The Quantities Affecting the Bubble Coverage of Gas-Evolving Electrodes

The fractional bubble coverage is the leading quantity required for information on the actual current density of gas-evolving electrodes at a given nominal current density I/A. As confirmed by experiments, the bubble coverage increases with increasing current density, provided the values are sufficiently small. At large values of the bubble coverage, both variables develop in opposite directions: The nominal current density decreases as the bubble coverage increases. However, the current density is not the single quantity acting on the bubble coverage. Additionally numerous other quantities impact. They are traced up and their interferences are discussed. Particularly their impact on the interrelation of bubble coverage and current density is studied. The outcome is significant particularly for understanding real processes occurring at elevate electrode potentials likewise in laboratory and in industrial electrochemical reactors.