Emerging Trends in fabrication and modification techniques for bioelectrochemical system electrodes: A review

Background

Bioelectrochemical systems (BES) are specialized systems that can convert chemical energy into electrical energy using bacteria as catalysts. Electrodes play an important role in electrical energy transfer through electrochemical reactions. Electrodes are selected based on their physiochemical properties to enhance biological reactions. In microbial fuel cells (MFC), the anode is crucial because electrogens adhere to its surface and produce electrons and protons. These electrons and protons are absorbed by the cathode surface to generate bioelectricity. Numerous substances, like carbon based, metal based, conductive polymers and gas diffused materials, can be used as anodes and cathodes.

Method

To improve their physiochemical properties, conductive polymers such as polypyrrole (PPy) and polyaniline (PANI) are combined with other substances. In MFCs', both anode and cathode are important components. In anodic location, oxidation occurs, which produces electrons and protons. A reduction reaction produces molecules of water at the cathode location. Various materials can be utilised to create cathodes and anodes. Materials such as carbon based, CC, graphite and metals can be utilized to create anodes. Materials based on carbon, such as CC, carbon black, and so on, as well as materials based on metal and gas diffusion can be employed to create cathode. The electrode's surface material layer is created using electrode manufacturing techniques. Screen printing, electrochemical deposition, and chemical vapor deposition are the most of commonly used methods. Applications for BESs are numerous and include bioremediation, biosensors, MFCs, and microbial electrolysis cells (MECs). Various waste products are used in anodic chambers of MFCs to create electrical energy. Methane, green hydrogen, formic acid, hydrogen peroxide, and other value-added compounds are produced by MECs, a modified form of MFCs. Toxic contaminants in BESs can be removed and transformed into products with increased value using bioremediation. Biosensors are essential tools for physiochemical parameter monitoring in real time in the current world. MFC is regarded as a biosensor for contrasting the energy generated with many other factors.

Significant Findings

This paper mainly focuses on the different materials of electrodes that are being used and fabrication techniques that enhance the productivity of electrodes in BES to reduce the organic waste load and generate bioelectricity.