Stability of Photocathodes: A Review on Principles, Design, and Strategies

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Semiconductor photoelectrodes enable direct solar energy conversion to chemical fuels.
• Photoelectrochemical (PEC) devices offer a promising route for solar-fuel production.
• Photoelectrode stability, particularly resistance to corrosion, remains a significant challenge hindering commercialization.

Purpose of the Study:

• To provide a fundamental understanding of photoelectrochemical reactions and photocathode principles.
• To review and analyze recent strategies for enhancing the long-term stability of photocathodes.
• To prospect the commercial application of photoelectrochemical technology.

Main Methods:

• Analysis of thermodynamic principles in photoelectrochemical reactions.
• Review of strategies including energy band alignment, layer engineering (hole transport/storage/blocking, protective/passivation), spatial decoupling, molecular catalyst grafting, surface reconstruction, and solvent effects.
• Prospective analysis of commercial applications and future research directions.

Main Results:

• Efficient photoelectrodes exist, but long-term stability is a major hurdle.
• Various strategies effectively improve photocathode stability against corrosion.
• Understanding fundamental principles is key to designing robust photoelectrode systems.

Conclusions:

• Achieving long-term stability in photoelectrodes is paramount for deploying solar-fuel production.
• Advanced strategies targeting band alignment, interface engineering, and surface modification are critical.
• Future research should focus on integrating these strategies to overcome stability challenges in photoelectrochemical devices.