Surface area expansion of electrodes with grass-like nanostructures and gold nanoparticles to enhance electricity generation in microbial fuel cells

Microbial fuel cells (MFCs) have applications possibilities for wastewater treatment, biotransformation, and biosensor, but the development of highly efficient electrode materials is critical for enhancing the power generation. Two types of electrodes modified with nanoparticles or grass-like nanostructure (termed nanograss) were used. A two-chamber MFC with plain silicium electrodes achieved a maximum power density of 0.002 mW/m2, while an electrode with nanograss of titanium and gold deposited on one side gave a maximum power density of 2.5 mW/m2. Deposition of titanium and gold on both sides of plain silicium showed a maximum power density of 86.0 mW/m2. Further expanding the surface area of carbon-paper electrodes with gold nanoparticles resulted in a maximum stable power density of 346.9 mW/m2 which is 2.9 times higher than that achieved with conventional carbon-paper. These results show that fabrication of electrodes with nanograss could be an efficient way to increase the power generation.