Nanoparticle decorated anodes for enhanced current generation in microbial electrochemical cells

Area of Science:

• Electrochemistry
• Materials Science
• Microbiology

Background:

• Microbial electrochemical cells (MECs) require efficient anode materials to increase current output.
• Nanoparticle decoration of anodes is a potential strategy to enhance MEC performance.

Purpose of the Study:

• To develop and evaluate gold (Au) and palladium (Pd) nanoparticle-decorated graphite anodes for MECs.
• To investigate the correlation between nanoparticle characteristics and anode performance.

Main Methods:

• Fabrication of Au and Pd nanoparticle-decorated graphite anodes.
• Evaluation of anodes in a multi-anode MEC using Shewanella oneidensis MR-1.
• Analysis of current density, particle size, shape, and density.

Main Results:

• Au-decorated anodes achieved up to 20-fold higher current densities compared to plain graphite.
• Pd-decorated anodes showed 50-150% higher current densities than the control.
• Positive linear correlation between current density and nanoparticle size (Feret's diameter, area).
• Negative correlation between current density and particle circularity.

Conclusions:

• Nano-decoration significantly enhances microbial anode performance in MECs.
• Nanoparticle chemical composition, size, and shape are key factors determining performance enhancement.
• Particle size and shape are more critical than particle density for improved current output.