MoS2 nanosheets embedded in α-FeOOH as an efficient cathode for enhanced MFC-electro-Fenton performance in wastewater treatment

Abstract

Microbial fuel cell-electro-Fenton system (MEF) has attracted attention due to refractory organic pollutants removal, where H2O2 is in-situ produced without external energy supply. Enhancement of H2O2 production and the activation of H2O2 to ·OH are the keys to improve degradation performance. Development of bifunctional catalytic cathode is a viable strategy. Herein, the α-FeOOH/MoS2 nanocomposites was fabricated by a novel facile hydrothermal method based on molybdenite-exfoliated MoS2 nanosheets suspension, which was used as modified cathode in a MEF system. The obtained α-FeOOH/1 wt%MoS2 cathode exhibited highest power density of 292.38 mW/m2, which was about 3.7 and 1.7 times higher than that of graphite plate and α-FeOOH, respectively. Doping of MoS2 nanosheets significantly enhanced electrocatalytic activity of the cathode and promoted in-situ H2O2 generation. Meanwhile, the exposed reductive Mo4+ on the surface of MoS2 could greatly facilitate the conversion cycle of Fe(III)/Fe(II), leading to the efficient activation of H2O2 into ·OH. The MEF with α-FeOOH/1 wt%MoS2 cathode exhibited excellent degradation and mineralization performance for MB, rhodamine B and tetracycline hydrochloride at optimized reaction condition. Furthermore, the MEF can simultaneously achieve MB oxidation and Cr(VI) reduction, and the corresponding removal ratio can reach up to 91.45% and 100%, respectively. Based on simple preparation method as well as recyclability and excellent catalytic property, the α-FeOOH/MoS2 composite catalyst is considered as a promising MEF cathode for efficient wastewater treatment.