Efficient Co-MoS2 electrocatalyst for cathodic degradation of halogenated disinfection by-products in water sample

Abstract

The development of non-noble metal electrocatalysts that are efficient and low-cost are being sought as alternatives to noble metals for electrochemical degradation of organic halides. In this study, Co-MoS2, a non-noble metal electrocatalyst, was synthesized and deposited on graphite felt (GF) via the hydrothermal approach. The functionalized graphite felt was used as a cathode electrode for reductive degradation of halogenated disinfection products from water samples. Five halogenated disinfection byproducts (DBPs), CHBr2Cl, C3H5Br2Cl, CHBr3, CHCl3, and CCl4 were selected as model compounds, and electro-reductive degradation by the electrode was evaluated. The batch experiments performed with an undivided electrolytic cell revealed that the Co-MoS2-GF electrode exhibited superior electrocatalytic degradation towards the DBPs compounds compared to other reported electrodes in literature. Co-MoS2-GF electrode displayed a current efficiency of ̴ 13% and degradation efficiency of more than 90% for each of the DBPs after 60 min of electrolysis. The enhanced catalytic activity of the Co-MoS2 was ascribed to the synergistic role of CoS /MoS2 towards the accelerated Volmer step of hydrogen evolution reaction (HER), which aided the production of surface-bound atomic hydrogen *H. Cyclic voltammetry and scavenging experiments clarify the formation of *H during Co-MoS2-GF catalyzed water reduction and show its contribution to DBPs degradation. The prepared Co-MoS2-GF electrode also displayed substantial stability and reusability potential even after ten cycles of recurring operation.