Polysulfide-Induced Synthesis of Coral-Like MoS₂/NiS₂ Nanostructures for Overall Water Splitting

Abstract

The development of multifunctional electrocatalysts with rich resources, excellent performance, and stability is necessary for water splitting to achieve sustainable hydrogen and oxygen production. Herein, we report the preparation of a bifunctional coral-like nanostructured electrocatalyst (p-MoS2/NiS2) by in situ vulcanization of polymeric sulfur with a MoO3/Ni as the precursor. It is exciting that the whole preparation process of the electrocatalyst can be completed in a few hours. The as-fabricated multimetallic sulfide not only exhibits well-defined heterointerfaces and the defect-rich two-dimensional (2D) nanoconfiguration with high conductivity to overcome the poor hydrogen evolution reaction (HER) activity, but also promotes the formation of the 1T phase. The obtained p-MoS2/NiS2 nanostructures exhibit low overpotentials of −115 mV at −10 mA cm–2 and 337 mV at 100 mA cm–2 toward the HER and oxygen evolution reaction (OER), respectively, which surpass most of the previously reported bimetallic sulfide-based electrocatalysts. Benefiting from the stability of the hierarchical heterostructure and the coupling effect between the inner layer of NiS2 and outer layers of MoS2, the p-MoS2/NiS2 catalyst is endowed with high activity for water splitting. It can be used as a bifunctional electrocatalyst for water splitting with a cell voltage of 1.51 V at a current density of 10 mA cm–2. Overall, this work proposes a simple in situ vulcanization method to synthesize MoS2, which expands the interlayer spacing and realizes the coexistence of a metastable structure and metal doping.

Constructing Stable MoOx-NiSx Film via Electrodeposition and Hydrothermal Method for Water Splitting

“…9H5E-CF 9H5E-CC showed high stability with negligible voltage change. Additionally, compared with the reported bifunctional catalysts for HER, OER, and overall water splitting in alkaline electrolytes, a competitive overpotential of 142 mV (η 10 ) for HER, 294 mV (η 50 ) for OER, and 1.88 V (at 50 mA cm −2 ) for overall water splitting were achieved for the MoO 3 -NiS x catalyst, as shown in Table S4 [39][40][41][42][43][44][45][46][47][48][49][50][51].…”

“…The following supporting information can be downloaded at: https:// www.mdpi.com/article/10.3390/catal13111426/s1, Figure S1 S1: Listing of the experimental parameters for fabricating the samples; Table S2: R s and R ct values of 9H5E-CC, 9H-CC, and 9H15-CC; Table S3: R s and R ct values of 9H5E-CF, 9H-CF, and 9H15-CF; Table S4: Comparison of the water splitting performance of the catalyst in this study with that of other reported bifunctional catalysts in 1 M KOH. References [39][40][41][42][43][44][45][46][47][48][49][50][51] are cited in the Supplementary Materials.…”

CoFe-Layered Double Hydroxide Needles on MoS2/Ni3S2 Nanoarrays for Applications as Catalysts for Hydrogen Evolution and Oxidation of Organic Chemicals

“…37,38 Constructing a heterojunction between MoS 2 and other catalysts is a highly effective strategy to enhance the electrocatalytic performance of OWS. 39,40 The formation of a heterojunction induces band bending at the interface due to differences in Fermi energy levels, resulting in electron redistribution and the creation of an intrinsic electric field. This contributes to the acceleration of electron migration between interfaces and the formation of new active sites.…”