Identification of single-site gold catalysis in acetylene hydrochlorination
journal contributionposted on 30.05.2018, 13:27 authored by Grazia Malta, Simon KondratSimon Kondrat, Simon J. Freakley, Catherine J. Davies, Li Lu, Simon R. Dawson, Adam Thetford, Emma K. Gibson, David J. Morgan, Wilm Jones, Peter P. Wells, Peter Johnston, C. Richard A. Catlow, Christopher J. Kiely, Graham J. Hutchings
There remains considerable debate over the active form of gold under operating conditions of a recently validated gold catalyst for acetylene hydrochlorination.We have performed an in situ x-ray absorption fine structure study of gold/carbon (Au/C) catalysts under acetylene hydrochlorination reaction conditions and show that highly active catalysts comprise single-site cationic Au entities whose activity correlates with the ratio of Au(I):Au(III) present. We demonstrate that these Au/C catalysts are supported analogs of single-site homogeneous Au catalysts and propose a mechanism, supported by computational modeling, based on a redox couple of Au(I)-Au(III) species.
We acknowledge Cardiff University for support as part of the MAXNET Energy Consortium. We also thank R. Schloegl for helpful discussions. UK Catalysis Hub is thanked for resources and support provided through our membership of the UK Catalysis Hub Consortium and funded by the Engineering and Physical Sciences Research Council (EPSRC) (grants EP/K014706/1, EP/K014668/1, EP/K014854/1EP/K014714/1, and EP/M013219/1). We used the B18 beamline at the Diamond Light Source (allocation numbers SP10306, SP11398, and SP15214) with the help of D. Gianolio and G. Cibin. C.J.K. acknowledges funding from the National Science Foundation Major Research Instrumentation program (GR no. MRI/DMR-1040229). We thank Johnson Matthey for their contribution to and funding of this work. Calculations were performed through our membership of the UK’s High-End Computing (HEC) Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202); this work used the Advanced Research Computing High-End Resource (ARCHER) UK National Supercomputing Service (www.archer.ac.uk). Local high performance computing (HPC) services at University College London (UCL) were used on the Grace computer.