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Homocoupling of phenylboronic acid using atomically dispersed gold on carbon catalysts: catalyst evolution before reaction

DOI: 10.1002/cctc.201701840 DOI Help

Authors: Tanja E. Parmentier (Cardiff Catalysis Institute, Cardiff University) , Simon R. Dawson (Cardiff Catalysis Institute, Cardiff University) , Grazia Malta (Cardiff Catalysis Institute, Cardiff University) , Li Lu (Lehigh University) , Thomas E. Davies (Cardiff Catalysis Institute, Cardiff University) , Simon A. Kondrat (Cardiff Catalysis Institute, Cardiff University) , Simon J. Freakley (Cardiff Catalysis Institute, Cardiff University) , Christopher J. Kiely (Cardiff Catalysis Institute, Cardiff University; Lehigh University) , Graham J. Hutchings (Cardiff Catalysis Institute, Cardiff University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemcatchem

State: Published (Approved)
Published: December 2017
Diamond Proposal Number(s): 15151

Abstract: Coupling reactions to form new C-C bonds are extensively used in industrial synthetic processes. Gold has been shown to be an active catalyst for such reactions however, conflicting reports exist as to whether cationic Au or metallic Au is acting as the active species. We prepared a heterogeneous catalyst consisting of atomically dispersed Au-Clx supported on carbon and showed this to be active in the homocoupling of phenylboronic acid to biphenyl. However; characterisation of the catalyst materials, even after just a short exposure time to the reactants, revealed rapid reduction and sintering of the Au species into larger metallic nanoparticles which we propose to be the true active species in this instance. This study suggests that if cationic Au is an active catalyst, it must be stabilised against reduction and agglomeration by either forming complexes which are more stable than common chlorides or by strongly anchoring them firmly onto alternative support materials; as in this case the carbon supported Au-Cl species were easily reduced.

Journal Keywords: Gold; Single Site Catalyst

Subject Areas: Chemistry

Instruments: B18-Core EXAFS

Added On: 24/01/2018 08:29

Discipline Tags:

Physical Chemistry Catalysis Chemistry

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) Extended X-ray Absorption Fine Structure (EXAFS)