Mechanism of hydrogen bubble behavior at different reaction stages of high-current PEMWE during pulsed dynamic electrolysis

Hydrogen production from fossil fuels is not an ideal choice. Proton exchange membrane water electrolysis (PEMWE), due to its clean and efficient hydrogen production characteristics, shows great promise in the field of renewable energy. Although significant progress has been made, PEMWE still faces challenges under high-current conditions, such as bubble accumulation, polarization effects, and low energy efficiency. Conventional constant voltage electrolysis (CE) struggles to effectively mitigate these issues, making the exploration of novel enhancement technologies crucial. Pulsed dynamic electrolysis (PDE), by efficiently coordinating bubble release with reaction/transport processes, is expected to solve the above challenges. Driven by equilibrium voltage of 1.4 V, the hydrogen production rate of PDE (123.3 mL h⁻¹) is significantly higher than that of the CE condition (2.5 mL h⁻¹), showing excellent low-energy hydrogen production advantages. At high current of 2 A, PDE reduces electricity consumption by ∼4 % compared to the CE condition. The proposed new mechanism of PDE, utilizing the relaxation effect generated by periodic pulsed intermittent voltage, reduces the growth dynamics of microbubbles on the membrane electrode assembly (MEA) electrode surface, thereby promoting the bubble desorption and replenishment of reactants. This mechanism shows significant advantages during the equilibrium and onset voltage stages of PEMWE. PDE is regarded as a promising novel enhancement technology for hydrogen production via electrolysis and holds potential for broader electrocatalytic applications.