Oxide-derived Pd electrodes are prepared from PdO-coated titanium electrodes (fabricated by thermal decomposition) after polarization at 0 V (vs. reversible hydrogen electrode, RHE) for 30 min. Hydrogen sorption/desorption at/within these electrodes as well as that at ordinary bulk Pd were compared by cyclic voltammetry. In contrast to the results for a bulk palladium electrode, both hydrogen adsorption and absorption peaks are clearly observed on the negative CV sweeps and hydrogen evolution commences after the hydrogen absorption becomes saturated for the oxide-derived Pd electrodes in NaOH and H2SO4 solutions. Different sources of proton supply (H+/H3O+ in acid and H2O in base), HSO4, SO42- adsorption, and hydrogen damage of the Pd lattice structure account for the different responses in acidic and basic solutions. Surface morphologies of the bulk Pd and the oxide-derived Pd electrodes (where oxide is reduced in either acidic or basic solutions) were examined by scanning electron microscopy to elucidate the effect of surface roughness.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry