Abstract
The dynamics of hydrogen-induced vacancies are the key for understanding various phenomena in metal–hydrogen systems under a high hydrogen chemical potential. In this study, a novel dry-electrolysis experiment was performed in which a hydrogen isotope was injected into a Pd cathode and time-resolved in situ monochromatic X-ray diffraction measurement was carried out at the Pd cathode. It was found that palladium-hydride containing vacancies forms multiple phases depending on the hydrogen chemical potential. Phase separation into vacancy-rich, vacancy-poor, and moderate-vacancy-concentration phases was observed when the input voltage was relatively low, i.e., ∼0.5 V. The moderate-vacancy-concentration phase may be attributed to Ca7Ge or another type of super-lattice Pd7VacH(D)8. Transition from the vacancy-rich to the moderate-vacancy-concentration phase explains the sub-micron void formations without high temperature treatment that were observed at the Pd cathode but have never been reported in previous anvil experiments.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have