Solar hydrogen production through ambient-pressure seawater splitting.

Area of Science:

• Materials Science
• Photocatalysis
• Renewable Energy

Background:

• Polymeric carbon nitride shows potential for solar hydrogen production but faces scalability challenges.
• Current methods often require expensive vacuum conditions and limited freshwater resources.

Purpose of the Study:

• To develop a molecular design for efficient photocatalytic seawater splitting under ambient conditions.
• To overcome the limitations of traditional carbon nitride materials for scalable green hydrogen production.

Main Methods:

• Synthesized ultrathin carbon nitride nanosheets covalently linked to electron-donating pyrene units via π-bridges.
• Utilized in situ spectroscopic and electrochemical analyses to study intramolecular electron transfer and electric fields.
• Performed theoretical calculations to understand ion adsorption and hole consumption mechanisms.

Main Results:

• Donor-π-acceptor frameworks with biphenyl π-bridges exhibited reduced exciton binding energy and prolonged charge-separated states.
• Demonstrated efficient intramolecular electron transfer and a strengthened built-in internal electric field.
• Achieved a hydrogen evolution rate of 134 mmol h⁻¹ g⁻¹ for photocatalytic seawater splitting under natural sunlight and ambient pressure.

Conclusions:

• The molecular design strategy effectively enhances photocatalytic seawater splitting.
• This approach promotes the commercialization of green hydrogen production by utilizing seawater and ambient conditions.