Phosphine-stabilised Au₉ clusters interacting with titania and silica surfaces: the first evidence for the density of states signature of the support-immobilised cluster

Gunther G Andersson; Vladimir B Golovko; Jason F Alvino; Trystan Bennett; Oliver Wrede; Sol M Mejia; Hassan S Al Qahtani; Rohul Adnan; Nathaniel Gunby; David P Anderson; Gregory F Metha

doi:10.1063/1.4884642

Phosphine-stabilised Au₉ clusters interacting with titania and silica surfaces: the first evidence for the density of states signature of the support-immobilised cluster

J Chem Phys. 2014 Jul 7;141(1):014702. doi: 10.1063/1.4884642.

Affiliations

¹ Flinders Centre for NanoScale Science and Technology, Flinders University, Adelaide SA 5001, Australia.
² Department of Chemistry, University of Adelaide, Adelaide SA 5005, Australia.
³ The MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Chemistry, University of Canterbury, Christchurch 8140, New Zealand.

PMID: 25005298
DOI: 10.1063/1.4884642

Abstract

Chemically made, atomically precise phosphine-stabilized clusters Au9(PPh3)8(NO3)3 were deposited on titania and silica from solutions at various concentrations and the samples heated under vacuum to remove the ligands. Metastable induced electron spectroscopy was used to determine the density of states at the surface, and X-ray photoelectron spectroscopy for analysing the composition of the surface. It was found for the Au9 cluster deposited on titania that the ligands react with the titania substrate. Based on analysis using the singular value decomposition algorithm, the series of MIE spectra can be described as a linear combination of 3 base spectra that are assigned to the spectra of the substrate, the phosphine ligands on the substrate, and the Au clusters anchored to titania after removal of the ligands. On silica, the Au clusters show significant agglomeration after heat treatment and no interaction of the ligands with the substrate can be identified.