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Operando UV/Vis Analysis of the Synergy Effect between Copper and Gold in Nitric Oxide Reduction over Gold and Copper on Alumina Catalysts
Author(s) -
Kondratenko Evgenii V.,
Takahashi Naoki,
Nagata Naoto,
Ibe Masaya,
Hirata Hirohito,
Takahashi Hiroaki
Publication year - 2015
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.201500626
Subject(s) - copper , catalysis , calcination , metal , chemistry , polyol , inorganic chemistry , reducing agent , inert gas , inert , materials science , organic chemistry , polyurethane
Mono‐ (Cu or Au) and bi‐metallic AuCu nanoparticles were prepared by a modified polyol reduction method and deposited onto Al 2 O 3 followed by calcination at 500 °C in air. The synthesised catalysts were tested for their activity for NO reduction with CO in excess H 2 O between 50 and 500 °C at a contact time relevant for automotive convertors. The bi‐metallic catalysts showed a significantly higher activity than Cu/Al 2 O 3 and Au/Al 2 O 3 , and the latter was inert for the target reaction. In addition, the activity depended greatly on the Au/Cu ratio, which thus demonstrates a synergy effect between these two metals. Operando UV/Vis spectroscopy provided direct evidence for the transformation of initially oxidised CuO x species into metallic Cu 0 , which is the only active species for NO reduction. Promotion with Au was found to accelerate the reduction of Cu 2+ /Cu + to Cu 0 .