Two-Dimensional Metal Dichalcogenides and Oxides for Hydrogen Evolution: A Computational Screening Approach

Area of Science:

• Materials Science
• Catalysis
• Computational Chemistry

Background:

• The hydrogen evolution reaction (HER) is crucial for clean energy technologies.
• Discovering efficient and cost-effective electrocatalysts for HER is a major research focus.
• Two-dimensional (2D) materials offer unique properties for catalysis, but their potential for HER is not fully explored.

Purpose of the Study:

• To computationally screen 2D metal dichalcogenides and oxides for their potential as HER electrocatalysts.
• To utilize hydrogen binding energy as a descriptor for predicting catalytic activity.
• To explore the influence of different structural phases (2H and 1T) on HER activity.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Hydrogen binding energy was calculated as a descriptor for HER activity.
• Electronic structure analysis, specifically shifts in chalcogenide p-levels, was performed to rationalize activity differences between phases.
• Formation energies of different phases were compared.

Main Results:

• The study identified specific 2D metal dichalcogenides and oxides with potential for HER.
• A structure-dependent activity was observed, with different phases (2H vs. 1T) showing varying hydrogen binding strengths for different materials (e.g., Ti, Zr, Hf vs. Cr, Mo, W).
• While typically only one phase is active, the close formation energies between phases suggest the possibility of stabilizing the active phase.

Conclusions:

• Many new 2D materials beyond currently known ones show promise for HER.
• Understanding the interplay between crystal structure and electronic properties is key to designing effective HER electrocatalysts.
• This work provides a computational framework for discovering novel 2D HER materials.