Issue 9, 2014

A mechanism of gas-phase alcohol oxidation at the interface of Au nanoparticles and a MgCuCr2O4 spinel support

Abstract

The catalytic oxidation of bio-ethanol to acetaldehyde entails a promising route for valorization of biomass into many important chemicals that are currently mainly being produced from fossil-based ethylene feedstock. We employ here DFT calculations to understand the unprecedented synergy between gold clusters and a MgCuCr2O4 spinel support, which shows excellent catalytic performance for the oxidation of ethanol to acetaldehyde (space-time yield of 311 gacetaldehyde ggold−1 h−1 at 250 °C). The investigations support a mechanism involving catalytic reactions at the gold–support interface. Dissociative adsorption of ethanol is facilitated by cooperative action of a gold atom at the metal cluster–support interface and a basic oxygen atom of the support. The most difficult step is the recombinative desorption of water from the surface. The oxygen vacancy formation energy is found to be a good performance descriptor for ethanol oxidation of Au/MgMeCr2O4 (Me = Cu, Ni, Co) catalysts. The high selectivity towards acetaldehyde stems from the facile desorption of acetaldehyde as compared to the cleavage of the remaining α-C–H bond in the product. The opposite holds for methanol oxidation, explaining why experimentally we observe complete methanol oxidation over Au/MgCuCr2O4 under conditions where ethanol is selectively converted to acetaldehyde.

Graphical abstract: A mechanism of gas-phase alcohol oxidation at the interface of Au nanoparticles and a MgCuCr2O4 spinel support

Supplementary files

Article information

Article type
Paper
Submitted
11 Apr 2014
Accepted
22 May 2014
First published
23 May 2014
This article is Open Access
Creative Commons BY license

Catal. Sci. Technol., 2014,4, 2997-3003

A mechanism of gas-phase alcohol oxidation at the interface of Au nanoparticles and a MgCuCr2O4 spinel support

W. Song, P. Liu and E. J. M. Hensen, Catal. Sci. Technol., 2014, 4, 2997 DOI: 10.1039/C4CY00462K

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements