Three dimensional (3D) nanostructured assembly of MoS2-WS2/Graphene as high performance electrocatalysts

• Published in: International journal of hydrogen energy 2020-03, Vol.45 (17), p.10475-10485
• Main Authors: Lonkar, Sunil P., Pillai, Vishnu V., Alhassan, Saeed M.
• Format: Article
• Language: English
• Subjects: 3D assembly; Electrocatalysts; Graphene; Hydrogen evolution reaction; MoS2-WS2; Nanostructured hybrids
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2019.03.195

A promising electrocatalyst material composed of 2D layered MoS2-WS2 heterostructure hierarchically assembled into a 3D highly interconnected macroporous network of graphene was facilely fabricated. This in-situ synthesis method involves hydrothermal reaction followed by moderate thermal annealing which guarantees the uniform distribution of the MoS2-WS2 heterojunctions within graphene matrix. The presence of 3D conductive and porous graphene network and the combined merits of MoS2 and WS2 endow the resulting 3D MoS2-WS2/graphene nanohybrids with unique conductivity pathways and channels for electrons and with outstanding electrocatalytic performance towards enhanced hydrogen evolution reaction (HER). This 3D nanohybrid delivered the small overpotential of 110 mV, and the small Tafel slope of 41 mV per dec, demonstrating high HER activity. Furthermore, the resulting nanohybrids exhibit excellent stability as very trivial drop in the current density was noticed even after 2000 cycles. The superior electrocatalytic performance of 3D MoS2-WS2/graphene over other non-precious metal electrocatalysts is accredited to the robust synergism of 2D MoS2-WS2 with 3D graphene that offer ample active sites and improved conductivity for HER. The proposed approach can be further extended to modify other layered transition metal dichalcogenides with hierarchical 3D porous structure as a competent electrocatalysts for HER. [Display omitted] •Facially fabricated a 3D nanostructured assembly of MoS2-WS2/graphene by hydrothermal method.•In-situ synthesis ensure the uniform distribution of MoS2-WS2 within graphene and high active sites density.•The heterostructured nanohybrid exhibit remarkable electrocatalytic performance in HER reaction.•The nanohybrid with optimized graphene shows better electrocatalytic activity.