Monte Carlo Simulation of Hydrogen Absorption in Palladium and Palladium-Silver Alloy

Russian Physics Journal - The paper presents Monte Carlo simulation of the hydrogen absorption in palladium and palladium-silver alloy of the composition PdxAg1–x (x = 0.7–0.9) at...     

Modifying the surface of a hydrogen permselective palladium–silver membrane

Thin films of Pd–23% Ag composition are obtained by means of magnetron sputter deposition. The surfaces of the films are modified via the electrolythic deposition of finely divided palladium. The hydrogen permeabilities of samples of membranes (both smooth and modified with palladium black) are compared. A marked increase in the hydrogen permeability of the modified membrane is observed, compared to the smooth membrane. The dependence of the rate of hydrogen fluence on the excess pressure is approximated by a curve of the first order, demonstrating the limitations of the process of hydrogen permeation by hydrogen superficial dissociation.     

Synthesis and Gas-Transport Parameters of Membranes Modified by Star-Shaped Palladium Nanocrystallites

Doklady Physics - Methods for modifying the surface of Pd–23%Ag alloy films and synthesizing nanostar- and nanopore-type palladium coatings, which enhance the hydrogen transport rate, were...     

Kinetic Characteristics of Hydrogen Transfer Through Palladium-Modified Membrane

Russian Physics Journal - The paper deals with hydrogen transfer through Pd-23%Ag alloy membrane, the surface of which is modified by the electrolytic deposition of highly dispersed palladium. The...     

Influence of the rhenium carrier in eluate of Re-188 on its binding with potassium-sodium salt of hydroxyethylidene biphosphonic acid

The results of investigation of the regularity of ¹⁸⁸Re binding with KNaHEDP and hydrolysis of the complex compound (¹⁸⁸Re-KNaHEDP) have shown that its quality depends to a considerable extent on the reaction conditions. Concentrations of a reducing agent (Sn²⁺) and stable rhenium in the ¹⁸⁸Re eluate, as the carrier, influence essentially the rate of formation and stability of ¹⁸⁸Re complex with KNaHEDP. The results of the kinetic investigations of the ¹⁸⁸Re-KNaHEDP complex formation prove that the reaction character bears a direct relationship to the concentrations of the complexing agent (Re) and the reducer (Sn²⁺). The higher ratio of Re⁷⁺: Sn²⁺ concentrations, the more effectively ¹⁸⁸Re binds with KNaHEDP. The obtained results prove that for ¹⁸⁸Re binding with KNaHEDP with the efficiency not less than 95% the optimum concentration of stable rhenium in the reaction mixture is 0.54×10⁻⁶ mol·ml⁻¹ (0.1 mgMml⁻¹) and the ratio of Re⁷⁺: Sn²⁺ concentrations should not be lower than 10: 1.     

Hydrogen Transport through Palladium-Coated Niobium Membranes

Russian Physics Journal - The paper presents the synthesis of a nanocrystalline coating for modification of the Pd?Nb?Pd composite membrane surface. The nanostructured palladium coating...     

Gas Transmission Properties of Pd–Ag Membranes Coated with Modifying Layer

Russian Physics Journal - The paper proposes the manufacturing methods for modifying coatings for gas-diffusion membranes made of palladium-silver alloy comprising 23% Ag. Highly developed surface...     

The Influence of a Crystallographically Atypical Pentagonal Nanostructured Coating on the Limiting Stage of Low-Temperature Hydrogen Transport through Pd–Cu Membranes

Doklady Physics - A new approach to the acceleration of the surface processes of hydrogen transport through Pd–40%Cu membranes by depositing a developed catalytic coating consisting of...     

Hydrogen Permeability of a Foil of Pd–Ag Alloy Modified with a Nanoporous Palladium Coating

Thin films with the composition Pd–23% Ag are obtained via magnetron sputtering. The magnetron sputtering of Pd–50% Zn films with subsequent diffusion annealing and etching of the active component is used to modify the surfaces of palladium–silver films to improve their hydrogen permeability. Modifying the surfaces of the resulting Pd–Ag films using a nanoporous palladium coating with a predominant distribution of particles ranging from 0 to 50 nm allows a hydrogen flux density of up to 0.4 mmol s^?1 m^?2 to be achieved for sufficiently thin palladium membranes (<10 μm) under conditions of low temperature (<90°C) and pressure (<0.6 MPa). Experimental evidence is gathered that under these conditions, the velocity of hydrogen transport is limited by dissociative–associative processes at membrane boundaries and can be greatly (by an order of magnitude) increased, due to acceleration of the limiting stage of the process via the formation of a palladium nanoporous coating on the film’s surface.