Hydrogen systems solubility

Palladium hydride is not a stoichiometric chemical compound but simply a metal in which hydrogen is dissolved and stored in solid state, in space between Pd atoms of crystal lattice of the host metal. Relatively high solubility and mobility of H in the FCC (face-centered-cubic) Pd lattice made the Pd H system one of the most transparent, and hence most studied from microstructural, thermodynamic, and kinetic points of view. Over the century that followed many metal-hydrogen systems were investigated while those studies were driven mostly by scientific curiosity. Researchers were interested in the interaction of hydrogen molecule with metal surfaces adsorption and diffusion into metals. Many reports on absorption of in Ni, Fe, Ni, Co, Cu, Pd, Pt, Rh, Pd-Pt, Pd-Rh, Mo-Fe, Ag-Cu, Au-Cu, Cu-Ni, Cu-Pt, Cu-Sn, and lack of absorption in Ag, Au, Cd, Pb, Sn, Zn came from Sieverts et al. [30-33]. 

The essential requirements for hydrogen storage in solids are that it be (a) high H-mass density (b) high H-volume density (c) appropriate pressure, temperature stability (d) reversible absorption/desorption. The results of research in the field of hydrogen solubility in the metal-hydrogen systems and carbon nanostructures are presented in this paper. 

Synthesis of the first water-soluble catalyst complexes was reported in 1973 [3] and was based on the use of sulfonated triphenylphosphine to replace TPP. The sulfonated derivative was found to stabilize the lower oxidation states of a number of transition metals such as Rh, Ru, Ir, Pt, Ni, and Cu in aqueous systems and these water-soluble catalysts facilitated hydrogenation of soluble substrates like pyruvic acid. 

Bleach Stabilization. When added to hydrogen peroxide based bleaching systems, soluble silicates are known to significantly enhance bleach performance. Many hypotheses have been put forth to explain this process, including buffering, peroxysilicate complex formation, and modification of peroxide equilibrium. However, the most recent and plausible explanation is that the silicate inactivates iron and manganese species which catalyze peroxide decomposition (13). 

Palladium is one of the six transition metals that are also known as the platinum metals and has high hydrogen solubility to make it attractive as a hydrogenation catalyst and hydrogen separation membrane. The early works of the palladium as a hydrogen separation membrane is mostly concentrated on palladium foils. An excellent review on hydrogen permeation in palladium and palladium hydrogen systems was presented in detail by Lewis [1]. 

Tritium shows a similar solution behaviour as deuterium. The constants of solubility in the sodium-hydrogen system seem to need further improvement. 

With the use of our analysis apparatus which could detect a condensable impurity in hydrogen down to 0.5 ppm, we could not find any measurable solubility of oxygen in liquid hydrogen. Conditions for these tests were identical with those for the nitrogen-hydrogen system. 

Heat Transfer to Boiling Liquid Nitrogen and Hydrogen Flowing Axially Through Narrow Annular Passages (3) 375 Hydrocarbon- Oxygen Systems Solubility (4) 11... 

One of the most thoroughly investigated ternary metal-hydrogen systems is Pd-Ag-H. It is experimentally known ) that addition of Ag to Pd favours hydrogen absorption at low hydrogen concentrations and reduces the maximum solubility at higher pressures. These trends are well reproduced by the calculated isotherms shown in Figs.7 a,b for PdQ o... 

In this paper the solubility of hydrogen in ordered and disordered forms of several substitutional palladium alloys will be discussed. Some new data will be presented for the Pdr Ge and Pd Mn alloy-hydrogen systems,... 

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