Earth-Abundant Tin Sulfide-Based Photocathodes for Solar Hydrogen Production

Area of Science:

• Materials Science
• Photochemistry
• Renewable Energy

Background:

• Tin-based chalcogenides are promising for photovoltaics but show poor photoelectrochemical performance and stability.
• Tin monosulfide (SnS) has potential for solar fuel production but requires optimization.

Purpose of the Study:

• To develop a stable and high-performing tin monosulfide (SnS) photocathode for hydrogen (H₂) production via water splitting.
• To improve the photoelectrochemical performance of SnS using a novel heterojunction strategy.

Main Methods:

• Fabrication of p-type SnS nanoplatelet thin films coated with n-CdS and TiO₂ to form type II heterojunctions.
• Deposition of platinum (Pt) nanoparticles on the heterojunction photocathodes.
• Photoelectrochemical measurements under simulated visible-light illumination.

Main Results:

• The SnS/CdS/TiO₂/Pt photocathodes achieved a photovoltage of 300 mV and photocurrent density of 2.4 mA cm^-2 at 0 V vs RHE.
• Maximum incident photon-to-current efficiency of 12.7% at 575 nm and internal quantum efficiency of 13.8% for H₂ production.
• High stability with near-unity faradaic efficiency for hydrogen evolution maintained over 6000 s.

Conclusions:

• The developed type II heterojunction photocathode significantly enhances SnS performance and stability for solar hydrogen production.
• This strategy offers a viable route for efficient and robust photoelectrochemical water splitting without sacrificial reagents.