In situ imaging study reveals multi-bubble dynamics on nickel-based electrodes during hydrogen evolution, indicating an effective optical approach to quantify catalyst surface blockage.
Key Points
To develop an in situ polarization imaging technique for real-time visualization and quantitative tracking of multi-bubble dynamics and interfacial coverage on nickel-based electrodes during the hydrogen evolution reaction.
Constructed a prism-coupled, dual-camera synchronous polarization imaging system to measure degree of polarization (DOP) maps on electrode surfaces.
Formulated an apparent coverage parameter (θ DOP) and validated it against reference bubble coverage up to approximately 50% coverage.
Evaluated bare Ni and NiMo-loaded Ni electrodes under scan rate variations and matched current densities ranging from 1 to 50 mA/cm².
Demonstrated direct quantitative correspondence between the polarization response (θ DOP) and true bubble coverage up to roughly 50% surface coverage.
Observed that increasing overpotential and higher scan rates intensified multi-bubble dynamics, altering interfacial coverage evolution.
Identified distinct multi-bubble morphologies and detachment behaviors between bare Ni and NiMo-loaded Ni electrodes across matched current densities from 1 to 50 mA/cm².