Polyaniline-Facilitated Direct Electron Transfer from Photosystem II on Inverse-Opal CeO₂

Area of Science:

• Biohybrid systems
• Artificial photosynthesis
• Materials science

Background:

• Natural photosystem II (PSII) is the sole enzyme capable of water oxidation.
• Integrating PSII with artificial electrodes is key for semi-artificial photosynthesis and solar energy conversion.
• Achieving uniform PSII distribution and efficient charge transfer are critical challenges.

Purpose of the Study:

• To develop an efficient biointerface for PSII integration with artificial electrodes.
• To enhance charge transfer and visible-light absorption for improved solar energy conversion.
• To engineer a robust photoanode for sustained oxygen evolution.

Main Methods:

• Growing an inverse-opal CeO2 (IO-CeO2) scaffold directly on an electrode.
• Utilizing polyaniline (PANI) electrodeposition for PSII attachment.
• Characterizing the photoanode's performance in a direct electron transfer system.

Main Results:

• The PANI interlayer improved PSII loading, alignment, and visible-light absorption.
• A Z-scheme/type-II tandem heterojunction was established, enhancing electron transfer.
• A photocurrent of 5.9 ± 0.1 μA cm⁻² was achieved.
• A 9 cm² PSII-PANI2-IO-CeO2 photoanode showed a 76% increase in oxygen production.

Conclusions:

• The developed biointerface engineering approach offers simple design rules for efficient biohybrid systems.
• This method significantly enhances PSII performance for artificial photosynthesis.
• The approach is applicable to other biohybrid systems for solar energy conversion.