Stabilization of catalyst particles against sintering on oxide supports with high oxygen ion lability exemplified by Ir-catalyzed decomposition of N2OStabilization of catalyst particles against sintering on oxide supports with high oxygen ion lability exemplified by Ir-catalyzed decomposition of N2O Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2018-10-042016enIridium nanoparticles deposited on a variety of surfaces exhibited thermal sintering characteristics that were very strongly correlated with the lability of lattice oxygen in the supporting oxide materials. Specifically, the higher the lability of oxygen ions in the support, the greater the resistance of the nanoparticles to sintering in an oxidative environment. Thus with γ-Al2O3 as the support, rapid and extensive sintering occurred. In striking contrast, when supported on gadolinia-ceria and alumina-ceria-zirconia composite, the Ir nanoparticles underwent negligible sintering. In keeping with this trend, the behavior found with yttria-stabilized zirconia was an intermediate between the two extremes. This resistance, or lack of resistance, to sintering is considered in terms of oxygen spillover from support to nanoparticles and discussed with respect to the alternative mechanisms of Ostwald ripening versus nanoparticle diffusion. Activity towards the decomposition of N2O, a reaction that displays pronounced sensitivity to catalyst particle size (large particles more active than small particles), was used to confirm that catalytic behavior was consistent with the independently measured sintering characteristics. It was found that the nanoparticle active phase was Ir oxide, which is metallic, possibly present as a capping layer. Moreover, observed turnover frequencies indicated that catalyst-support interactions were important in the cases of the sinter-resistant systems, an effect that may itself be linked to the phenomena that gave rise to materials with a strong resistance to nanoparticle sintering.http://creativecommons.org/licenses/by/4.0/Applied Catalysis B: Environmental192357-364Yentekakis_et_al_Appl. Catal B-Environ._192_2016.pdfChania [Greece]Library of TUC2018-10-04application/pdf2.2 MBfree Gentekakis Ioannis Γεντεκακης Ιωαννης Goula Grammatiki Γουλα Γραμματικη Panagiotopoulou Paraskevi Παναγιωτοπουλου Παρασκευη Kabouri Stavroula Καμπουρη Σταυρουλα Taylor Martin J. Kyriakou George Lambert Richard M. Elsevier Alumina Catalytic N2O decomposition Ceria Gadolinia Iridium Iridium oxide Nanoparticle stabilization Ostwald ripening Oxide supports Oxygen ion lability Particle diffusion Sintering Zirconia