Palladiumhydrides

Palladium hydrides are binary compounds formed between palladium and hydrogen. When palladium metal is exposed to hydrogen gas, hydrogen atoms can diffuse into the palladium lattice, forming a solid solution or distinct hydride phases. The most common and well-studied palladium hydride is PdHₓ, where x represents the atomic ratio of hydrogen to palladium. This ratio can vary significantly depending on the hydrogen pressure and temperature. At low hydrogen concentrations, palladium forms a face-centered cubic (FCC) solid solution phase, often denoted as α-phase. As the hydrogen concentration increases, a second FCC phase, the β-phase, forms. These two phases can coexist over a range of compositions.

The formation of palladium hydrides is a reversible process. Hydrogen can be absorbed by palladium and subsequently released, which makes palladium a crucial material for hydrogen storage and purification technologies. The hydrogen absorption capacity of palladium is remarkably high. Palladium hydrides exhibit unique physical and chemical properties that differ from pure palladium, including changes in electrical resistivity, magnetic susceptibility, and mechanical strength. Research into palladium hydrides continues to explore their potential applications in areas such as catalysis, sensors, and energy storage. Understanding the phase diagram and the thermodynamics of hydrogen absorption in palladium is key to optimizing these applications.