced electron transfer to the external circuit. In addition, the electrons are driven by the built-in electric field in silicon solar cell, in which system barriers are resolved at the same time. Power output and Cr(VI) reduction efficiency are both remarkably enhanced. Such a novel MFC strategy provides new directions for designing new systems that can increase the efficiency of MFCs by utilizing solar energy economically, which further suggest great potential in environmental remediation. Graphical abstract Image 1 Highlights • A SSC coupled double anodes novel MFC constructed for the first time. • Increment of electrons overcame the bottlenecks in traditional MFC. • Decreased transfer barrier realized after utilizing solar energy by SSC. • The maximum power density was 7.6 times higher than that in general MFC. • Such system exhibited high reduction rate (3.67 g m−3 h−1) for Cr(VI) wastewater. [ABSTRACT FROM AUTHOR]