In-situ constructed metallic Mo decorated MoS2 nanosheets on carbon cloth as excellent anode for efficient current generation and Cr(Ⅵ) removal

Abstract

The anode, as the host site of exoelectrogens, is considered to be a crucial factor in determining the current generation of microbial fuel cells (MFCs), which is constrained by sluggish extracellular electron transfer (EET) on the exoelectrogens/anode interface. To facilitate the EET efficacy, herein, MoS2 nanosheets decorated with metallic Mo are rational designed to grow vertically and uniformly on carbon cloth (CC). This not only avoids the use of bonding agents, but also compensates for the inherent defects of MoS2 semiconductors, displaying an extremely low charge-transfer impedance of 4.6 Ω and a remarkable specific area capacitance of 435.97 F/m2. As expected, MFC equipped with Mo/MoS2-CC anode was faster started up for 1.35 d, achieving a superior power density of 3.25 W/m2 (8.15 d, 1.96 W/m2, CC), which is attributed to the continuous modification of CC surface properties via Mo/MoS2 nanosheets, boosting the electroactive bacterial attachment and EET process. Most importantly, the enhanced current intensity of Mo/MoS2-CC anode provides more robust and sustained electron for the cathodic Cr(Ⅵ) reduction, acquiring about 100% removal of Cr(Ⅵ) at the initial Cr(Ⅵ) concentration of 40 mg/L (75.5%, CC). This work exhibits a new idea for high performance anode design and long-term efficient Cr(Ⅵ) removal.