About the Nature of Excessive Gas Evolution in the Case of Electrochemical Hydrogenation of Palladium in an Alkaline Solution

Abstract

The gas evolution process on fully hydrogenated Pd (H : Pd = 0.73) cathodes is studied in a 1 M solution of NaOH at ambient temperature. A phenomenon of spontaneous gas evolution on the surface of PdH after electrolysis and transfer of the sample into a burette with a 1 M solution of NaOH or distilled water is discovered. The volume of the gas that spontaneously evolved on the surface of PdH is 0.22–0.24 cm³/cm² in a 1 M solution of NaOH and 0.40–0.43 cm³/cm² in distilled water. It is proposed that the spontaneously evolving gas is not hydrogen from PdH, but results from the cavitation process.