MICROBIAL ELECTROLYSIS CELLS: ELECTROCATALYSTS AND CHARACTERIZATION METHODS - A REVIEW

The growing global energy demand and depletion of fossil fuels require the development of sustainable alternatives. Hydrogen is widely recognized as a clean energy carrier due to its high energy density and environmentally benign combustion, producing only water. However, the high cost of hydrogen production remains a major barrier to its large-scale application, which stimulates research into novel production methods. One of the newest methods in this direction is biocatalyzed electrolysis, in which, along with hydrogen production, simultaneous purification of biodegradable waste products is carried out. Unlike traditional electrolyzers, the oxidation of the substrate is facilitated with the help of specific microorganisms capable of transferring extracellular electrons, generated by their catabolite processes to the anode of bioelectrochemical systems. One of the most important advantages of microbial electrolysis cell (MEC) is that they use substrates from renewable sources and are characterized by high efficiency. The reaction in which hydrogen is released at the cathode is inherent in several industrial electrolysis processes with aqueous electrolytes. The choice of cathode material has a strong influence on the rate of hydrogen release. A crucial factor for the practical implementation of MEC is to find effective cathode materials for operation at neutral pH, since electrogenic microorganisms are used.This paper reviews the basic principles of microbial electrolysis cell, as well as various methods for physicochemical and electrochemical characterization of potential cathode materials for bioelectrochemical hydrogen production.