Manganese cobalt sulfide/molybdenum disulfide nanowire heterojunction as an excellent bifunctional catalyst for electrochemical water splitting

Jagadis Gautam; Debabrata Chanda; Mikiyas Mekete Meshesha; Seok Gwon Jang; Bee Lyong Yang

doi:10.1016/j.jcis.2023.02.029

Manganese cobalt sulfide/molybdenum disulfide nanowire heterojunction as an excellent bifunctional catalyst for electrochemical water splitting

J Colloid Interface Sci. 2023 May 15:638:658-671. doi: 10.1016/j.jcis.2023.02.029. Epub 2023 Feb 9.

Authors

Jagadis Gautam¹, Debabrata Chanda¹, Mikiyas Mekete Meshesha¹, Seok Gwon Jang¹, Bee Lyong Yang²

Affiliations

¹ School of Materials Science and Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi-si, Gyeongsangbuk-do 39177, Republic of Korea; GHS (Green H2 System) Co., Ltd., Gumi-si, Republic of Korea.
² School of Materials Science and Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi-si, Gyeongsangbuk-do 39177, Republic of Korea; GHS (Green H2 System) Co., Ltd., Gumi-si, Republic of Korea. Electronic address: blyang@kumoh.ac.kr.

PMID: 36774879
DOI: 10.1016/j.jcis.2023.02.029

Abstract

Heterointerface engineering enhances catalytic active centers and charge transfer capabilities to increase oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) kinetics. In this study, a novel heterostructure of manganese cobalt sulfide-molybdenum disulfide on nickel foam (MnCo₂S₄-MoS₂/NF) was synthesized via a two-step hydrothermal process. The nanowire-shaped MnCo₂S₄-MoS₂ on NF displayed accelerated charge transfer ability and multiple integrated active sites. When tested in one molar (1 M) potassium hydroxide (KOH) electrolyte, it furnished low overpotentials of 105 and 171 mV for the HER and 220 and 300 mV for the OER at the current densities of 20 and 50 mA cm^-2, respectively. An electrolyzer based on MnCo₂S₄-MoS₂/NF required low operating potentials of 1.41 and 1.49 V to yield the current densities of 10 and 20 mA cm^-2, respectively, surpassing commercial and previously reported catalysts. Density functional theory (DFT) analysis revealed that the MnCo₂S₄-MoS₂ heterostructure possesses the optimal adsorption free energies for the reactants, an extended electroactive surface area, good charge transfer ability, and reasonable density of electronic states close to the Fermi level, all of which contribute to the high activity of catalyst. Thus, heterointerface engineering is a promising strategy for creating efficient catalysts for overall water splitting.

Keywords: Electrocatalyst; Hydrogen evolution reaction; Manganese cobalt sulfide; Molybdenum disulfide; Overall water splitting; Oxygen evolution reaction.