| abstract |
The invention provides a catalyst for catalytically reducing nitrogen oxides in diesel engine exhaust gas by use of unburnt carbon contained in the diesel engine exhaust gas as a reducing agent, the catalyst comprising: n (a) alumina, or n (b) alumina supporting an ion and/or an oxide of at least one transition metal selected from the elements of Period 4 of the Periodic Table, or n (c) alumina supporting an aluminate of at least one transition metal selected from the elements of Period 4 of the Periodic Table. |