Can be metal layered hydroxide an alternative for hydride production by cold H2/Ar plasma treatment?

Abstract

Layered nickel hydroxide ß-Ni(OH)2 was produced by aqueous precipitation and subsequently exposed to a cold H2/Ar (90/10) plasma, to tentatively reduce nickel hydroxide into nickel hydride by plasma hydrogen ion species interaction/implantation. Due to its open structure nickel hydroxide was expected to be extremely sensitive and reactive toward plasma exposure. Unfortunately, X-ray diffraction and Transmission electron microscopy coupled to hydrogen quantification by thermodesorption evidenced a completely different scenario. Even if nickel nanoparticles were rapidly formed (in 2 h under plasma exposure) the irradiation created atomic displacements and induced significant microstructural alteration, with the generation of large concentrations of defects, including grain boundaries, dislocations, twinnings, and others. As a consequence, hydrogen atoms were irreversibly trapped in those sites and accounts for about 1000 ppm, while for the desired Ni2H or NiH hydrides the expected hydrogen content should be 8513 and 16,881 ppm, respectively.