NOx storage and reduction over copper-based catalysts. Part 2: Ce0.8M0.2Oδ supports (M = Zr, La, Ce, Pr or Nd)

Agustín Bueno-López*, Dolores Lozano-Castelló, James A. Anderson

*Corresponding author for this work

Research output: Contribution to journalArticle

9 Citations (Scopus)
5 Downloads (Pure)

Abstract

5% copper catalysts with Ce0.8M0.2Oδ supports (M = Zr, La, Ce, Pr or Nd) have been studied by rapid-scan operando DRIFTS for NOx Storage and Reduction (NSR) with high frequency (30 s) CO, H2 and 50%CO + 50%H2 micropulses. In the absence of reductant pulses, below 200-250 °C NOx was stored on the catalysts as nitrite and nitro groups, and above this temperature nitrates were the main species identified. The thermal stability of the NOx species stored on the catalysts depended on the acid/basic character of the dopant (M more acidic = NOx stored less stable ⇒ Zr4+ <none <Nd3+ <Pr3+ <La3+ ⇐ M more basic = NOx stored more stable). Catalysts regeneration was more efficient with H2 than with CO, and the CO + H2 mixture presented an intermediate behavior, but with smaller differences among the series of catalyst than observed using CO alone. N2 is the main NOx reduction product upon H2 regeneration. The highest NOx removal in NSR experiments performed at 400 °C with CO + H2 pulses was achieved with the catalyst with the most basic dopant (CuO/Ce0.8La0.2Oδ) while the poorest performing catalyst was that with the most acidic dopant (CuO/Ce0.8Zr0.2Oδ). The poor performance of CuO/Ce0.8Zr0.2Oδ in NSR experiments with CO pulses was attributed to its lower oxidation capacity compared to the other catalysts.

Original languageEnglish
Pages (from-to)234-242
Number of pages9
JournalApplied Catalysis B: Environmental
Volume198
Early online date28 May 2016
DOIs
Publication statusPublished - 5 Dec 2016

Fingerprint

Carbon Monoxide
Catalyst supports
Copper
catalyst
copper
Catalysts
Doping (additives)
Catalyst regeneration
regeneration
Reducing Agents
Nitrites
Nitrates
Thermodynamic stability
nitrite
Experiments
experiment
Oxidation
Acids
nitrate
oxidation

Keywords

  • Ceria
  • Copper catalyst
  • deNOx
  • Diesel aftertreatment
  • DRIFTS
  • NSR
  • Operando

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology
  • Environmental Science(all)

Cite this

NOx storage and reduction over copper-based catalysts. Part 2 : Ce0.8M0.2Oδ supports (M = Zr, La, Ce, Pr or Nd). / Bueno-López, Agustín; Lozano-Castelló, Dolores; Anderson, James A.

In: Applied Catalysis B: Environmental, Vol. 198, 05.12.2016, p. 234-242.

Research output: Contribution to journalArticle

Bueno-López, Agustín ; Lozano-Castelló, Dolores ; Anderson, James A. / NOx storage and reduction over copper-based catalysts. Part 2 : Ce0.8M0.2Oδ supports (M = Zr, La, Ce, Pr or Nd). In: Applied Catalysis B: Environmental. 2016 ; Vol. 198. pp. 234-242.
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abstract = "5{\%} copper catalysts with Ce0.8M0.2Oδ supports (M = Zr, La, Ce, Pr or Nd) have been studied by rapid-scan operando DRIFTS for NOx Storage and Reduction (NSR) with high frequency (30 s) CO, H2 and 50{\%}CO + 50{\%}H2 micropulses. In the absence of reductant pulses, below 200-250 °C NOx was stored on the catalysts as nitrite and nitro groups, and above this temperature nitrates were the main species identified. The thermal stability of the NOx species stored on the catalysts depended on the acid/basic character of the dopant (M more acidic = NOx stored less stable ⇒ Zr4+ 3+ <Pr3+ <La3+ ⇐ M more basic = NOx stored more stable). Catalysts regeneration was more efficient with H2 than with CO, and the CO + H2 mixture presented an intermediate behavior, but with smaller differences among the series of catalyst than observed using CO alone. N2 is the main NOx reduction product upon H2 regeneration. The highest NOx removal in NSR experiments performed at 400 °C with CO + H2 pulses was achieved with the catalyst with the most basic dopant (CuO/Ce0.8La0.2Oδ) while the poorest performing catalyst was that with the most acidic dopant (CuO/Ce0.8Zr0.2Oδ). The poor performance of CuO/Ce0.8Zr0.2Oδ in NSR experiments with CO pulses was attributed to its lower oxidation capacity compared to the other catalysts.",
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AU - Bueno-López, Agustín

