Li-Zhi Huang: Hierarchical MoS2 nanosheets on flexible carbon felt as an efficient flow-through electrode for dechlorination

Li-Zhi Huang,Steen Uttrup Pedersen, Emil Bjerglund Pedersen, Marianne Glasius, Hans Christian B. Hansen and Kim Daasbjerg Interdisciplinary Nanoscience Center (iNANO), Aarhus University MoS2 is well-known as an efficient catalyst for the hydrogen evolution reaction. For the first time, we show that MoS2 is also a promising electrocatalyst for reductive dehalogenation of chlorosubstituted carboxylic acids in water. Molybdenum disulphide nanosheets were grown directly on flexible/soft carbon felt using a facile hydrothermal method. The MoS2 nanosheets loaded carbon felt was used as flow-through electrode for reductive dechlorination of trichloroacetic acid at environmentally relevant conditions resulting in a much more efficient process than using metal electrodes. Atomic hydrogen produced from water reduction at the MoS2 surface can be exploited to accomplish a complete dehalogenation, yet with a dramatic drop in the Faradaic efficiency due to the concomitant dihydrogen evolution. Doping of the MoS2 catalyst with transitional metals resulted in an increase in the Faradaic efficiency as well as the complete dechlorination of trichloroacetic acid to acetic acid. The edge sites of MoS2 is believed to be responsible for the indirect dechlorination involving atomic hydrogen. With the cobalt doped MoS2 catalyst 100% full dechlorination was accomplished at an applied potential of -1.1 V vs. Ag/AgCl using a flow rate of 1 mL min-1. Both catalyst synthesis, electrode preparation, and setup of the electrochemical flow cell are straightforward and readily up-scaled, demonstrating the potential of this methodology in practical applications. Li-Zhi Huang is currently a post-doc at Interdisciplinary Nanoscience Center (iNANO), Aarhus University. He is primarily interested in synthesis and environmental application of 2D materials including MoS2, graphene etc.. Li-Zhi Huang obtain his PhD at University of Copenhagen focus on synthesis of 2D iron oxide materials. He has reported for the first time the synthesis of single sheet iron oxides which are tabular iron oxides with one nanometer thick and with an ordered 2D structure. After finishing his PhD Li-Zhi Huang has been awarded an individual postdoctoral grant (DKK. 2.249.920) from Danish Council for Independent Research&Technology. Thus, he continued his research on the synthesis and environmental application of 2D materials.