Hydrogenation by gold catalysts: an unexpected discovery and a current assessment

• Published in: Gold bulletin (World Gold Council) Vol. 49; no. 3-4; pp. 53 - 61
• Main Author: Bond, Geoffrey C.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.12.2016; Springer Nature B.V
• Subjects: Aluminum oxide; Balancing; Catalysis; Catalysts; Chemisorption; Chemistry and Materials Science; Gold; Hydrogenation; Materials Science; Metallic Materials; Olefins; Original Paper; Nanoparticles; H; chemisorption; Non-metallic character; Au; Hydrogenation
• ISSN: 2364-821X; 2190-7579
• DOI: 10.1007/s13404-016-0182-8

Gold in the massive state shows little tendency either to chemisorb simple molecules or to act catalytically. The discovery made in 1973 that low loadings of Au on Al 2 O 3 and particularly on SiO 2 were active in alkene hydrogenation when prepared by thermal decomposition of adsorbed AuCl 4 − paved the way for later extensive studies of catalysis by this metal. The activity was attributed to that being Au particles <4 nm in size, and it soon appeared that similar catalysts performed the selective hydrogenation of 2-butyne and 1,3-butadiene. Later work strongly suggests that Au particles below ∼2.5 nm in size, and having non-metallic character, are especially adept at H 2 chemisorption and H 2 -D 2 equilibration, and that alkene hydrogenation then occurs in an H-rich environment. Larger Au particles have more limited activity, perhaps associated with atoms of low coordination number and an H-poor environment.