Deactivation and Regeneration of Spent Three-Way Automotive Exhaust Gas Catalysts (TWC)

Birgersson, Henrik; Boutonnet, Magali; Järås, Sven; Eriksson, Lars

doi:10.1023/b:toca.0000029786.49989.aa

Cited by 22 publications

(12 citation statements)

References 16 publications

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“…122 TEM images of fresh samples, combined with EDX analysis, confirmed that no noble metal particles of size > 3 nm were present on the monolith. In the aged samples, large agglomerates of metal were observed, including some Pt and Pd particles as large as 100 nm.…”

Section: Other Metals and Bimetallic Catalyst Systemsmentioning

confidence: 87%

“…18,79 In combination with the oxidation and reduction cycles (as discussed in previous section), oxychlorination was also investigated for Pd/Rh monolith catalysts. 122 the addition of chlorine to the oxygen feed (0.8 Cl2, 18% O2, balance N2) resulted in a marked improvement in the activity of the aged catalyst, and this has been attributed to an increased rate of dispersion of the metals on the surface. 174 The greater efficiency of the oxychlorination compared with the oxidation treatment is further reinforced by the fact that the oxychlorination was only conducted for 1 h as opposed to 10 h for the chlorine free treatment.…”

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confidence: 99%

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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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Section: Other Metals and Bimetallic Catalyst Systemsmentioning

confidence: 87%

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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“…Para que haja um bom desempenho dos catalisadores automotivos na conversão simultânea de tais poluentes, são necessárias algumas características estruturais (Biggerson et al, 2004).…”

Section: O Objeto Do Estudounclassified

Análise Multicritério De Materiais Para a Síntese De Catalisadores Automotivos

Sant’Anna¹,

Silva²

2011

Engevista

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resumo: Este artigo estuda o emprego da composição probabilística para avaliar o desempenho de catalisadores automotivos com diferentes composições de materiais. Foram comparados catalisadores à base de óxidos mistos de cério e zircônio impregnados ou não com paládio, e aditivados ou não com alumina impregnada com lantânio. Cada catalisador foi analisado quanto à desativação térmica segundo diferentes condições de envelhecimento. A comparação foi baseada em sete critérios, nos quais cada um dos catalisadores recebeu uma pontuação em escala de Likert de cinco níveis. Para cada catalisador foi calculada a probabilidade de ser o preferido segundo cada critério. Os catalisadores foram, a seguir, ordenados segundo probabilidades de preferência conjunta segundo todos os critérios. palavras-chave: Catalisadores. Escala de Likert. Composição probabilística.Abstract: This paper studies the use of probabilistic composition to evaluate the performance of automotive catalysts with different compositions. The catalysts compared were formed of mixed oxides of cerium and zirconium impregnated or not with palladium, and with no additives or alumina impregnated with lanthanum. Each catalyst was examined for the thermal deactivation under different aging conditions. The comparison was based on seven criteria, in which each of the catalysts received a score in a Likert scale of five levels. For each catalyst was calculated the probability of being the most preferred according to each criterion. The catalysts were then ranked according to the joint probabilistic preference according to all the criteria.

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“…The first category of treatments are employed to reverse the effects of thermal sintering on precious metals through formation of halide complexes of the MO x Cl y type (e.g., M: Pt or Pd), which are volatile, leading to redispersion of the active metal surface [3][4][5]. A decrease of the noble metal particle size results in an increase of the number of active metal sites and interfacial contact area with the Ce x Zr 1-x O 2 solid support, which are proven to recover oxygen storage capacity (OSC) and improve the rate of major TWC reactions [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…Expanding the durability of deactivated automobile TWCs by applying efficient as well as environmentally friendly techniques for the regeneration of their catalytic performance has attracted some scientific attention in the past few years, although TWC technology has been emerged in the mid-1970s. Scientific efforts spent so far in terms of regeneration and reutilization of severely aged TWCs might be classified in the following two main categories: (a) methods that apply thermo-chemical treatments using oxygen, hydrogen, and/ or chlorine-containing gas mixtures [3][4][5], or other chlorine-containing reagents [6][7][8], and (b) methods that involve washing of the catalyst by the use of liquid solvents, such as organic acids [9][10][11][12][13][14][15] or other chelating agents [16,17].…”

Section: Introductionmentioning

confidence: 99%

Regeneration of Aged Commercial Three-Way Catalytic Converters

Christou

Gåsste²,

Karlsson³

et al. 2009

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The present work demonstrates for the first time that rejuvenation of the catalytic activity of full-scale aged commercial three-way catalytic (TWC) converters is feasible after treatment with weak oxalic acid solution (0.1 M). Up to 50% reduction in CO, 75% in NO x and 32% in HC emissions was attained under warm engine driving conditions following regeneration of three aged TWC converters with 42,500, 156,000 and 165,000 km mileage. Efforts to expand the durability of aged commercial TWC converters installed in gasoline-driven cars after applying specific treatments with weak oxalic acid-based solutions appear to be a very promising starting point in recovering to a very large degree their performance.

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Deactivation and Regeneration of Spent Three-Way Automotive Exhaust Gas Catalysts (TWC)

Cited by 22 publications

References 16 publications

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

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

Análise Multicritério De Materiais Para a Síntese De Catalisadores Automotivos

Regeneration of Aged Commercial Three-Way Catalytic Converters

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