Ni Nanostructures in Porous Anodic Alumina Matrices: Structure and Cathodic Properties in Hydrogen Release Reactions

A synthesis has been performed of Ni nanostructures by magnetron deposition on the matrices of porous alumina obtained by the two-stage anodic oxidation. The scanning electron microscopy method is used to investigate alumina films before and after nickel deposition. Investigations by X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy and EXAFS show that the nickel deposited on porous alumina is in an oxidized state, in contrast to nickel deposited on a substrate with a smooth surface. No influence of the porous structure of matrices on the structure of nickel and the composition of near-surface layers has been detected. The catalytic properties of the nanostructures in hydrogen release reactions in a 5 M NaOH solution are analyzed. It is shown that the nickel films deposited on porous alumina exhibit a greater catalytic activity in hydrogen release reactions than the nickel film deposited on a smooth aluminum substrate.