Facile Spin-Coated MoS₂ Thin Films from a Single-Source Precursor for HER Activity

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The hydrogen evolution reaction (HER) is crucial for clean energy production, requiring efficient catalysts.
• Molybdenum disulfide (MoS₂) is a promising, earth-abundant alternative to platinum for HER catalysis.
• Engineering MoS₂ thin films can create active sites for enhanced HER performance.

Purpose of the Study:

• To synthesize large-area MoS₂ thin films for HER applications.
• To investigate the effect of film thickness on HER activity.
• To understand the role of sulfur vacancies in HER performance.

Main Methods:

• Preparation of MoS₂ thin films via spin coating of MoCl₅ precursor followed by sulfurization annealing.
• Characterization using Raman spectroscopy, X-ray diffraction (XRD), UV-vis, and X-ray photoelectron spectroscopy (XPS).
• Electrochemical testing to evaluate HER activity and Tafel slope.

Main Results:

• Successfully synthesized MoS₂ thin films with controllable thickness.
• Demonstrated HER activity in synthesized MoS₂ films, with thinner films (10 nm) showing better performance (290 mV overpotential) than thicker films (50 nm at 369 mV).
• XPS analysis revealed sulfur vacancies, which positively correlate with enhanced HER activity. A Tafel slope of 80 mV/decade was achieved.

Conclusions:

• MoS₂ thin films are effective catalysts for the hydrogen evolution reaction.
• Film thickness and sulfur vacancy concentration are critical factors influencing HER performance.
• The synthesized MoS₂ films offer a cost-effective and efficient alternative to platinum-based catalysts for HER.