Constructing Co-S interface chemical bonds over Co@NC/ZnIn₂S₄ for an efficient solar-driven photocatalytic H₂...

Area of Science:

• Materials Science
• Photocatalysis
• Heterojunction Engineering

Background:

• Efficient separation and migration of photogenerated carriers are crucial for advanced photocatalysts.
• Designing photocatalysts with intimate interfaces and strong interfacial contact is key to improving performance.
• Existing photocatalysts often suffer from charge carrier recombination, limiting their efficiency.

Purpose of the Study:

• To develop a novel Co@NC/ZnIn₂S₄ heterojunction photocatalyst with enhanced charge separation and migration.
• To investigate the role of the strong Co-S chemical bond and Schottky junction in photocatalytic activity.
• To evaluate the hydrogen evolution rate and stability of the designed heterojunction for water splitting.

Main Methods:

• Synthesis of Co@NC/ZnIn₂S₄ heterojunction.
• Characterization of the material's structure and interfacial properties.
• Photocatalytic water splitting experiments to measure hydrogen evolution rates and apparent quantum yield.
• Kelvin probe measurements to analyze interfacial electric fields.

Main Results:

• A strong Co-S chemical bond was successfully formed at the Co@NC/ZnIn₂S₄ interface.
• The heterojunction exhibited a significantly enhanced H₂ evolution rate (33.3 μmol h^-1, 6.1 times higher than pristine ZnIn₂S₄).
• The composite demonstrated excellent stability and an apparent quantum yield of 38% at 420 nm, attributed to accelerated charge separation and restricted recombination via the Schottky junction and interfacial electric field.

Conclusions:

• The in situ formation of strong chemical bonds, specifically the Co-S bond, is a highly effective strategy for designing efficient heterojunction photocatalysts.
• The engineered interface and Schottky junction in Co@NC/ZnIn₂S₄ promote interfacial charge transfer and suppress electron-hole recombination.
• This work provides a pathway for developing high-performance photocatalysts for solar fuel production through rational interface design.