Photosystem II-Carbon Nitride Photoanodes for Scalable Biophotoelectrochemistry

Area of Science:

• Biotechnology
• Electrochemistry
• Photosynthesis

Background:

• Photosystem II (PSII) holds potential for sustainable bioenergy but faces challenges in electrode integration.
• Developing efficient interfaces for PSII is crucial for practical bioelectrochemical applications.

Purpose of the Study:

• To create a scalable method for wiring Photosystem II (PSII) with electrodes for biophotoelectrochemical applications.
• To develop large-area photoanodes for efficient water oxidation and bioelectricity generation.

Main Methods:

• Protonated macroporous carbon nitride (MCN) was synthesized as a support material.
• A spray-freeze method was employed to wire PSII with MCN, creating large-area photoanodes.
• A bias-free biophotoelectrochemical (BPEC) device was constructed using MCN-PSII photoanodes and a carbon nanotube cathode.

Main Results:

• Large-area MCN-PSII photoanodes (up to 33 cm²) were produced for biophotoelectrochemical water oxidation.
• Efficient interfacial charge transfer resulted in photocurrents in the mA range with high Faradaic yield (93.5 ± 8.5%) over 5 hours.
• An array of eight tandem BPEC cells (72 cm²) successfully powered low-power electronics, demonstrating practical energy generation.

Conclusions:

• The study presents an efficient bioelectrode fabrication method using PSII and MCN.
• This work highlights the potential of PSII-based semi-artificial systems for biophotoelectrochemical (BPEC) and biophotovoltaic applications.
• The developed technology offers a pathway for sustainable bioelectricity and fuel generation.