Creating Fluorine-Doped MoS₂ Edge Electrodes with Enhanced Hydrogen Evolution Activity.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Edge sites of molybdenum disulfide (MoS₂) exhibit catalytic activity for hydrogen evolution reactions (HER).
• Pristine edge sites have limitations in tuning hydrogen adsorption/desorption and a low density of active atoms.
• Scalable methods are needed to create a high density of active edge sites for efficient HER.

Purpose of the Study:

• To develop a scalable plasma etching technique for creating highly active MoS₂ edge sites.
• To quantitatively characterize the HER activity of engineered MoS₂ edge sites.
• To investigate the effect of fluorine doping on MoS₂ edge site activity.

Main Methods:

• Plasma etching strategy to create MoS₂ edge electrodes.
• Local probe method for quantitative HER activity characterization.
• Fluorine doping of MoS₂ edge sites.

Main Results:

• Plasma etching controllably creates a large number of active sites on MoS₂ edges.
• Fluorine doping enhanced HER activity by fivefold compared to pristine MoS₂ edges.
• The enhanced activity is attributed to more moderate binding energy for hydrogen species.

Conclusions:

• Plasma etching is a scalable technique for designing efficient HER catalysts based on 2D materials.
• Fluorine doping of MoS₂ edge sites offers a novel route for enhancing catalytic performance.
• This work provides insights into doping effects on edge sites at the atomic level.