CeO2 promoted Ag/TiO2 catalyst for soot oxidation with improved active oxygen generation and delivery abilities

Kim, Min June; Han, Geun-Ho; Lee, Seong Ho; Jung, Hyun Wook; Choung, Jin Woo; Kim, Chang Hwan; Lee, Kwan Young

doi:10.1016/j.jhazmat.2019.121341

Cited by 36 publications

(15 citation statements)

References 45 publications

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“…Kim et al [48] investigated Ag-based catalysts focusing on the effect of support. For this purpose, they compared the soot oxidation activities of Ag/CeO 2 with that of samples prepared by impregnating the same amount of Ag (5 wt.%) on different types of TiO 2 (i.e., pure anatase, pure rutile, and P25, which contains both anatase and rutile phases).…”

Section: Metal-loaded Ceria-based Catalystsmentioning

confidence: 99%

Catalytic Materials for Gasoline Particulate Filters Soot Oxidation

Matarrese

2021

Catalysts

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The energy efficiency of Gasoline Direct Injection (GDI) engines is leading to a continuous increase in GDI engine vehicle population. Consequently, their particulate matter (soot) emissions are also becoming a matter of concern. As required for diesel engines, to meet the limits set by regulations, catalyzed particulate filters are considered as an effective solution through which soot could be trapped and burnt out. However, in contrast to diesel application, the regeneration of gasoline particulate filters (GPF) is critical, as it occurs with almost an absence of NOx and under oxygen deficiency. Therefore, in the recent years it was of scientific interest to develop efficient soot oxidation catalysts that fit such particular gasoline operating conditions. Among them ceria- and perovskite-based formulations are emerging as the most promising materials. This overview summarizes the very recent academic contributions focusing on soot oxidation materials for GDI, in order to point out the most promising directions in this research area.

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Section: Metal-loaded Ceria-based Catalystsmentioning

confidence: 99%

Catalytic Materials for Gasoline Particulate Filters Soot Oxidation

Matarrese

2021

Catalysts

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“…Moreover, it showed very active catalysts in a fresh or aged state [12]. The titanium oxide, which used with silver catalyst, showed high oxidation efficiency of soot in the tight contact between catalyst and soot [16]. From, several works of literature caused interest in the oxide materials to use with silver metal such as Al2O3, TiO2, and ZrO2.…”

Section: Introductionmentioning

confidence: 99%

Soot Oxidation in Diesel Exhaust on Silver Catalyst Supported by Alumina, Titanium and Zirconium

Promhuad

Sawatmongkhon

2021

E3S Web Conf.

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Diesel Particulate Filter (DPF) is used to limit the emission of particulate matter (PM). The operation of DPF has two consecutive functions which are filtration of PM and regeneration. Performance of DPF is reduced by clogging of the filter. This problem is improved by soot oxidation in the regeneration process. The soot is completely oxidized by oxygen when temperature is higher than 600 °C. However, the exhaust gas temperature in normal operating of the diesel engine is lower than the temperature of soot complete oxidation. The problem of low temperature in soot oxidation is improved by oxidation catalyst because the oxidation catalyst is used to reduce light of temperature in soot oxidation. The study’s purpose is to compare the oxidation activity of silver catalyst supported on alumina (Al2O3), Titanium oxide (TiO2), and Zirconium oxide (ZrO2). The compression of soot oxidation on silver catalyst loaded on several support which showed silver base on alumina was the best of soot oxidation compared with titanium oxide and zirconium oxide. The behaviour of soot oxidation in silver base on titanium oxide and zirconium oxide were similar activity.

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“…5,14,15 Among the reducible oxides, ceria (CeO 2 ) and titania (TiO 2 ) have been the most investigated ones in catalysis. 16 Although Ag/CeO 2 composites are known to be highly active for a huge number of catalytic reactions, 4,5,7,8,10,11,17,18 the Ag/TiO 2 composites have shown promising oxidant activity only recently. 4 Two mechanisms have been proposed to explain the oxidation activity of these systems: one involves the release of O from the oxide lattice (Mars-van Kravelen, MvK) and the other involves the production of oxygenated species as peroxide (O (Langmuir−Hinshelwood mechanism, LH) or the gas-phase substrate (Eley−Rideal mechanism, ER).…”

Section: Introductionmentioning

confidence: 99%

“…16 Although Ag/CeO 2 composites are known to be highly active for a huge number of catalytic reactions, 4,5,7,8,10,11,17,18 the Ag/TiO 2 composites have shown promising oxidant activity only recently. 4 Two mechanisms have been proposed to explain the oxidation activity of these systems: one involves the release of O from the oxide lattice (Mars-van Kravelen, MvK) and the other involves the production of oxygenated species as peroxide (O (Langmuir−Hinshelwood mechanism, LH) or the gas-phase substrate (Eley−Rideal mechanism, ER). 19,20 The MvK mechanism involves the formation of an oxygen vacancy (V O ) at the oxide surface MO 2 (CeO 2 /TiO 2 ), with the reduction of a couple of M 4+ (Ce 4+ /Ti 4+ ) cations to M 3+ (Ce 3+ / Ti 3+ ) for each neutral V O formed.…”

