Numerical Analysis of the Effect of Charge Transfer Coefficient (CTC) on Bubble Evolution of Polymer Electrolyte Membrane (PEM) Electrolyzer

Abstract

There is a growing concern on the need to enhance the current density of alkaline electrolysis without compromising reduction in efficiency. During the operation of alkaline electrolyzers, a portion of the electrode surface is covered with cloud of bubbles. The bubbles increase ohmic resistance and activation overvoltage of the electrolyte. This study aims to investigate the effect of charge transfer coefficient (CTC) on the voltage characteristics of PEM electrolyzer. Matlab was used to simulate the equations. The simulation result shows that CTC values at the anode electrode range between 0.807 and 1.035. Interestingly, at CTC of 0.5 and 0.2 for anode and cathode, the operating voltage at 1 A/cm2 was observed to be 2.0 V. Also at CTC of 2 and 0.5 for anode and cathode, respectively, there was a significant drop in operating voltage up to 1.62 V with a current density of 1 A/cm2, this accounts for about 27% reduction in operating voltage

Review on Bubble Dynamics in Proton Exchange Membrane Water Electrolysis: Towards Optimal Green Hydrogen Yield

“…With an increase in the number of bubbles on the electrode, the activation overpotential also increases to overcome the resistance offered by the bubbles. Based on the numerical study for the effect of bubble evaluation performed, low temperatures (30 • C and 60 • C) require higher activation overpotential, whereas high temperatures (90 • C) require less additional voltage energy when there is sufficient bubble coverage [97]. In many industrial processes, an excessive number of bubbles on the electrode surface might impede the proper reaction of the reactants and the product sides [98].…”