ThehighlydispersedPt–ReOX(x≤1)sitesca.0.5nminsizewereformedviaasuccessiveandstronginteractionoftheReprecursorwithtitaniaandthenofthePtcomplexwithdepositedlow-valentrheniumoxideclusters.Thesize,chargeandchemicalcompositionwerecharacterizedbymeansofHRTEM/STEMwithEDXmapping,XPS,andFTIRS.ThesesiteswithRe/Pt=2wereshowntobehighlyactiveandselectiveinthehydrogenationofcarboxylicacidtoalcoholunderverymildconditions(T=130°C,P=50bar).ThereactionrateconstantforthehydrogenationofhexanoicacidincreasedlinearlywiththePtcontent.Asforthehomogeneouspincer-typeRu-organiccomplexes,theactivePt–ReOXsitescandissociateheterolyticallythemolecularhydrogenwiththeformationofhydroxylgroupsandPthydrideforhydrogenationofthecarboxylicgroup.Indeed,TOFof20h-1andselectivityof98%–99%areapproachingthevaluestypicalofhomogeneouscatalysts.Thefirstorderkineticsdescribedwelltheexperimentaldataobtainedinawiderangeofreactionconditions.