Section: Introductionmentioning

confidence: 99%

“…Transition-metal nanoparticles (NPs) dispersed over metal-oxide supports constitute one of the main types of heterogeneous catalysts, with countless applications in many industrial and technological processes for the abatement of environmental pollutants produced by industrial activity and motor vehicles. − In particular, catalysts based on silver NPs supported at the oxide surfaces are appealing for their high activity in low-temperature oxidation processes − and their remarkable lower costs with respect to those based on gold and platinum, making them more suitable for large-scale applications. , It is known that the catalytic activity toward the oxidation of silver NPs supported on reducible oxides is enhanced by the metal-support interaction effects which boost the reactivity of both the support and metal. ,, Among the reducible oxides, ceria (CeO 2 ) and titania (TiO 2 ) have been the most investigated ones in catalysis . Although Ag/CeO 2 composites are known to be highly active for a huge number of catalytic reactions, ,,,,,,, the Ag/TiO 2 composites have shown promising oxidant activity only recently …”

Section: Introductionmentioning

confidence: 99%

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O₂ Activation over Ag-Decorated CeO₂(111) and TiO₂(110) Surfaces: A Theoretical Comparative Investigation

et al. 2020

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Periodic spin-polarized hybrid density functional theory calculations have been performed to investigate the reactivity of pristine, O-defective, and Ag-decorated CeO 2 (111) and TiO 2 (110) surfaces with a small Ag 10 cluster toward O 2 . The adsorption of O 2 and its subsequent dissociation have been studied in order to provide a better understanding of the role of the oxide, the metallic nanoparticle, and their interaction in the reactivity of composite metal/metal oxide materials toward O 2 , as potential catalysts to this reaction. Structural, energetic, electronic, and vibrational properties of all species involved in the different reaction paths considered have been fully characterized. On the stoichiometric surfaces, Ag 10 is oxidized and reduces surface Ce 4+ / Ti 4+ ions, while on the O-defective surfaces, the adhesion of silver is promoted only on CeO 2 but unfavored on TiO 2 . On the other hand, on the silver-free supports, O 2 strongly adsorbs at vacancies and preferentially reduces to peroxide. When no O vacancies are considered on the Ag 10 -decorated supports, the net positive charge on Ag 10 actually prevents the adsorption and reduction of O 2 . Instead, when O vacancies are included, two reaction pathways are observed; oxygen molecules can weakly absorb on the silver cluster as a superoxide moiety or strongly adsorb at the vacancy as peroxide. The dissociation of the O−O bond of the peroxide is favored both from the thermodynamic and kinetic points of view in silver-decorated surfaces, in contrast with the silver-free cases. In addition, Ag 10 /CeO 2 shows higher activity toward the O 2 adsorption and dissociation than Ag 10 /TiO 2 , which can be related both to the higher ionicity and superior electron storage/release ability of ceria with respect to titania, thus leading to the weakening of the O−O bond and providing lower activation barriers for oxygen reduction. These results deepen the current understanding of the reactivity of metal/metal oxide composites toward O 2 , especially elucidating how the surface stoichiometry affects the charge state of the metal clusters, and hence the reactivity of these interfaces toward O 2 , with potential important consequences when such composites are considered for catalytic applications.

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CeO2 promoted Ag/TiO2 catalyst for soot oxidation with improved active oxygen generation and delivery abilities

Cited by 36 publications

References 45 publications

Catalytic Materials for Gasoline Particulate Filters Soot Oxidation

Catalytic Materials for Gasoline Particulate Filters Soot Oxidation

Soot Oxidation in Diesel Exhaust on Silver Catalyst Supported by Alumina, Titanium and Zirconium

O₂ Activation over Ag-Decorated CeO₂(111) and TiO₂(110) Surfaces: A Theoretical Comparative Investigation

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CeO2 promoted Ag/TiO2 catalyst for soot oxidation with improved active oxygen generation and delivery abilities

Cited by 36 publications

References 45 publications

Catalytic Materials for Gasoline Particulate Filters Soot Oxidation

Catalytic Materials for Gasoline Particulate Filters Soot Oxidation

Soot Oxidation in Diesel Exhaust on Silver Catalyst Supported by Alumina, Titanium and Zirconium

O2 Activation over Ag-Decorated CeO2(111) and TiO2(110) Surfaces: A Theoretical Comparative Investigation

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O₂ Activation over Ag-Decorated CeO₂(111) and TiO₂(110) Surfaces: A Theoretical Comparative Investigation