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Excellent Catalytic Activity of a Pd‐Promoted MnO x Catalyst for Purifying Automotive Exhaust Gases
Author(s) -
Hosokawa Saburo,
Shibano Takuya,
Koga Hiroaki,
Matsui Masafuyu,
Asakura Hiroyuki,
Teramura Kentaro,
Okumura Mitsutaka,
Tanaka Tsunehiro
Publication year - 2020
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201902385
Subject(s) - catalysis , chemistry , oxygen , dissociation (chemistry) , metal , palladium , adsorption , hydrocarbon , inorganic chemistry , redox , carbon monoxide , organic chemistry
Currently, there is a strong demand for new automotive catalysts with improved low‐temperature activity and reduced precious metal use. Such catalysts must undergo simultaneous CO/hydrocarbon oxidations and NO reduction. A Pd catalyst supported on Mn‐modified hexagonal YbFeO 3 (Pd/Mn‐YFO) exhibited extremely high activity at low temperature via a Mars‐van Krevelen (MvK) mechanism involving lattice oxygen and oxygen vacancy site in the catalyst support. NO reduction proceeded by high CO and C 3 H 6 oxidation activity of Pd/Mn‐YFO, and the catalytic activity of 1.0 wt% Pd/Mn‐YFO was higher than that of 5.0 wt% Pd/Al 2 O 3 , despite the lower Pd loading. We clarified that the lattice oxygen in MnO x , which existed on the surface of YFO, consumed by CO and C 3 H 6 oxidation was recovered by NO to form N 2 via MvK‐type NO reduction, while the Pd species promoted NO adsorption and dissociation on MnO‐like species.