Electrocatalysis on Edge-Rich Spiral WS₂ for Hydrogen Evolution

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Transition metal dichalcogenides (TMDs) are promising catalysts for hydrogen generation.
• Defect engineering in TMDs can enhance catalytic activity by increasing active sites.
• The specific role of different defect types, especially line defects like screw dislocations, in TMD catalysis remains underexplored.

Purpose of the Study:

• To investigate the electrocatalytic properties of spiral tungsten disulfide (WS2) domains grown by screw dislocation-driven (SDD) growth for hydrogen evolution.
• To understand the contribution of dislocation lines and edge sites in these spiral structures to catalytic performance.
• To elucidate how SDD line defects influence vertical electrical conduction and overall catalytic activity.

Main Methods:

• Controlled growth of spiral WS2 domains using chemical vapor deposition.
• Fabrication of a micro-electrochemical cell using photo- and electron beam-lithography.
• Electrocatalytic activity measurements using conductive atomic force microscopy (c-AFM) on single spiral WS2 domains, monolayer WS2, and bulk WS2 flakes.

Main Results:

• Spiral WS2 domains exhibit exceptional catalytic properties for the hydrogen evolution reaction.
• The interconnected dislocation lines and abundant edge sites in spiral structures enhance catalytic activity.
• Spiral domains demonstrate improved vertical electrical conduction compared to monolayer and bulk WS2 flakes.

Conclusions:

• Screw dislocation-driven (SDD) line defects in WS2 contribute to a high density of active edge sites.
• These defects enhance hydrogen evolution catalysis without negatively impacting vertical electrical conduction.
• SDD-grown TMDs represent a promising material class for efficient electrocatalytic hydrogen production.