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

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 onedimensional TiO2/Fe2O3 photoanode and conventional bioanode to overcome the constraints of using traditional anodes. The novel MFC has the maximum power density of 638.3 mWrn(-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.