Cathodic hydrogen charging as a tool to activate Cu–Ti amorphous alloy catalysts

Abstract

Degradation processes occurring at the surface and in the bulk of Cu-based amorphous alloys during cathodic hydrogen charging were used for enhancing their catalytic activity. Thus, the degradation processes caused by hydrogen charging (modifying the structure, composition and morphology of the substrate) proved to be useful methods of transforming Cu–Ti amorphous alloy precursors into active and stable catalysts. Hydrogen charging was applied to Cu60–Ti40 amorphous ribbons in an acid solution (0.1 M H 2SO 4) in order to bring about pronounced morphological and structural changes. The samples were then catalytically tested for dehydrogenation of 2-propanol. Catalytic activity increased up to a conversion level of ∼60% at selectivities to acetone of about 99%. The chemical and morphological changes were followed by SEM (Hitachi 3500N) and Auger electron microanalysis (Microlab 350). Porosity and specific surface area were measured (ASAP 2010 Sorptometer), and hydrogen content was determined by elemental analysis. The rather low average specific surface area and porosity, as well as a lack of Cu 0 both before and after the catalytic test suggest that the generally accepted mechanism for the dehydrogenation of alcohols over copper catalysts with the involvement of Cu 0 is not operative here.