Design and Fabrication of Novel Photo-Bioelectrochemical fuel Cells for Direct Electricity Production by Harvesting Light Energy

Photo-bioelectrochemical fuel cells (also known as bioelectrochemical fuel cells and microbial fuel cells) are one of the growing energy conversion technologies because of their natural abundance and environmental friendliness. In photo-bioelectrochemical fuel cell systems where biological organisms are used, the electrons are generated as a result of photolysis of water into oxygen and hydrogen that are transferred to the anode. The cathode surface undergoes a chemical reaction which alters the potential in the solution. This potential difference between the two electrodes causes the electrons to move from anode to cathode. The flow of electrons carried out by light illumination can be used as an electric energy by applying an external circuit. Herein, a novel photo-bioelectrochemical fuel cell will be designed and constructed that will generate electricity using algae and cyanobacteria under light illumination. Moreover, a modified electrode will also be prepared to provide large photo-currents for longer time by destroying reactive oxygen species (ROS) that are released during photosynthesis. Superoxide dismutase and catalase enzymes will be immobilized on the anode surface to obtain a functionalized electrode with better bioelectrochemical properties. In addition, the bilirubin oxidase bound cathode, which is an oxygen-reducing enzyme, will also be used. Photosynthetic microorganisms will be injected in to the cell and grown on the surface of the anode to form a biofilm. The photosynthesis will be activated as soon as the light is shined on the cell that will generate photo current through electron transfer reaction. The oxygen that is released during photosynthesis on the anode surface will be reduced back to the water by the cathode, and the photo-current production is maintained continuously in the fuel cell. Moreover, the surface of the photo anode will be modified using metal oxide nano particles to provide a better and stable platform for biofilm to harvest sunlight more efficiently. The synthesis of these nano particles will be carried out using a novel method of pulsed laser ablation in liquid (PLAL). The nanomaterial synthesis using PLAL has proven to be facile, precursor free and environment friendly for the synthesis of pure and composite nanostructured materials. The major advantage of PLAL process is that the size and shape of the particles can be controlled by varying different parameters such as laser intensity, wavelength, pulse duration, pH of the solution, surfactants and introducing external fields.