Influence of atmospheric oxygen on hydrogen detection on Pd using Kelvin probe technique

Influence of oxygen concentration in the measurement atmosphere on detection of hydrogen using Kelvin probe was studied. The studied material was a 100-μm-thick palladium foil, which was mounted in a 3D printed electrochemical flow cell. The used setup enables hydrogen loading with in-situ contact potential measurement of the hydrogen exit side of the Pd electrode. The hydrogen loading and unloading procedure, including insertion of different amounts of hydrogen into the Pd membrane and recording resulting values of contact potential difference, was performed at distinct oxygen concentrations ranging between 1 and 80 vol%. An increasing amount of oxygen in the atmosphere surrounding the hydrogen-loaded Pd electrode resulted in an accelerated removal of hydrogen from the Pd. The kinetics of this reaction was studied based on Kelvin probe measurements, and a reaction mechanism is discussed.