A catalytic NOx reduction system using periodic two steps: An operation in oxidizing conditions and a relatively short operation in reducing conditions

Veikko Komppa, Tadao Nakatsuji (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

21 Citations (Scopus)

Abstract

Catalytic lean NO reduction system in periodic two steps, an operation in oxidizing conditions and a relatively short operation in reducing conditions, has been investigated using Rh-based catalysts that can hardly adsorb any nitrogen dioxide. The investigation was done using a pulse reaction with a pulse-injected reductant, a continuous pulse reaction in the periodic two steps, temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO) and transmission electron microscope (TEM). In the pulse reaction, after hydrogen or CO was pulse-injected for a moment to achieve reducing conditions, the highly dispersed Rh catalyst could catalyze NO reduction at 200–400°C in oxidizing conditions for about 1 min. Furthermore, after the highly dispersed Rh supported on beta-zeolite was exposed to the gas composed of 3% of O2, 40 ppm of SO2 and balance He at 300 and 400°C for 24 h, NO was effectively reduced. The highly dispersed Rh supported on a beta-zeolite was reduced with hydrogen at a much lower temperature range and oxidized with oxygen at a much higher temperature range than Rh based catalysts with Rh particle size of several nm.
Original languageEnglish
Pages (from-to)209-223
Number of pages15
JournalApplied Catalysis B: Environmental
Volume30
Issue number1-2
DOIs
Publication statusPublished - 2001
MoE publication typeA1 Journal article-refereed

Fingerprint

Time varying systems
catalyst
Zeolites
zeolite
hydrogen
Catalysts
Hydrogen
nitrogen dioxide
Nitrogen Dioxide
Temperature
Reducing Agents
Carbon Monoxide
temperature
particle size
oxidation
electron
oxygen
Electron microscopes
Gases
Particle size

Keywords

  • NOx reduction
  • Rhodium
  • Zeolite
  • TPR
  • TPO

Cite this

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title = "A catalytic NOx reduction system using periodic two steps: An operation in oxidizing conditions and a relatively short operation in reducing conditions",
abstract = "Catalytic lean NO reduction system in periodic two steps, an operation in oxidizing conditions and a relatively short operation in reducing conditions, has been investigated using Rh-based catalysts that can hardly adsorb any nitrogen dioxide. The investigation was done using a pulse reaction with a pulse-injected reductant, a continuous pulse reaction in the periodic two steps, temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO) and transmission electron microscope (TEM). In the pulse reaction, after hydrogen or CO was pulse-injected for a moment to achieve reducing conditions, the highly dispersed Rh catalyst could catalyze NO reduction at 200–400°C in oxidizing conditions for about 1 min. Furthermore, after the highly dispersed Rh supported on beta-zeolite was exposed to the gas composed of 3{\%} of O2, 40 ppm of SO2 and balance He at 300 and 400°C for 24 h, NO was effectively reduced. The highly dispersed Rh supported on a beta-zeolite was reduced with hydrogen at a much lower temperature range and oxidized with oxygen at a much higher temperature range than Rh based catalysts with Rh particle size of several nm.",
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A catalytic NOx reduction system using periodic two steps : An operation in oxidizing conditions and a relatively short operation in reducing conditions. / Komppa, Veikko; Nakatsuji, Tadao (Corresponding Author).

In: Applied Catalysis B: Environmental, Vol. 30, No. 1-2, 2001, p. 209-223.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - A catalytic NOx reduction system using periodic two steps

T2 - An operation in oxidizing conditions and a relatively short operation in reducing conditions

AU - Komppa, Veikko

AU - Nakatsuji, Tadao

PY - 2001

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N2 - Catalytic lean NO reduction system in periodic two steps, an operation in oxidizing conditions and a relatively short operation in reducing conditions, has been investigated using Rh-based catalysts that can hardly adsorb any nitrogen dioxide. The investigation was done using a pulse reaction with a pulse-injected reductant, a continuous pulse reaction in the periodic two steps, temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO) and transmission electron microscope (TEM). In the pulse reaction, after hydrogen or CO was pulse-injected for a moment to achieve reducing conditions, the highly dispersed Rh catalyst could catalyze NO reduction at 200–400°C in oxidizing conditions for about 1 min. Furthermore, after the highly dispersed Rh supported on beta-zeolite was exposed to the gas composed of 3% of O2, 40 ppm of SO2 and balance He at 300 and 400°C for 24 h, NO was effectively reduced. The highly dispersed Rh supported on a beta-zeolite was reduced with hydrogen at a much lower temperature range and oxidized with oxygen at a much higher temperature range than Rh based catalysts with Rh particle size of several nm.

AB - Catalytic lean NO reduction system in periodic two steps, an operation in oxidizing conditions and a relatively short operation in reducing conditions, has been investigated using Rh-based catalysts that can hardly adsorb any nitrogen dioxide. The investigation was done using a pulse reaction with a pulse-injected reductant, a continuous pulse reaction in the periodic two steps, temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO) and transmission electron microscope (TEM). In the pulse reaction, after hydrogen or CO was pulse-injected for a moment to achieve reducing conditions, the highly dispersed Rh catalyst could catalyze NO reduction at 200–400°C in oxidizing conditions for about 1 min. Furthermore, after the highly dispersed Rh supported on beta-zeolite was exposed to the gas composed of 3% of O2, 40 ppm of SO2 and balance He at 300 and 400°C for 24 h, NO was effectively reduced. The highly dispersed Rh supported on a beta-zeolite was reduced with hydrogen at a much lower temperature range and oxidized with oxygen at a much higher temperature range than Rh based catalysts with Rh particle size of several nm.

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KW - Rhodium

KW - Zeolite

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KW - TPO

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DO - 10.1016/S0926-3373(00)00235-6

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JO - Applied Catalysis B: Environmental

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SN - 0926-3373

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