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Deactivation of a single-site gold-on-carbon acetylene hydrochlorination catalyst: An X-ray absorption and inelastic neutron scattering study - data

Deactivation of a single-site gold-on-carbon acetylene hydrochlorination catalyst: An X-ray absorption and inelastic neutron scattering study - data
Deactivation of a single-site gold-on-carbon acetylene hydrochlorination catalyst: An X-ray absorption and inelastic neutron scattering study - data
Data comprises XAFS and Mass spectrometry measurements for various chemical species. Single-site Au species supported on carbon have been shown to be the active sites for acetylene hydrochlorination. The evolution of these single-site species has been monitored by Au L3 X-ray absorption spectroscopy (XAS). Alternating between a standard reaction mixture of HCl/C2H2 and the single reactants has provided insights into the reaction mechanism and catalyst deactivation processes. We demonstrate that oxidative addition of HCl across an Au(I) chloride species requires concerted addition with C2H2, in accordance with both the XAS measurements of Au oxidation state and the reaction kinetics being first order with respect to each reactant. Excess C2H2 changes the Au speciation and results in the formation of oligomeric acetylene species which were detected by inelastic neutron scattering. Catalyst deactivation at extended reaction times can be correlated with the formation of metallic Au particles. These Au(0) species generated during the sequential gas experiments, or after prolonged reaction times, results in the analysis of the normalized near-edge white line intensity becoming an unsuitable guide for identifying the active Au species, affecting the strong correlation between normalized white line height and VCM productivity usually observed in the active catalyst. Thus, a combination of scanning transmission electron microscopy and detailed modeling of whole XAS spectrum was required to distinguish active Au(I) and Au(III) species from the spectator Au(0) component.
Cardiff University
Malta, Grazia
f8644878-b7a5-4e78-b099-8ea07b1dd233
Freakley, Simon J
4d006e28-df91-4fdf-b820-a6377ee38741
Kondrat, Simon A
8f09c877-8bb6-4c82-8f81-564085479aff
Gibson, Emma K.
36a66f7f-2aa4-4c04-9f4d-5925017a99a1
Wells, Peter P
bc4fdc2d-a490-41bf-86cc-400edecf2266
Malta, Grazia
f8644878-b7a5-4e78-b099-8ea07b1dd233
Freakley, Simon J
4d006e28-df91-4fdf-b820-a6377ee38741
Kondrat, Simon A
8f09c877-8bb6-4c82-8f81-564085479aff
Gibson, Emma K.
36a66f7f-2aa4-4c04-9f4d-5925017a99a1
Wells, Peter P
bc4fdc2d-a490-41bf-86cc-400edecf2266

Malta, Grazia and Gibson, Emma K. (2020) Deactivation of a single-site gold-on-carbon acetylene hydrochlorination catalyst: An X-ray absorption and inelastic neutron scattering study - data. Cardiff University doi:10.17035/d.2018.0054961412 [Dataset]

Record type: Dataset

Abstract

Data comprises XAFS and Mass spectrometry measurements for various chemical species. Single-site Au species supported on carbon have been shown to be the active sites for acetylene hydrochlorination. The evolution of these single-site species has been monitored by Au L3 X-ray absorption spectroscopy (XAS). Alternating between a standard reaction mixture of HCl/C2H2 and the single reactants has provided insights into the reaction mechanism and catalyst deactivation processes. We demonstrate that oxidative addition of HCl across an Au(I) chloride species requires concerted addition with C2H2, in accordance with both the XAS measurements of Au oxidation state and the reaction kinetics being first order with respect to each reactant. Excess C2H2 changes the Au speciation and results in the formation of oligomeric acetylene species which were detected by inelastic neutron scattering. Catalyst deactivation at extended reaction times can be correlated with the formation of metallic Au particles. These Au(0) species generated during the sequential gas experiments, or after prolonged reaction times, results in the analysis of the normalized near-edge white line intensity becoming an unsuitable guide for identifying the active Au species, affecting the strong correlation between normalized white line height and VCM productivity usually observed in the active catalyst. Thus, a combination of scanning transmission electron microscopy and detailed modeling of whole XAS spectrum was required to distinguish active Au(I) and Au(III) species from the spectator Au(0) component.

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More information

Published date: 1 January 2020

Identifiers

Local EPrints ID: 448913
URI: http://eprints.soton.ac.uk/id/eprint/448913
PURE UUID: ad2f292b-029d-47e4-b2f1-603903cf3817
ORCID for Peter P Wells: ORCID iD orcid.org/0000-0002-0859-9172

Catalogue record

Date deposited: 10 May 2021 16:33
Last modified: 15 Dec 2021 02:38

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Contributors

Creator: Grazia Malta
Contributor: Simon J Freakley
Contributor: Simon A Kondrat
Creator: Emma K. Gibson
Contributor: Peter P Wells ORCID iD

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