Structure-reactivity correlations in Pd-Au bimetallic nanoclusters

Elad Gross, Micha Asscher*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The effect of composition and morphology of bimetallic Pd-Au nanoclusters on their chemical reactivity has been studied with acetylene decomposition and conversion to ethylene and benzene as the chemical probe. High resolution transmission electron microscopy (HR-TEM) and CO-Temperature Programmed Desorption (TPD) measurements were employed for structure and chemical composition determination. Pd-Au clusters were prepared in ultrahigh vacuum (UHV) environment on SiO2/Si(100) by direct deposition (DD) to form 2D bimetallic nanostructures. Different bimetallic cluster morphology could be obtained by employing the buffer layer assisted growth (BLAG) procedure with amorphous solid water as buffer material. The BLAG bimetallic clusters were found to be more reactive than DD particles toward acetylene hydrogenation to ethylene and trimerization to benzene. The morphology and composition of DD clusters enabled the formation of both tilted (low adsorption energy) and flat laying (high adsorption energy) benzene, while mainly tilted benzene was detected upon adsorption of acetylene on BLAG clusters. Moreover, the reactivity of bimetallic clusters was compared to that of thin Pd film. Strong preference (100:1 ratio) toward acetylene hydrogenation to ethylene over trimerization to benzene has been correlated with the lack of extended Pd(111) facets on the bimetallic clusters that suppress the benzene formation.

Original languageAmerican English
Pages (from-to)16226-16231
Number of pages6
JournalLangmuir
Volume26
Issue number21
DOIs
StatePublished - 2 Nov 2010

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