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This study applies a dual bubble layer model and the Hydrogen Evolution Reaction (HER) test protocol originally developed by Kitajima et al., to both polished flat and 3D microporous Dynamic Hydrogen Bubble Template (DHBT) nickel surfaces. The results showed that bubble-induced diffusion resistance was present on both surface types, supporting the development of a universal, non-destructive protocol for assessing bubble management performance. By focusing on bubble diffusion impedance as a primary performance indicator, the study isolated bubble dynamics from electrochemically active surface area (ECSA) effects, which is often overlooked in traditional assessments. Time-domain transformations of impedance data helped identify the components of an equivalent circuit model, with porous DHBT surfaces exhibiting an additional charge transfer process compared to flat surfaces. Using photographic evidence and Nyquist plot observations, we define three distinct stages in the HER process: (1) Initial discrete bubble formation with charge transfer dominance, (2) emergence of hydrogen oxidation product (H OPD ) and bubble accumulation 17, and (3) formation of a dense bubble layer. Circuit fitting revealed that bubble diffusion resistance was highly dependent on surface morphology, with polished surfaces exhibiting greater resistance than porous ones. Diffusion resistance correlated with bubble layer thickness and scales with the square root of applied current density.
Wang et al. (Fri,) studied this question.