Transient Simulation of Gas Bubble Evolution and Overpotential Dynamics for the Hydrogen Evolution Reaction

Green hydrogen production via aqueous electrolysis faces substantial cost, stability, and efficiency challenges that impede widespread adoption. These challenges are directly linked to intricately coupled electrochemical and fluid dynamic processes occurring at the electrode–electrolyte interface. In particular, gas bubble nucleation, growth, and detachment significantly affect electrochemical ohmic, activation, and concentration overpotentials. Herein, a multi-dimensional, experimentally validated simulation captures the transient evolution of hydrogen gas bubbles and their effects on electrochemical reaction overpotentials during the hydrogen evolution reaction (HER) on a polycrystalline Pt electrode. The model spans the two distinct voltage regimes of −100 mV (≈−41 mA cm–2) and −700 mV (≈−550 mA cm–2) vs the reversible hydrogen electrode (RHE). The two voltages represent systems with varying overpotential contributions and hydrogen generation rates. This first transient, unified framework merges electrochemistry and fluid dynamics, offering a robust platform for visualizing and optimizing green hydrogen production across diverse operating conditions and devices.