Unusual behaviour of Au/ZnO catalysts in selective hydrogenation of butadiene due to the formation of a AuZn nanoalloy

Abstract

The loss of activity observed when Au/ZnO was activated under H2 was explained by the formation of AuZn alloy.

Pd–Au bimetallic catalysts supported on ZnO for selective 1,3-butadiene hydrogenation

“…inhibition of hydrogenation, are consistent with the decrease in the number of low coordinated gold sites due to the formation of Au1Zn1 nanoalloy after reduction, as has been reported previously. 23 The slightly better performance of the sample supported on ZnO-t may suggest a particular metal-support interaction. It has been suggested that this interaction favoured the presence of epitaxially-grown Au nanoparticles on tetrapod supports compared to other ZnO supports, which explains, for example, the higher activities of those catalysts in CO oxidation.…”

“…57 In addition, this electronic effect is claimed to depend on the surface, being more pronounced for dense PdAu(111) surfaces. (42) 100 (25) 100 (48) PdAu-ZnO-t 6 60 (54) 99 (32) 98 (42) Pd-ZnO-n 4 86 (55) 97 (60) 97 (80) PdAu-ZnO-n 3 59 (48) 92 (23) 100 (48) Catalysis Science & Technology Paper…”

“…22 Depending on the thermal treatments and gas atmospheres, the formation of αand/or β-PdZn and AuZn alloys and intermetallic structures, as well as the presence of strong-metal support interaction (SMSI) states, have been reported. [16][17][18][23][24][25][26] Zn incorporation seems to change the number of ensemble active atoms as well as the Pd or Au electronic properties due to charge transfer between Zn and the metal, consequently affecting the catalytic behaviour. In addition, the catalytic performance of PdZn and AuZn phases seem to be influenced by the exposed ZnO facets.…”

Highly Selective Au/ZnO via Colloidal Deposition for CO2 Hydrogenation to Methanol: Evidence of AuZn Role

“…Following reduction at 400 °C, the peak associated to Au(111) crystalline plane showed an increase in intensity with a sharp peak appeared at 38.8°. A small peak appeared at 39.6° which indicates the formation of AuZn alloy [16,17]. Re- duction of Au/ZnO at 400 °C reduced the ZnO within Au perimeter via hydrogen atom spill over.…”

A Brief Review of the Synthesis and Catalytic Applications of Graphene‐Coated Oxides

“…However, some oxide supports, especially easily reducible oxides notably TiO 2 or ZnO, may also cause the deactivation of the catalyst under certain conditions. This can take place through strong interactions with metals, for example, by encapsulation of the active centers or oxidation of the metals and formation of inert mixed‐oxide compounds . Recently the idea to cover oxides with carbon in order to improve their stability, and consequently their performance, has attracted a lot of attention.…”