AU - Lozano-Castelló, Dolores

AU - Anderson, James A.

N1 - Acknowledgements The authors thank the financial support of Generalitat Valenciana (Project PROMETEOII/2014/010 and grant BEST/2014/250), the Spanish Ministry of Economy and Competitiveness (Projects CTQ2015-67597-C2-2-R, MAT2014-61992-EXP, and grant PRX14/00249), and the UE (FEDER funding). We thank Dr. A.J. McCue (University of Aberdeen) for support involving the experimental set-up.

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N2 - 5% copper catalysts with Ce0.8M0.2Oδ supports (M = Zr, La, Ce, Pr or Nd) have been studied by rapid-scan operando DRIFTS for NOx Storage and Reduction (NSR) with high frequency (30 s) CO, H2 and 50%CO + 50%H2 micropulses. In the absence of reductant pulses, below 200-250 °C NOx was stored on the catalysts as nitrite and nitro groups, and above this temperature nitrates were the main species identified. The thermal stability of the NOx species stored on the catalysts depended on the acid/basic character of the dopant (M more acidic = NOx stored less stable ⇒ Zr4+ 3+ <Pr3+ <La3+ ⇐ M more basic = NOx stored more stable). Catalysts regeneration was more efficient with H2 than with CO, and the CO + H2 mixture presented an intermediate behavior, but with smaller differences among the series of catalyst than observed using CO alone. N2 is the main NOx reduction product upon H2 regeneration. The highest NOx removal in NSR experiments performed at 400 °C with CO + H2 pulses was achieved with the catalyst with the most basic dopant (CuO/Ce0.8La0.2Oδ) while the poorest performing catalyst was that with the most acidic dopant (CuO/Ce0.8Zr0.2Oδ). The poor performance of CuO/Ce0.8Zr0.2Oδ in NSR experiments with CO pulses was attributed to its lower oxidation capacity compared to the other catalysts.

AB - 5% copper catalysts with Ce0.8M0.2Oδ supports (M = Zr, La, Ce, Pr or Nd) have been studied by rapid-scan operando DRIFTS for NOx Storage and Reduction (NSR) with high frequency (30 s) CO, H2 and 50%CO + 50%H2 micropulses. In the absence of reductant pulses, below 200-250 °C NOx was stored on the catalysts as nitrite and nitro groups, and above this temperature nitrates were the main species identified. The thermal stability of the NOx species stored on the catalysts depended on the acid/basic character of the dopant (M more acidic = NOx stored less stable ⇒ Zr4+ 3+ <Pr3+ <La3+ ⇐ M more basic = NOx stored more stable). Catalysts regeneration was more efficient with H2 than with CO, and the CO + H2 mixture presented an intermediate behavior, but with smaller differences among the series of catalyst than observed using CO alone. N2 is the main NOx reduction product upon H2 regeneration. The highest NOx removal in NSR experiments performed at 400 °C with CO + H2 pulses was achieved with the catalyst with the most basic dopant (CuO/Ce0.8La0.2Oδ) while the poorest performing catalyst was that with the most acidic dopant (CuO/Ce0.8Zr0.2Oδ). The poor performance of CuO/Ce0.8Zr0.2Oδ in NSR experiments with CO pulses was attributed to its lower oxidation capacity compared to the other catalysts.

KW - Ceria

KW - Copper catalyst

KW - deNOx

KW - Diesel aftertreatment

KW - DRIFTS

KW - NSR

KW - Operando

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