Design of Two-Dimensional, Ultrathin MoS₂ Nanoplates Fabricated Within One-Dimensional Carbon Nanofibers With Thermosensitive Morphology: High-Performance Electrocatalysts For The Hydrogen Evolution Reaction

Two-dimensional MoS₂ nanoplates within carbon nanofibers (CNFs) with monolayer thickness, nanometer-scale dimensions and abundant edges are fabricated. This strategy provides a well-defined pathway for the precise design of MoS₂ nanomaterials, offering control over the evolution of MoS₂ morphology from nanoparticles to nanoplates as well as from mono- to several-layer structures, over a lateral dimension range of 5 to 70 nm. CNFs play an important role in confining the growth of MoS₂ nanoplates, leading to increases in the amount of exposed edge sites while hindering the stacking and aggregation of MoS₂ layers, and accelerating electron transfer. The controlled growth of MoS₂ nanoplates embedded in CNFs is leveraged to demonstrate structure-dependent catalytic activity in the hydrogen evolution reaction (HER). The results suggest that increases in the number of layers and the lateral dimension result in a decrease in HER activity as a general rule. Single-layer MoS₂ nanoplates with abundant edges and a lateral dimension of 7.3 nm demonstrated the lowest hydrogen evolution reaction overpotential of 93 mV (<i>J</i> = 10 mA/cm²), the highest current density of 80.3 mA/cm² at η = 300 mV and the smallest Tafel slope of 42 mV/decade. The ability of MoS₂–CNFs hybrids to act as nonprecious metal catalysts indicates their promise for use in energy-related electrocatalytic applications