Electrostatically Coupled Nanostructured Co(OH)₂–MoS₂ Heterostructures for Enhanced Alkaline Hydrogen Evolution

Abstract

The development of earth-abundant and highly efficient electrocatalysts for hydrogen evolution reaction (HER) in alkaline media is essential for practical alkaline water electrolysis. The possibility of tuning the electrocatalytic activity of alkaline HER electrocatalysts through various approaches, such as interfacial engineering or doping, has been recently explored. In this work, electrochemically exfoliated Co­(OH)2 and chemically derived 1T-MoS2 nanostructures are electrostatically coupled to form a synergistic nanostructured two-dimensional heterostructure, which is shown to remarkably improve the HER activity in an alkaline medium. The Co­(OH)2/1T-MoS2 heterostructure with an optimal 1:5 ratio (Co1Mo5) showed a low overpotential of 151 mV at a current density of 10 mA cm–2 and a Tafel slope of 94 mV dec–1 in alkaline media. The shift in the overpotential achieved for the heterostructure (>250 mV) compared to the individual MoS2 component is remarkably high, as per the earlier reports.

Charge Redistribution of Co9S8/MoS2 Heterojunction Microsphere Enhances Electrocatalytic Hydrogen Evolution

“…This indicates that there is a synergistic effect between the Co 9 S 8 and the MoS 2 which facilitates the hydrogen evolution reaction. In addition, the activity of the Co 9 S 8 /MoS 2 catalysts fabricated in this work is better than the overpotential values of most relevant heterojunction materials reported in the literature ( Table 1 ) [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. The Tafel slope of the Co 9 S 8 /MoS 2 is 92.6 mV dec −1 , which is lower than that of the Co 9 S 8 at 106.1 mV dec −1 or the MoS 2 at 127.8 mV dec −1 ( Figure 7 b).…”

Interface Coupling of Cobalt Hydroxide/Molybdenum Disulfide Heterostructured Nanosheet Arrays for Highly Efficient Hydrazine-Assisted Hydrogen Generation

“…In addition, the assembled Co­(OH) 2 /MoS 2 /CC-based electrolyzer exhibits low potentials of 142, 197, and 271 mV to reach 10, 50, and 100 mA cm –2 for OHzS, respectively, suggesting the promising potential application in energy-saving hydrogen generation. Compared to previously reported work, − our study offers a simple method for designing electrodes with high activity, low cost, and robust stability based on Co­(OH) 2 and MoS 2 materials that are easy to overlook, realizing the synergistically improved bifunctional activity, which has important instructive significance for energy-saving hydrogen evolution.…”

“…Recently, layered metal hydroxide with no charge balancing anions in the interlayer is proven to be a feasible way to regulate the electrical behavior of MoS 2 by redistributing the density of states and Fermi energy level. − A strong electrostatic coupling between MoS 2 and metal hydroxide endows high catalytic activity by realizing the faster electrolytic process of water dissociation with a lower energy barrier . Inspired by this advantage, we put forward a facile strategy to develop interface-coupled Co­(OH) 2 /MoS 2 nanosheet arrays, presenting a highly active electrode material for energy-saving hydrogen production by using a hydrazine oxidation reaction to assist water splitting.…”

Recent strategies for activating the basal planes of transition metal dichalcogenides towards hydrogen production

“…14,166,167 Here, we would discuss the synergistic effect 168,169 and the interfacial charge transfer [170][171][172] originating from heterostructures. So far, the synergistic effects have also been frequently observed in hydroxide/TMDC, [173][174][175][176] TMDC/ TMDC, [177][178][179][180] oxide/TMDC, [181][182][183] and others. [184][185][186][187] As discussed in Section 2, the high adsorption energy of H 2 O hinders the generation of H ad intermediates, leading to sluggish kinetics in alkaline solution.…”