TY - JOUR AU - Litvinov, V.A. AU - Okseniuk, I.I. AU - Shevchenko, D.I. AU - Bobkov, V.V. PY - 2021/09/13 Y2 - 2024/03/29 TI - Secondary-Ion Mass Spectrometry Study of LaNi5-Hydrogen-Oxygen System JF - Ukrainian Journal of Physics JA - Ukr. J. Phys. VL - 66 IS - 8 SE - Surface physics DO - 10.15407/ujpe66.8.723 UR - https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2020257 SP - 723 AB - <p>The results obtained while studying the surface of the LaNi<sub>5</sub> alloy using secondary ion mass spectrometry are reported. It has been shown that the simultaneous action of hydrogen and oxygen on the alloy surface leads to the formation of a complex chemical surface structure consisting of hydrides, hydroxides, and oxides of lanthanum and nickel. The stoichiometric ratios of elements in those compounds depend on the hydrogen and oxygen fractions in the gas mixture. Oxygen interaction with the alloy surface stimulates the surface segregation and grouping of nickel atoms into large clusters. Until there remain sites free from oxides and hydroxides on the surface of such nickel clusters, they serve as catalytically active centers for dissociative chemisorption of hydrogen molecules, thus promoting hydrogenation processes.</p> ER -