Concentrated Solar Light Photoelectrochemical Water Splitting for Stable and High-Yield Hydrogen Production

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Photoelectrochemical water splitting converts solar energy to hydrogen fuel.
• Low photogenerated charge carriers limit H2 production under standard sunlight.
• Concentrated solar light increases yield but challenges photoelectrode stability.

Purpose of the Study:

• To develop an efficient and stable photoelectrode for high-yield solar to H2 conversion under concentrated light.
• To investigate the use of platinum nanoparticles on single crystalline gallium nitride nanowires for photoelectrochemical water splitting.

Main Methods:

• Loading platinum nanoparticles (Pt NPs) onto single crystalline GaN nanowires (NWs) grown on n+-p Si photoelectrodes.
• Testing photoelectrode performance and stability under concentrated solar light.
• Analyzing the effect of Pt NP detachment and redeposition on stability and efficiency.

Main Results:

• Pt NPs with epitaxial relation to GaN NWs showed stable anchoring despite initial H2 gas bubbling.
• Redeposition of Pt NPs significantly improved photoelectrode stability.
• The optimized photoelectrode maintained an onset potential >0.5 V vs RHE and photocurrent density >60 mA cm-2 for over 1500 hours.

Conclusions:

• Single crystalline GaN nanostructures with Pt cocatalysts offer a promising platform for efficient and stable solar hydrogen production.
• The heterointerface between Pt and GaN is crucial for high-yield solar to H2 conversion under concentrated solar irradiation.