Issue 8, 2023

Computational investigation of α-SiO2 surfaces as a support for Pd

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).

Graphical abstract: Computational investigation of α-SiO2 surfaces as a support for Pd

Supplementary files

Article information

Article type
Paper
Submitted
10 okt 2022
Accepted
27 jan 2023
First published
30 jan 2023
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2023,25, 6121-6130

Computational investigation of α-SiO2 surfaces as a support for Pd

C. J. Lombard, C. G. C. E. van Sittert, J. N. Mugo, C. Perry and D. J. Willock, Phys. Chem. Chem. Phys., 2023, 25, 6121 DOI: 10.1039/D2CP04722E

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