Phase-dependent growth of Pt on MoS₂ for highly efficient H₂ evolution.

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Two-dimensional transition-metal dichalcogenides (TMDs) are crucial for nanomaterial synthesis and catalysis.
• The crystal phase of TMDs significantly impacts their properties and the growth of supported materials.
• Understanding TMD crystal phase effects is vital for developing advanced catalysts, particularly for the hydrogen evolution reaction.

Purpose of the Study:

• To investigate how different crystal phases of molybdenum disulfide (MoS₂) nanosheets affect the growth and dispersion of platinum (Pt) nanoparticles.
• To evaluate the electrocatalytic performance of Pt nanoparticles supported on phase-pure MoS₂ for the hydrogen evolution reaction.

Main Methods:

• Synthesis of phase-pure 2H and 1T' molybdenum disulfide (MoS₂) nanosheets.
• Deposition of platinum (Pt) nanoparticles and single atoms onto MoS₂ templates.
• Characterization of material structure and composition.
• Electrochemical evaluation of hydrogen evolution reaction (HER) activity and stability using density functional theory (DFT) calculations and experimental measurements.

Main Results:

• 2H-phase MoS₂ templates facilitate epitaxial growth of Pt nanoparticles.
• 1T'-phase MoS₂ supports highly dispersed single-atom platinum (s-Pt) with up to 10 wt% loading.
• s-Pt/1T'-MoS₂ exhibits excellent electrocatalytic activity for HER in acidic media, with a mass activity of 85 ± 23 A/mg and mass-normalized exchange current density of 127 A/mg.
• DFT calculations suggest optimal hydrogen adsorption on Pt atoms located atop Mo atoms in the s-Pt/1T'-MoS₂ system.

Conclusions:

• The crystal phase of MoS₂ is a critical determinant for controlling Pt nanostructure formation and catalytic performance.
• Single-atom Pt supported on 1T'-MoS₂ demonstrates high efficiency and stability for the hydrogen evolution reaction at room temperature.
• 1T'-TMDs show promise as versatile supports for other catalytic applications.