Microbial electrolysis cell is essentially a faradaic electrochemical device that functions on the separated redox between its electrodes. The primary driving force exists in the performed reaction at the electrodes. The reaction itself is governed by thermodynamics, kinetics, and mass transfer. Utilizing catalyst can ease the kinetics of the reaction and enhance its rate. In MEC, the anode relies on biocatalyst ability to convert substrate into electrons and protons. On the other hand, the cathode relies on hydrogen evolution reaction (HER). The reaction mechanism and testing have been studied vigorously and are continuously improved. Its catalyst has many classes including noble metals, transition metal-based constructs, enzymes, and microbes.