Computational investigation of α-SiO 2 surfaces as a support for Pd †

Lombard, C. J., van Sittert, C. G. C. E., Mugo, J. N., Perry, C. and Willock, David ORCID: https://orcid.org/0000-0002-8893-1090 2023. Computational investigation of α-SiO 2 surfaces as a support for Pd †. Physical Chemistry Chemical Physics 10.1039/d2cp04722e

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Abstract

The properties of a supported metal catalyst depend crucially on the interaction between the active metal and the support. A case in point is Pd supported on silica, Pd/SiO2, which is widely used in oxidation catalysis. There is a need for a broad range of computational models that describe the interaction of Pd with silica surfaces so that active site models can be proposed and tested. In this work, we create well-defined, reproducible, periodic models of SiO2 surfaces and investigate their interaction with Pd using dispersion-corrected DFT. We use crystalline α-SiO2 as a useful starting point for creating and estimating the adsorption properties of metals on SiO2 surfaces, which can represent the specific isolated functional groups present on more complex amorphous silica surfaces. We have modelled α-SiO2 (001), (100) and (101) surfaces containing isolated siloxane and silanol functional groups and estimated their affinity towards the adsorption of Pd atoms regarding an isolated gaseous Pd atom and the fcc Pd solid. This provides additional information on the ease with which Pd can be dispersed on the surfaces in question. From our model, we characterise the surface energies of the α-SiO2 (hkl) surfaces and calculate the geometries of the Pd1/α-SiO2 (hkl) adsorption site on each surface. We estimate that Pd1(g) will prefer to adsorb close to strained four-membered siloxane rings or on a vicinal silanol group of α-SiO2 (101).

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Cardiff Catalysis Institute (CCI) Chemistry
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/3.0/, Start Date: 2023-01-30
Publisher:	Royal Society of Chemistry
ISSN:	1463-9076
Funders:	EPSRC, Johnson Matthey
Date of First Compliant Deposit:	9 February 2023
Date of Acceptance:	27 January 2023
Last Modified:	04 Jul 2023 15:22
URI:	https://orca.cardiff.ac.uk/id/eprint/156599

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