Strain-Enabled Band Structure Engineering in Layered PtSe₂ for Water Electrolysis under Ultralow Overpotential.

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Hydrogen evolution reaction (HER) is crucial for water electrolysis.
• Developing efficient and cost-effective catalysts is essential for advancing HER technology.
• Platinum-based materials are effective HER catalysts but are expensive.

Purpose of the Study:

• To develop a simple design methodology for layered PtSe₂ catalysts.
• To enhance the catalytic activity of PtSe₂ for HER through strain engineering.
• To investigate the fundamental mechanisms behind strain-induced HER enhancement.

Main Methods:

• Mechanically exfoliating PtSe₂ flakes.
• Transferring PtSe₂ flakes onto gold thin films on prestrained thermoplastic substrates.
• Inducing tunable uniaxial strain via surface wrinkles upon relieving prestrain.
• Utilizing Density Functional Theory (DFT) calculations for mechanistic insights.

Main Results:

• Achieved layered PtSe₂ catalysts operating under ultralow overpotentials.
• Strain engineering modulated the band structure of PtSe₂, overlapping valence band maximum and conduction band minimum.
• Optimized tensile strain in PtSe₂ significantly amplified HER performance, exceeding pure platinum.
• Demonstrated significantly reduced charge transfer resistance in strain-engineered PtSe₂.

Conclusions:

• Strain engineering is an effective strategy to enhance PtSe₂ catalytic activity for HER.
• The developed methodology provides a pathway for designing advanced catalysts for water electrolysis.
• DFT calculations confirm the correlation between strain-induced band structure changes and improved HER activity at edge sites.