Size-dependent selectivity and activity of silver nanoclusters in the partial oxidation of propylene to propylene oxide and acrolein: A joint experimental and theoretical study
Academic Article
Publication Date:
2011
abstract:
Model silvernanocatalystsbetween9and23nminsizewerepreparedbysize-selectedclusterdeposition
from afreeclusterbeamonamorphousaluminafilmsandtheirsize-dependentcatalyticperformance
studied inthepartialoxidationofpropyleneunderrealisticreactionconditions.Smallerclusterspref-
erentially producedacrolein,whilethe23nmparticleswereconsiderablymoreselectivetowardsthe
formation ofpropyleneoxide,atreactionratesfarexceedingthosepreviouslyreportedforlargersilver
particles. Theactivityofclustersdroppedsignificantlywithincreasingparticlesize.First-principlecalcu-
lations, oftheactivationenergiesforoxygenadsorptionanditsdissociation,atvariablesurfacecoverage
yielded surfaceenergieswhichresultedinparticleshapesresemblingtheexperimentallyobservedshapes
of partiallyoxidizedsilverclusters.Thecalculatedactivationbarriersforpropyleneoxideandacrolein
formation onvariousfacetsandontheedgesofthenanoparticlesprovideddetailedinformationabout
the energeticsofthecompetingreactionpathways.Thesize-andcorrespondingmorphology dependent
theoretical activityandselectivity are in good accord with experimental observations.
Iris type:
01.01 Articolo in rivista
List of contributors:
Fortunelli, Alessandro; Barcaro, Giovanni
Published in: