Electrocatalytic activity for the hydrogen evolution reaction on Ni–Co–LaNi5 composite electrodes prepared by electrochemical codeposition technique was evaluated. The relationship between the current density for hydrogen evolution reaction and the amount of LaNi5 particles in Ni–Co baths is like the well-known “volcano plot”. The Surface morphology and microstructure of Ni–Co–LaNi5 coatings we...

Complete hydrogen isotherms have been measured using highly stoichiometric, activated LaNi5 over a wide temperature range, 373 K to 228 K. Van’t Hoff plots for hydride formation and decomposition have been constructed using the isotherms in the low temperature range from 228 K to 298 K. The following thermodynamic results have been obtained from these plots: IAHP1., I = 15.4 kJ/ mol ~H2 and lAS...

The study focuses on the reaction between hydrogen gas and LaNi5 xSnx alloys, where 0 x 0.5, in broad temperature and pressure ranges. It was performed by means of dynamic volumetric techniques using specific equipment developed at our laboratory. The substitution of Ni by Sn lowers the system equilibrium pressure and increases the hydrogen absorption reaction rate. Reaction pressures at room t...

This paper reports the effect of high-pressure torsion (HPT) on first hydrogenation LaNi5. We found that, for loose powder, reduction particle size has an increasing incubation time and decreasing hydrogen capacity. A higher amount HPT turns only marginally reduce but no In all cases, dehydrogenation subsequent have same kinetics, irrespective or number turns. Therefore, LaNi5, a beneficial hyd...

هیدریدهای فلزی به دلیل واکنش گرمازا و گرماگیر با هیدروژن می­توانند به منظور سرمایش و یا گرمایش محیط مورد استفاده قرار گیرند. در این تحقیق توانایی سردسازی پمپ­های گرمایی بر پایه هیدریدهای فلزی دارای کمپرسور (cdmhhp) برای اولین بار با استفاده از یک مدل دو بعدی مورد بررسی قرار گرفته است. تحقیقات گذشته بر روی cdmhhp ها تنها با استفاده از مدل یک بعدی صورت گرفته است. نتایج حاصل از شبیه­سازی با نتایج ...

Mossbauer spectroscopy has been used to study both the physics and phenomenology of hydrogen absorption in rare-earth intermetallics. This paper surveys experiments that have been carried out so far, and discusses the results obtained. * * * * * * * * LaNi5 and similar intermetallic compounds have been of great interest recentlyl because of their ability to absorb reversibly large amounts of hy...

Energy-filtered transmission electron microscopy (EFTEM) can be used to acquire elemental distribution maps at high lateral resolution within short acquisition times, which makes it quite efficient for a detailed characterization of nanostructures, as illustrated with examples concerning a nanostructured substituted La-based cermet compound and a nanoscale multilayer. In the first example, we s...

The acoustic emission technique is proposed for assessing the irreversible phenomena occurring during hydrogen absorption/desorption cycling in LaNi5. In particular, we have studied, through a parametric analysis of in situ detected signals, the correlation between acoustic emission (AE) parameters and the processes occurring during the activation of an intermetallic compound. Decreases in the ...