Solar Water Splitting with a Hydrogenase Integrated in Photoelectrochemical Tandem Cells

Area of Science:

• Materials Science
• Electrochemistry
• Photocatalysis

Background:

• Hydrogenases (H2ases) are efficient catalysts for hydrogen production.
• Silicon-based photocathodes are promising for solar fuel applications.
• Integrating H2ases with semiconductor materials is key for artificial photosynthesis.

Purpose of the Study:

• To tailor a silicon photocathode for optimal hydrogenase integration.
• To achieve efficient, bias-free water splitting using a novel photocathode.
• To demonstrate an engineered Z-scheme for artificial photosynthesis.

Main Methods:

• Fabrication of a p-type Si photocathode with a hierarchical inverse opal TiO2 interlayer.
• Immobilization and wiring of hydrogenase onto the photocathode.
• Assembly of a photoelectrochemical (PEC) cell for water splitting.
• Integration with BiVO4 or PSII photoanodes.

Main Results:

• The Si|IO-TiO2|H2ase photocathode effectively drives proton reduction.
• Unassisted, bias-free water splitting was achieved for several hours.
• Proof of concept for an engineered Z-scheme using the silicon photocathode was demonstrated.

Conclusions:

• The engineered Si|IO-TiO2|H2ase photocathode is a viable component for efficient solar hydrogen production.
• This work advances the development of artificial photosynthesis systems.
• The engineered Z-scheme offers a new paradigm for light-driven water splitting.