Unveiling the Interfacial Effects for Enhanced Hydrogen Evolution Reaction on MoS₂ /WTe₂ Hybrid Structures

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Monolayer molybdenum disulfide (MoS₂) is a promising electrocatalyst for the hydrogen evolution reaction (HER).
• Enhancing the HER activity of MoS₂ is crucial for efficient hydrogen production.
• Interfacial engineering offers a pathway to improve catalyst performance.

Purpose of the Study:

• To investigate the effect of heterostructured contacts on the HER activity of monolayer MoS₂.
• To elucidate the mechanisms behind the enhanced HER activity in MoS₂-based heterostructures.
• To develop a high-performance MoS₂/WTe₂ hybrid catalyst for HER.

Main Methods:

• Fabrication of MoS₂-WTe₂ heterostructures.
• Electrochemical measurements using microreactors.
• Density functional theory (DFT) calculations.
• Systematic variation of support substrate dielectric constants.

Main Results:

• Heterostructured contacts significantly enhance the HER activity of monolayer MoS₂.
• The primary enhancement mechanism is efficient charge injection through large-area heterojunctions.
• Dielectric screening effects from the substrate play a minor role.
• A fabricated MoS₂/WTe₂ hybrid catalyst achieved an overpotential of -140 mV at 10 mA cm^-2 and a Tafel slope of 40 mV dec^-1 with excellent stability.

Conclusions:

• Large-area heterojunctions are key to enhancing HER activity in MoS₂-based catalysts.
• Interfacial design is critical for optimizing transition metal dichalcogenide (TMD) HER catalysts.
• Electrochemical microreactors provide a robust platform for studying interfacial effects in catalysis.