Single-Atom Vacancy Defect to Trigger High-Efficiency Hydrogen Evolution of MoS₂

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Defect engineering in transition metal dichalcogenides (TMDs) is crucial for tuning material properties.
• Sulfur vacancies (S-vacancies) in MoS₂ are known to influence catalytic activity, but their optimal state remains unclear.

Purpose of the Study:

• To determine the optimal concentration and distribution of S-vacancies in MoS₂ for enhanced hydrogen evolution reaction (HER) catalysis.
• To develop a facile method for introducing controlled S-vacancies into MoS₂ nanosheets.

Main Methods:

• High-throughput calculations were used to identify optimal S-vacancy configurations for HER.
• A chemical etching strategy using H₂O₂ was employed to introduce homogeneous S-vacancies into MoS₂ nanosheets.
• Systematic tuning of etching parameters (duration, temperature, concentration) modulated the S-vacancy state.

Main Results:

• The study identified optimized S-vacancy states in MoS₂ for HER through theoretical calculations.
• A facile H₂O₂ etching method successfully introduced homogeneously distributed single S-vacancies.
• Optimal HER performance achieved a Tafel slope of 48 mV dec⁻¹ and an overpotential of 131 mV at 10 mA cm⁻², outperforming agglomerate vacancies.

Conclusions:

• Single S-vacancies in MoS₂ offer superior HER performance compared to agglomerate vacancies due to enhanced electronic structure and electrical transport.
• The developed strategy bridges theoretical design and experimental realization for sophisticated defect engineering in catalysis.
• This work advances the potential of MoS₂-based catalysts for efficient hydrogen production.