Promotive effect of H2O on low-temperature NO reduction by CO over Pd/La0.9Ba0.1AlO3-δ

Takuma Higo, Yuki Omori, Ayaka Shigemoto, Kohei Ueno, Shuhei Ogo, Yasushi Sekine

Research output: Contribution to journalArticle

Abstract

For future removal of NOx by catalysts, low-temperature NO reduction is desired. Results confirmed that a drastic improvement of catalytic activity by H2O on NO–CO–O2 reaction over Pd/La0.9Ba0.1AlO3-δ catalyst at the low temperature of 473 K or below. In a humidified condition, NO reaction with CO on Pd/La0.9Ba0.1AlO3-δ proceeded without being affected by competitive adsorption of NO and CO, whereas that on Pd/Al2O3 was inhibited by strong adsorption of CO on a Pd surface. From in-situ DRIFTS measurements, results showed that nitrite species on the support react with CO adsorbed onto Pd at the periphery of Pd particles and that carbonate species accumulated on Pd/La0.9Ba0.1AlO3-δ are removed rapidly in a humidified condition. Although NO reduction proceeds dominantly on the Pd surface in a dry condition, supplied steam promotes desorption of the surface carbonate to advance the reaction of nitrite with CO for de-NOx in a humidified condition. This mechanism occurs specifically on Pd/La0.9Ba0.1AlO3-δ by virtue of the lattice oxygen and oxygen vacancy on La0.9Ba0.1AlO3-δ.

Original languageEnglish
Pages (from-to)192-197
Number of pages6
JournalCatalysis Today
Volume352
DOIs
Publication statusPublished - 2020 Aug 1

Keywords

  • Effect of water
  • Lattice oxygen
  • NO reduction by CO
  • Pd catalyst

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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