Hydrogenation of HOPG-Supported Gold Nanoparticles: Surface or Volume?

The hydrogenation features of gold nanoparticles deposited on highly oriented pyrolytic graphite were determined, and composite nanostructures consisting of pure and hydrogenized gold were synthesized. Methods of scanning tunneling microscopy and spectroscopy have been successfully used to probe the bottom of the conductive band and to determine the shape of the electron energy barrier in hydrogenized gold. Considering models of surface and volume hydrogenation, we have shown that no hydrogen dissolution occurred in gold nanoparticles, but all changes in their electronic structure were associated with surface processes. The results of the quantum chemical simulation also corresponded with this conclusion.

Ab initio моделирование энергии растворения и энергии связи водорода с 3sp-, 3d- и 4d-примесями в ОЦК-железе

A fundamental understanding of the localization of H atoms in steel is an important step towards a theoretical description of the mechanisms of hydrogen embrittlement at the atomic level. Ab initio calculations within the framework of density functional theory (DFT) is used to investigate the effect of various substitutional impurities Mg, Al, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo , Pd and Cd on the energy of hydrogen dissolution in the lattice of bcc iron. The electronic and elastic contributions of various impurities to the dissolution energy are distinguished, and their influence on the binding energy of hydrogen and impurities is analyzed. The existence of a linear dependence of the energy of hydrogen dissolution on the magnitude of the change in the electron density of the intra-tetrahedral pore after the introduction of a hydrogen atom into it is shown. The results obtained made it possible to formulate the key mechanisms for controlling the localization of hydrogen in bcc iron by substitution impurities.

Модификация атомной и электронной структур палладия в результате растворения водорода

The results of a first-principle study of the features of changes in the atomic and electron structures of palladium as a result of hydrogen dissolution are presented. It is shown that the binding energy of hydrogen in palladium behaves irregularly: with an increase in the hydrogen concentration x = H/Pd up to 0.75, it increases and then decreases, taking negative values at hydrogen concentrations x over 1.5. It was found that, as a result of the dissolution of hydrogen in palladium, charge transfer is observed from Pd atoms to H atoms. The magnitude of this charge transfer increases as palladium becomes saturated by hydrogen.

In Situ Water Electrolyzer Stack for an Electrobioreactor

Hydrogen-oxidizing bacteria provide a sustainable solution for microbial protein production. Renewable electricity can be used for in situ water electrolysis in an electrobioreactor. The use of cultivation medium as the electrolyte enhances the hydrogen dissolution to the medium. This paper proposes a stack structure for in situ water electrolysis to improve the productivity of the electrobioreactor. The hydrogen production rate and the energy efficiency of the prototype stack are analyzed.