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Inhibition of Ammonia Poisoning by Addition of Platinum to Ru/α‐Al 2 O 3 for Preferential CO Oxidation in Fuel Cells
Author(s) -
Sato Katsutoshi,
Yagi Sho,
Zaitsu Shuhei,
Kitayama Godai,
Kayada Yuto,
Teramura Kentaro,
Takita Yusaku,
Nagaoka Katsutoshi
Publication year - 2014
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201402583
Subject(s) - ruthenium , catalysis , platinum , prox , chemistry , carbon monoxide , inorganic chemistry , xanes , catalytic reforming , spectroscopy , organic chemistry , physics , quantum mechanics
In polymer electrolyte fuel cell (PEFC) systems, small amounts of ammonia (NH 3 ) present in the reformate gas deactivate the supported ruthenium catalysts used for preferential oxidation (PROX) of carbon monoxide (CO). In this study, we investigated how the addition of a small amount of platinum to a Ru/α‐Al 2 O 3 catalyst (Pt/Ru=1:9 w / w ) affected the catalyst’s PROX activity in both the absence and the presence of NH 3 (130 ppm) under conditions mimicking the reformate conditions during steam reforming of natural gas. The activity of undoped Ru/α‐Al 2 O 3 decreased sharply upon addition of NH 3 , whereas Pt/Ru/α‐Al 2 O 3 exhibited excellent PROX activity even in the presence of NH 3 . Ruthenium K‐edge X‐ray absorption near‐edge structure (XANES) spectra indicated that in the presence of NH 3 , some of the ruthenium in the undoped catalyst was oxidized in the presence of NH 3 , whereas ruthenium oxidation was not observed with Pt/Ru/α‐Al 2 O 3 . These results suggest that ruthenium oxidation is retarded by the platinum, so that the catalyst shows high activity even in the presence of NH 3 .