TiO2 anchored on MoS2 nanosheets based on molybdenite exfoliation as an efficient cathode for enhanced Cr (VI) reduction in microbial fuel cell

Abstract

MoS2 nanosheet-decorated TiO2 nanocomposites were prepared via facile liquid-phase exfoliation of natural molybdenite combined with in situ hydrolysis route. These materials were used as a photocathode for the first time in microbial fuel cell (MFC) to reduce hexavalent chromium (Cr (VI)). Results showed the maximum power density of 1 wt% MoS2/TiO2-based MFC was 3.7 and 1.9 times higher than that of blank graphite and TiO2-based MFC, respectively. This MFC achieved 99.57% removal of Cr (VI) with a concentration of 20 mg L−1 within 8 h under visible light illumination at pH 2 and high degradation rate of 2.49 g m−3 h−1. The introduction of MoS2 nanosheets as a cocatalyst can expand the absorption of visible light, thereby leading to increased electronic participation in Cr (VI) reduction. Moreover, the appropriate amounts of MoS2 nanosheets also contribute to electrons migration and additional active site. The enhanced power output and Cr (VI) reduction efficiency of MFC can be attributed to the synergistic coupling between bioanode and MoS2/TiO2 photocathode. On the basis of its facile and scalable synthetic strategy as well as its stable and outstanding photoelectrocatalytic performance for MFC, this MoS2/TiO2 nanocomposite showed potential in the efficient treatment of wastewater.