The invention provides a catalyst for catalytic reduction of nitrogen
oxides contained in exhaust gases wherein fuel is supplied and subjected
to combustion under periodic rich/lean conditions and the resulting
exhaust gases are brought into contact therewith, which catalyst
comprises: (A) a catalyst component A comprising (c) ceria or (d)
praseodymium oxide or (e) an oxide and/or a composite oxide of at least
two elements selected from the group consisting of cerium, zirconium,
praseodymium, neodymium, terbium, samarium, gadolinium and lanthanum; (B)
a catalyst component B comprising (d) a noble metal catalyst component
selected from the group consisting of platinum, rhodium, palladium and
oxides thereof and (e) a carrier; and (C) a catalyst component C
comprising (f) a solid acid, and (g) a solid acid supporting an oxide of
at least one element selected from the group consisting of vanadium,
tungsten, molybdenum, copper, iron, cobalt, nickel and manganese.