Molecular hydrogen interactions with discontinuous and continuous thin gold films

Abstract

The influence of thin gold film surface nanostructure on H 2 chemisorption on unsintered gold films at 78 K was studied. Three classes of thin Au films of different thicknesses were chosen for these experiments, as follows: (i) very thin, purplish colour, transparent film formed by isolated Au islands, (ii) violet–green colour film formed by Au islands joined together and creating a kind of golden net, (iii) non-transparent, continuous Au film of golden colour. It has been found that H 2 chemisorption occurs only in the case when the thin Au films are deposited at low temperatures (78 K) and unsintered. It has been suggested that this chemisorption occurs on surface Au atoms of low coordination number as a result of formation of AuH 2 complexes, similarly to the compounds arising due to H 2 interaction with isolated Au atoms.