Synergistic structural and surface promotion of monometallic (Pt) TWCs: Effectiveness and thermal aging tolerance

Papavasiliou, A; Tsetsekou, A; Matsouka, V; Konsolakis, M; Yentekakis, IV; Boukos, N

dc.contributor.author	Papavasiliou, A	en
dc.contributor.author	Tsetsekou, A	en
dc.contributor.author	Matsouka, V	en
dc.contributor.author	Konsolakis, M	en
dc.contributor.author	Yentekakis, IV	en
dc.contributor.author	Boukos, N	en
dc.date.accessioned	2014-03-01T01:37:12Z
dc.date.available	2014-03-01T01:37:12Z
dc.date.issued	2011	en
dc.identifier.issn	0926-3373	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/21479
dc.subject	β/β″-Al2O3	en
dc.subject	Electropositive promotion	en
dc.subject	Simulated exhaust conditions	en
dc.subject	Structural promotion	en
dc.subject	Thermal aging	en
dc.subject.classification	Chemistry, Physical	en
dc.subject.classification	Engineering, Environmental	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.other	Aging treatment	en
dc.subject.other	Automotive exhaust	en
dc.subject.other	Catalytic performance	en
dc.subject.other	Catalytic system	en
dc.subject.other	Characterization studies	en
dc.subject.other	Cordierite monolith	en
dc.subject.other	Electronic interactions	en
dc.subject.other	Electropositive promotion	en
dc.subject.other	Gain insight	en
dc.subject.other	In-situ	en
dc.subject.other	Metal contacts	en
dc.subject.other	Porosimetry	en
dc.subject.other	Pt loading	en
dc.subject.other	Scanning and transmission electron microscopy	en
dc.subject.other	Simulated exhaust conditions	en
dc.subject.other	Structural promotion	en
dc.subject.other	TGA/DTA	en
dc.subject.other	Thermal durability	en
dc.subject.other	Thermally stable	en
dc.subject.other	Washcoats	en
dc.subject.other	Cerium	en
dc.subject.other	Durability	en
dc.subject.other	Fourier transform infrared spectroscopy	en
dc.subject.other	Fourier transforms	en
dc.subject.other	Gravimetric analysis	en
dc.subject.other	Loading	en
dc.subject.other	Precious metals	en
dc.subject.other	Silicate minerals	en
dc.subject.other	Sodium	en
dc.subject.other	Spectroscopy	en
dc.subject.other	Thermal aging	en
dc.subject.other	Transmission electron microscopy	en
dc.subject.other	X ray diffraction	en
dc.subject.other	X ray diffraction analysis	en
dc.subject.other	Platinum	en
dc.title	Synergistic structural and surface promotion of monometallic (Pt) TWCs: Effectiveness and thermal aging tolerance	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.apcatb.2011.05.030	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.apcatb.2011.05.030	en
heal.language	English	en
heal.publicationDate	2011	en
heal.abstract	Highly effective and thermally stable monometallic (Pt) three way converters (TWCs) with very low Pt loading (0.5 wt%) were developed through synergistic structural and surface promotion by modifying the TWC washcoat with 20 wt% of Ce0.8La0.2O1.9 (structural promoter) and sodium in the range 5-15 wt% (surface promoter). The catalytic performance of the as prepared doubly-promoted Pt(Na)/Al2O3-(Ce0.8La0.2O1.9) catalytic systems, in both "fresh" and "aged" (at 900 degrees C) states, was studied and compared with that of a commercial bimetallic (Pt/Rh) TWC. The catalytic measurements were performed on coated cordierite monoliths, the whole concept simulating real automotive exhaust conditions at the stoichiometric point. An extensive characterization study, involving thermo-gravimetric analysis (TGA/DTA), scanning and transmission electron microscopy (SEM, TEM), X-ray diffraction (XRD), N-2 porosimetry and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), was undertaken in order to gain insight and correlate the structural/textural characteristics of these novel catalytic systems with their performance and substantial thermal aging tolerance. Optimum behavior in terms of both catalytic efficacy in simulated TWC conditions and thermal durability, even in comparison with the commercial bimetallic TWC with similar to 4.5-fold higher precious metal loading, was demonstrated by the doubly promoted Pt(Na)/Al2O3-(Ce0.8La0.2O1.9) sample with the higher sodium loading of 15 wt% Na. The formation of beta ''-alumina during aging treatment, providing intimate alkali-noble metal contact and therefore preserving their electronic interactions, suggests the mechanism for the enhanced thermal durability and the origin of the remained after aging alkali action. (C) 2011 Elsevier B.V. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Applied Catalysis B: Environmental	en
dc.identifier.doi	10.1016/j.apcatb.2011.05.030	en
dc.identifier.isi	ISI:000293105100027	en
dc.identifier.volume	106	en
dc.identifier.issue	1-2	en
dc.identifier.spage	228	en
dc.identifier.epage	241	en