Screening Multi-layered Two-dimensional Cd-chalcogenide Structures as Potential Candidates for Photocatalysis.

Area of Science:

• Materials Science
• Physical Chemistry
• Renewable Energy

Background:

• Photocatalytic water splitting is crucial for sustainable energy generation.
• Two-dimensional (2D) Cd-based semiconductors are promising for photocatalysis.
• The stability and electronic properties of free-standing CdX monolayers require further investigation.

Purpose of the Study:

• To theoretically investigate the stability and electronic properties of few-layer cadmium monochalcogenides (CdX; X=S, Se, Te).
• To assess their potential for photocatalytic water splitting applications.
• To clarify doubts regarding the stability of free-standing CdX monolayers.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Hybrid functionals (HSE06) were used to determine electronic band gaps.
• Band-edge alignment and potential energy surfaces were analyzed for hydrogen evolution.

Main Results:

• Few-layer CdX structures exfoliated from the wurtzite phase are stable, with buckling mitigating acoustic instabilities.
• All stable 2D CdX systems possess electronic band gaps greater than 1.68 eV.
• The chalcogenide site is identified as the most favorable for hydrogen adsorption, with a low energy barrier.

Conclusions:

• Stable 2D CdX materials with suitable electronic band gaps are promising for photocatalytic water splitting.
• The findings address stability concerns and provide insights into hydrogen evolution reaction mechanisms.
• These materials hold potential for efficient and sustainable hydrogen production.