Large-scale Two-dimensional MoS_x Catalyst Prepared under Mild Conditions for Enhancing Electrocatalytic Hydrogen...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Molybdenum disulfide (MoS₂) is a promising, earth-abundant alternative to expensive noble-metal catalysts for electrocatalytic hydrogen reactions.
• Large-scale production of few-layer MoS₂ with enhanced electrocatalytic activity remains a significant challenge.
• Developing efficient and scalable synthesis methods is crucial for practical applications.

Purpose of the Study:

• To develop a simple, environmentally friendly, and scalable method for preparing defect-rich MoS_x nanosheets.
• To investigate the effect of sulfur vacancies on the electrocatalytic hydrogen evolution reaction (HER) activity.
• To demonstrate the potential of this method for producing other 2D materials.

Main Methods:

• A two-step synthesis involving intercalation reaction followed by electrochemical reduction.
• Controlled desulfurization voltage to tune the sulfur-molybdenum atomic ratio (from 2:1 to 1.4:1).
• Characterization of the synthesized MoS_x and evaluation of its HER performance.

Main Results:

• Successfully prepared defect-rich desulfurized MoS_x (D-MoS_x) nanosheets with tunable sulfur vacancies.
• D-MoS_x exhibited enhanced HER catalytic activity compared to pristine MoS₂ (P-MoS₂).
• Current density of D-MoS_x (desulfurized at -1.0 V) was 169% of P-MoS₂ at -0.3 V vs RHE, with a reduced Tafel slope of 136 mV dec^-1.

Conclusions:

• The developed method enables mass preparation of defect-rich D-MoS_x with improved HER performance.
• Sulfur vacancies play a key role in enhancing the electrocatalytic activity of MoS₂.
• The synthesis strategy is versatile and applicable for large-scale production of other 2D materials.