A Fully Artificial Molecular-Based Photoelectrochemical Cell Enabling Overall Water Splitting by Combining a...

Area of Science:

• Artificial photosynthesis
• Molecular-based systems
• Solar water splitting

Background:

• Developing efficient artificial photosynthesis for solar water splitting is crucial.
• Molecular-based photoelectrochemical cells (MPECs) are promising but challenging.
• Current systems often require complex strategies like the Z-scheme.

Purpose of the Study:

• To construct a fully artificial molecular-based photoelectrochemical cell (MPEC).
• To achieve efficient solar water splitting using visible light.
• To demonstrate a high solar-to-hydrogen conversion efficiency in an MPEC.

Main Methods:

• Fabricated a mesoporous TiO2 photoanode with a ruthenium photosensitizer and a ruthenium-based water oxidation catalyst.
• Developed a mesoporous TiO2 dark-cathode with a platinum porphyrin water reduction catalyst.
• Utilized visible-light irradiation on the photoanode to drive water splitting.

Main Results:

• The MPEC successfully split water into H2 and O2 in a 2:1 molar ratio with high Faradaic efficiencies.
• Achieved a record applied-bias-compensated solar-to-hydrogen (AB-STH) conversion efficiency of 0.06% for fully artificial MPECs.
• Demonstrated efficient water splitting under visible light without a Z-scheme.

Conclusions:

• A fully artificial molecular-based photoelectrochemical cell can efficiently perform solar water splitting.
• The developed MPEC sets a new benchmark for solar-to-hydrogen conversion efficiency in artificial systems.
• Single-step photoreaction systems are viable for artificial photosynthesis, reducing complexity.