Hetero-architectured core–shell NiMoO4@Ni9S8/MoS2 nanorods enabling high-performance supercapacitors

Abstract

An effective technique for improving electrochemical efficiency is to rationally design hierarchical nanostructures that completely optimize the advantages of single components and establish an interfacial effect between structures. In this study, core–shell NiMoO4@Ni9S8/MoS2 hetero-structured nanorods are prepared via a facile hydrothermal process followed by a direct sulfurization. The resulting hierarchical architecture with outer Ni9S8/MoS2 nanoflakes shell on the inner NiMoO4 core offers plentiful active sites and ample charge transfer pathways in continuous heterointerfaces. Ascribing to the porous core–shell configuration and synergistic effect of bimetal sulfides, the obtained NiMoO4@Ni9S8/MoS2 as electrode material presents an unsurpassed specific capacity of 373.4 F g−1 at 10 A g−1 and remarkable cycling performance in the 6 M KOH electrolyte. This work delivers a rational method for designing highly efficient electrodes for supercapacitors, enlightening the road of exploring low-cost materials in the energy storage domain. Graphical Abstract

A cycle-durable hollow nanoneedle structure with a nanosheet as a conductive substrate CoS1.097/Ni9S8@RGO to enhance supercapacitor performance

“…The doublets were assigned to Ni 2+ (855.4 and 872.9 eV) and Ni 3+ (856.4 and 874.4 eV), respectively. 31 The Co 2p 3/2 peaks at 781.5 and 776.0 eV were characteristics of Co 2+ and Co 3+ species, and the Co 2p 1/2 peaks observed at 796.7 and 790.2 eV were characteristic of Co 2+ and Co 3+ species (Fig. 3f).…”

Mn-Doped Crystalline Ni3S2/Amorphous MoS2 Core–Shell Nanorods as Bifunctional Electrocatalysts for Highly-Efficient Overall Water Splitting

“…Figure c demonstrates that the high-resolution XPS spectrum of S 2p of Mn–Ni 3 S 2 @MoS 2 can be deconvoluted into five peaks at 161.58, 163.58, 162.38, 164.95, and 168.95 eV, among which 161.58 and 163.58 eV are possibly related to S 2p 3/2 and S 2p 1/2 in the Mo–S bond, respectively. The peaks at 162.38 and 164.95 eV are ascribed to S 2p 3/2 and S 2p 1/2 in the Ni–S bonds. − The strong peak at 168.95 eV is attributed to SO 4 2– , owing to the surface sulfur atoms oxidized by molybdate salts . The weak S–O bonds of Mn–Ni 3 S 2 and Ni 3 S 2 at 168.03 and 167.94 eV might be attributed to oxidation during the preparation process .…”

Interface engineering of a Ni9S8/MoS2/Ni3S2 heterostructure to boost biomass upgrading coupled with the hydrogen evolution reaction at large current densities

“…1(c)–(e)), it can be seen that, after the sulfurization of Ni–Mo–O-2 by 3 mmol thiourea, flower-like microspheres are attached to the nanosheet surface due to Kirkendall diffusion. 30,43 We also compared the influence of different amounts of thiourea on the formation of these heterojunction materials; from Fig. S3 (ESI†), it could be found that, when 1 mmol thiourea was added, the resulting products still retain their original lamellar nanosheets except that the surface became rougher and partial aggregation occurred.…”

“…To date, it has been demonstrated that electrocatalysts with two dimension (2D)-nanosheet morphology have abundant active sites; in addition, electrocatalysts with heterogeneous interfaces possess the appropriate binding energy for the intermediate species and enhance charge transfer by the formation of the strong interface electronic coupling interaction induced by built-in electric field. 27–41 Recently, different bimetallic precursors have been used to construct metal sulfide heterostructures via the sulfurization reaction such as metal oxides/hydroxides or metal organic frameworks (MOFs). For example, Yu et al prepared NiS 2 and MoS 2 2D nanosheets by controlled surface sulfidation of bimetallic NiMoO 4 for high-current-density electrocatalytic water splitting.…”