THE ELECTROCHEMICALLY FORMED PALLADIUM-DEUTERIUM SYSTEM .2. INSITU NEUTRON-DIFFRACTION STUDIES

An in situ neutron diffraction study of the electrochemical formation of beta-PdD(x) in 1 M LiOD at room temperature is described. Electroly sis at relatively high overpotentials for over 200 h resulted in the f ormation of beta-PdD0.59 (a = 4.0422 angstrom), with no evidence for t he formation of a bulk phase with higher deuterium content or occupanc y of the tetrahedral sites in the face-centred cubic lattice. The form ation of a thin layer on the surface of the cathode with x > 0.59 coul d account for the observation of gas evolution once electrolysis is st opped. Evidence for hysteresis in the re-formation of palladium by oxi dation of beta-PdD(x) is also presented.