Simultaneous removal of methylene blue and Cr(VI) in a dual-chamber photocatalytic microbial fuel cell with WO3/MoS2/FTO photocathode
Jiye Xin, Shishi Kong, Xiaoliang Zhang, Yujuan Yang, Xuan Wang
Abstract
<h2>Abstract</h2> Carbon felt was used as the anode and WO<sub>3</sub>/MoS<sub>2</sub>/FTO (fluorine-doped tin oxide) was used as the photocathode in a photocatalytic microbial fuel cell (PMFC). The photoelectric performance of the WO<sub>3</sub>/MoS<sub>2</sub>/FTO photocathode and the removal efficiency of methylene blue (MB) and Cr(VI) mixed pollutants were systematically investigated in the cathode chamber. The results showed that after 12 h of light irradiation in the PMFC with WO<sub>3</sub>/MoS<sub>2</sub>/FTO as the photocathode, the removal rates of MB and Cr(VI) were 84.56 and 68.11 %, respectively, which were much higher than those using WO<sub>3</sub>/FTO as a photocathode (55.57 % and 45.26 %, respectively). The corresponding maximum output power was 33.14 mW/m<sup>2</sup>, which was 1.85 times that of the WO<sub>3</sub>/FTO photocathode PMFC. These results can be attributed to the fact that WO<sub>3</sub> is an n-type semiconductor and MoS<sub>2</sub> is a p-type semiconductor. Analysis of trapping experiments showed that the composite of WO<sub>3</sub> and MoS<sub>2</sub> formed a Z-scheme heterojunction, which improved the separation efficiency of the photoelectric carriers and enhanced the pollutant removal efficiency of the photocathode. PMFCs are a new and environment-friendly technology for removing pollutants thereby providing an experimental basis for future engineering applications.