The reduction of NO with H-2 and the oxidation of CO with O-2 were investig
ated over silica- and alumina supported gold/metal oxide catalysts (M: Co,
La, Ce). In general, the silica supported samples were less active than the
alumina supported ones, probably due to the presence of large gold particl
es. The presence of metal oxide was beneficial to the activity in the NO/H-
2 reaction and the CO/O-2 reaction over Au/SiO2. Opposite behavior was obse
rved with the NO reduction over Au/Al2O3 where the metal oxide might cover
active species. Addition of cobalt oxide and lanthana improves the selectiv
ity towards N-2. (C) 1999 Elsevier Science B.V. All rights reserved.