An investigation of a new regeneration method of commercial aged three-way catalysts

Birgersson, Henrik; Boutonnet, Magali; Klingstedt, Fredrik; Murzin, Dmitry Yu.; Stefanov, P.; Naydenov, A.

doi:10.1016/j.apcatb.2005.12.013

Cited by 41 publications

(22 citation statements)

References 28 publications

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“…171 Hydrogen chemisorption was used to determine the dispersion of Pd and particle diameter, and it was calculated that the Pd dispersion was increased following the HCl treatment, while the particle size decreased from 7 to 3 nm. SEM studies determined that there was a large quantity of particles of size 50 to 100 nm present in the aged (sintered) catalyst.…”

mentioning

confidence: 99%

Metal Redispersion Strategies for Recycling of Supported Metal Catalysts: A Perspective

Morgan¹,

Goguet²,

Hardacre³

2015

ACS Catal.

177

152

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Catalyst deactivation is ultimately inevitable, and one of the processes known to cause deactivation is sintering of metal particles. Consequently, numerous methods to reverse the sintering process by re-dispersing metal nanoparticles have been developed. These methods are discussed in this perspective, and the reported mechanisms of re-dispersion are summarized. Additionally, the longer term practical use of such treatments, and the benefits this can bring, is briefly disclosed.

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mentioning

confidence: 99%

Metal Redispersion Strategies for Recycling of Supported Metal Catalysts: A Perspective

Morgan¹,

Goguet²,

Hardacre³

2015

ACS Catal.

177

152

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“…However, the type of Zr also influences the dispersion of cobalt crystallites during the catalyst preparation. Interestingly, when the zirconium oxychloride was employed to prepare catalysts, the oxychlorination conditions could be realized during the calcination step and it could enhance the dispersion of cobalt crystallites by the formation of a mobile MOxCly species [23]. Furthermore, the possibility of oxychlorination could be substantiated in the Cl content as shown in Table 2.…”

Section: Physical Properties Of Crzs Catalystsmentioning

confidence: 97%

“…In the presence of chlorine, the formation of mobile intermediate MOxCly occurs by oxychlorination condition and it increase in number of smaller metal crystallites on the surface [23]. Of noble metals, this is well known phenomena in Pt-based catalysts that are used in catalytic reforming of naphtha.…”

Section: Fischer-tropsch Synthesis Activity and Its Relation To Cobalmentioning

confidence: 99%

“…However the added water can increase the mobility of metal oxide resulting in enhancing the bimetallic entity formation and enlarging the crystallite size. Furthermore, the oxychlorination condition during calcination step is mainly responsible for the redispersion of metal components by forming a mobile intermediate such as MOxCly [23]. Although the CO conversion and product distribution on FTS is mainly affected by the cobalt cluster size and reduction degree [24,25], the cluster size above 6-8 nm has trivial effect on enhancing the intrinsic turn-over frequency (TOF) values [26].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Calcination Temperature on the Activity and Cobalt Crystallite Size of Fischer–Tropsch Co–Ru–Zr/SiO2 Catalyst

et al. 2009

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A series of Co-Ru-Zr/SiO 2 catalysts were prepared by the co-impregnation method in order to understand the effects of calcination temperature on their activity and stability. The crystallite size of cobalt obtained from H 2 chemisorption decreased up to a calcination temperature of 300°C and then increased to reach a reasonably constant value. The activity for CO hydrogenation also increased upto this temperature and then decreased to be stabilized finally at a value smaller than the optimum one. The turn-over frequency values are not significantly altered on the catalysts calcined above 220°C. It was observed that in the presence of chlorine released during the decomposition of the zirconium oxychloride precursor, the dispersion of cobalt crystallites was altered due to the different environment of chlorine and water evolved during the reduction step.

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“…The interest in finding suitable in situ regeneration methods of commercial TWCs has recently grown. The use of liquid solvents, such as weak organic acids (e.g., acetic, oxalic and citric acids) for extraction of contaminants has been reported [11,12], as well as the application of various thermo-chemical treatments using O 2 , H 2 and Cl-containing gas mixtures [13,14] or other Cl-containing reagents (e.g., 1,2-dichloropropane) [15] for the redispersion of large noble metal particles.…”

Section: Introductionmentioning

confidence: 99%

Efficient In-Situ Regeneration Method of the Catalytic Activity of Aged TWC

Christou

Efstathiou

2007

Top Catal

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The expansion of durability of deactivated ''three-way'' catalysts (TWCs) used in gasoline-driven cars by applying efficient, economically viable and environmentally friendly methods for the in situ regeneration of their performance to acceptable levels was investigated. New experimental results on the use of a weak oxalic acid washing solution as a means of an efficient regeneration method of a severely aged (83,000 km mileage) commercial TWC are presented. Oxalic acid is shown to be the most efficient extracting agent of phosphorus, a severe poison of TWCs, among acetic acid, citric acid, NTA and EDTA investigated. X-ray diffraction studies provided strong evidence that washing of the aged TWC results in the removal of CePO 4 , AlPO 4 and (Mg,Ca,Zn) 3 (PO 4 ) 2 type phosphates leading to a significant increase of BET area and pore volume, as well as of CO and NO conversions (catalytic activity tests). The latter is strongly related with the increase in the number of active catalytic sites, as illustrated by in situ DRIFTS studies, after opening closed pores and uncovering additional catalyst surface.

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An investigation of a new regeneration method of commercial aged three-way catalysts

Cited by 41 publications

References 28 publications

Metal Redispersion Strategies for Recycling of Supported Metal Catalysts: A Perspective

Metal Redispersion Strategies for Recycling of Supported Metal Catalysts: A Perspective

Effect of Calcination Temperature on the Activity and Cobalt Crystallite Size of Fischer–Tropsch Co–Ru–Zr/SiO2 Catalyst

Efficient In-Situ Regeneration Method of the Catalytic Activity of Aged TWC

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