Three-Dimensional Hierarchical Frameworks Based on MoS₂ Nanosheets Self-Assembled on Graphene Oxide for Efficient Electrocatalytic Hydrogen Evolution

Abstract

Advanced materials for electrocatalytic water splitting are central to renewable energy research. In this work, three-dimensional (3D) hierarchical frameworks based on the self-assembly of MoS2 nanosheets on graphene oxide were produced via a simple one-step hydrothermal process. The structures of the resulting 3D frameworks were characterized by using a variety of microscopic and spectroscopic tools, including scanning and transmission electron microscopies, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman scattering. Importantly, the three-dimensional MoS2/graphene frameworks might be used directly as working electrodes which exhibited apparent and stable electrocatalytic activity in hydrogen evolution reaction (HER), as manifested by a large cathodic current density with a small overpotential of -107 mV (-121 mV when loaded on a glassy-carbon electrode) and a Tafel slope of 86.3 mV/dec (46.3 mV/dec when loaded on a glassy-carbon electrode). The remarkable performance might be ascribed to the good mechanical strength and high electrical conductivity of the 3D frameworks for fast charge transport and collection, where graphene oxide provided abundant nucleation sites for MoS2 deposition and oxygen incorporation led to the formation of defect-rich MoS2 nanosheets with active sites for HER.

Solvent-Assisted Oxygen Incorporation of Vertically Aligned MoS2 Ultrathin Nanosheets Decorated on Reduced Graphene Oxide for Improved Electrocatalytic Hydrogen Evolution

“…18,43 The enlargement of the interlayer distance of O-MoS 2 sheets is further confirmed by the XRD pattern (002 diffraction peak shifts to 9.1°, Figure 2a) when compared to bulk MoS 2 (2H-MoS 2 , JCPDS 37-1492) with the 002 diffraction peak located at 14.2°. 6,14,35,44 The broad peak at approximating to 23.9°suggests the formation of stacked rGO nanosheets and the successful reduction from GO to rGO after …”

Facile synthesis of MoS2/reduced graphene oxide composites for efficient removal of Cr(vi) from aqueous solutions

“…MoS 2 embedded in graphene sheets through a simple hydrothermal method can be helpful for the reduction of overlapping and coalescing of graphene layers, enlarging the specic surface area and increasing the adsorption capacity of the material. The combination of graphene and MoS 2 has already shown to have an excellent electrochemical performance, 12 and it may also produce new properties through their interactions. In this study, we synthesized MoS 2 /rGO by a simple solvothermal process, which was used for removing Cr(VI) from aqueous solutions for the rst time.…”

3D MoS2-Graphene Composite as Catalyst for Enhanced Efficient Hydrogen Evolution

“…The as-synthesized MoS 2 -RGO-3 catalysts show negligible loss even after continuous 2000 cycles and maintain the current density at 97.3% compared with its initial value (Figure 6 B), indicating the superior long-time stability of the MoS 2 -RGO-3 composite in acid media. This could be attributed to the 3D network structures [34] and intimate contact [35,36] between the MoS 2 nanosheets and RGO hydrogel, decreasing the volume change during the long time test in acid media [37].…”