3D-printed hierarchical pillar array electrodes for high-performance semi-artificial photosynthesis.

Area of Science:

• Bioelectrochemistry
• Renewable Energy
• Nanotechnology

Background:

• Semi-artificial photosynthesis offers a sustainable route for bio-electricity and fuel generation.
• Optimizing the electrode-biomaterial interface is crucial for high biophotoelectrochemical performance.

Purpose of the Study:

• To develop and evaluate hierarchical electrode structures for enhanced bio-electrode interfaces.
• To investigate the impact of electrode design on energy and electron transfer for photosynthesis-based energy generation.

Main Methods:

• Aerosol jet printing of indium tin oxide nanoparticle-based micropillar array electrodes.
• Fabrication of electrodes with varying heights and submicrometre surface features.
• Integration with the cyanobacterium Synechocystis sp. PCC 6803 for photocurrent measurements.

Main Results:

• Micropillar array electrodes with microbranches significantly improved biocatalyst loading, light utilization, and electron flux.
• Photocurrent densities nearly doubled compared to state-of-the-art porous structures.
• Electrodes with 600 µm height achieved photocurrent densities of 245 µA cm⁻² and external quantum efficiencies up to 29%.

Conclusions:

• Hierarchical 3D electrode design using aerosol jet printing is effective for enhancing biophotoelectrochemical performance.
• Optimized electrode structures enable more efficient harnessing of bio-energy from photosynthesis.
• This work provides novel tools for designing 3D electrodes for sustainable bio-energy applications.