In:
Catalysis Science & Technology, Royal Society of Chemistry (RSC), Vol. 12, No. 11 ( 2022), p. 3534-3548
Abstract:
The cost of Pt is currently lower than that of Pd and Rh, however, Pt-based three-way catalysts (TWCs) have attracted less attention than Pd- and Rh-based TWCs. Consequently, the fundamental understanding of the properties of Pt-based TWCs remains insufficient. Herein, we demonstrate the effect of oxygen storage materials (OSMs), including CeO 2 and CeO 2 –ZrO 2 solid-solutions having different ceria contents (20%, 45%, and 66%), on the three-way catalysis performance of Pt/OSMs using various spectroscopic observations in combination with kinetic studies. In comparative assessments of powdered and monolithic (honeycomb) catalysts, fresh Pt/OSM(100%CeO 2 ) and aged Pt/OSM(66%CeO 2 ) exhibited the highest NO conversion among their corresponding series, showing that Pt/OSM(66%CeO 2 ) is the most promising and stable among the TWCs. In situ CO adsorption infrared (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) revealed that the Pt 0 species loaded on OSMs having a higher ceria content were more electron-deficient. Operando IR and kinetic investigations suggested that increasing the ceria content in fresh Pt/OSMs enhanced not only the formation of nitrite species and their reactivity toward CO but also the resistance to CO poisoning during NO–CO reactions. In situ X-ray absorption spectroscopy (XAS) indicated that both Ce and Pt species in Pt/OSM catalysts are involved in NO–CO reactions through their redox cycles. In situ XAS in combination with X-ray diffraction (XRD) measurements revealed that the hydrothermal ageing treatment resulted in the aggregation of Pt particles and lattice contraction of CeO 2 in Pt/OSMs, causing severe degradation of the redox ability of Pt and Ce species and reducing the promoting effect of ceria on the formation of nitrites and their reactivity toward CO.
Type of Medium:
Online Resource
ISSN:
2044-4753
,
2044-4761
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2022
detail.hit.zdb_id:
2595090-3
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