Light-Driven Overall Water Splitting Enabled by a Photo-Dember Effect Realized on 3D Plasmonic Structures

Area of Science:

• Materials Science
• Photochemistry
• Nanotechnology

Background:

• Solar energy conversion, including solar cells and water splitting, faces challenges in separating photoexcited charges.
• Efficient charge separation is crucial for improving the performance of photoelectric devices.

Purpose of the Study:

• To develop a method for long-range electric polarization to enhance charge separation in solar energy applications.
• To demonstrate sunlight-driven overall water splitting using a novel plasmonic structure combined with semiconductor particles.

Main Methods:

• Fabrication of a three-dimensional silver (3D-Ag) structure to induce asymmetric surface plasmon localization and electric polarization.
• Integration of 3D-Ag with commercial semiconductor particles (ZnO, CeO2, TiO2, WO3) for photocatalytic water splitting.
• Investigation of the photo-Dember effect for charge separation and photocatalytic activity measurement.

Main Results:

• Achieved long-range electric polarization (∼1.5 μm period) via the photo-Dember effect on the 3D-Ag structure.
• Efficiently separated photogenerated charges, enabling sunlight-driven overall water splitting with 3D-Ag and semiconductor composites.
• Demonstrated excellent catalytic stability (>30 h) for 3D-Ag+ZnO, 3D-Ag+CeO2, and 3D-Ag+TiO2 systems.
• Observed superior oxygen generation with 3D-Ag+CeO2 compared to systems using sacrificial reagents.

Conclusions:

• The plasmon-mediated charge separation strategy using 3D-Ag effectively enhances photoelectric energy conversion efficiency.
• This approach provides a viable pathway for improving photovoltaics and photocatalysis, particularly for water splitting.
• The developed 3D-Ag structure offers a stable and efficient platform for visible-light-driven photocatalysis.