Alloying effects on the reactivity of Pd are ensemble dominated

Bowker, Michael ORCID: https://orcid.org/0000-0001-5075-1089 2025. Alloying effects on the reactivity of Pd are ensemble dominated. Surface Science 751 , 122620. 10.1016/j.susc.2024.122620

Preview

PDF - Published Version Available under License Creative Commons Attribution. Download (5MB) | Preview

Abstract

In this paper the geometric (“ensemble”) and electronic (“ligand”) effects of alloying on surface reactivity and catalysis are considered. The effect of alloying on the behaviour of Pd, both in single crystal form, and as a nanoparticulate catalyst is discussed. The first case concerns Pd alloyed with Cu, and here the reactivity with formic acid and ethanol is modified by the presence of Cu. However, both Cu and Pd maintain their elemental integrity for the reactions, and it is shown that the main alloying effect is one of dilution of Pd atoms, rather than by global electronic factors such as d-band shifting and filling. Similarly, when Pd is alloyed with Au, then the adsorption characteristics (sticking probability and uptake) for CO, O2, ethene and acetaldehyde are dominated by changes in the surface arrangement of the two atoms. Au mainly acts as an adsorption blocker, but to different degrees depending upon the nature of the adsorbing molecule and its demand for particular ensemble sizes. Finally, nanoparticulate Pd is considered, and the effect of alloying on high pressure methanol synthesis from CO2 and H2 is outlined. Pd on its own is not very selective, instead it mainly produces CO and methane. However, by supporting on oxides such as ZnO, Ga2O3 and In2O3 and by reducing in hydrogen, the Pd forms alloys, which then results in high selectivity to methanol. Again, this is ascribed to the dilution of the Pd ensembles at the surface, which are the cause of methane production.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry Cardiff Catalysis Institute (CCI)
Publisher:	Elsevier
ISSN:	0039-6028
Funders:	EPSRC
Date of First Compliant Deposit:	1 November 2024
Date of Acceptance:	28 September 2024
Last Modified:	25 Nov 2024 16:23
URI:	https://orca.cardiff.ac.uk/id/eprint/173600

Actions (repository staff only)

Edit Item