Patent ID: 8383544

Claim:
A process for reactivating a thermally aged nitrogen oxide storage catalyst which comprises, in addition to platinum as a catalytically active component, basic strontium or barium compounds or strontium and barium compounds on a support material comprising cerium oxide, and additionally comprises ternary mixed oxides formed from strontium and/or barium compounds, cerium oxide, and platinum, and which is used for emission control in a motor vehicle with a lean-burn engine, which comprises a first process step of releasing catalytically active platinum from the ternary mixed oxides by heating the catalyst in a reducing agent-containing gas mixture to a temperature between 100° C and 500° C, and then a second process step, which is offset in time with the first process step, of converting the strontium and/or barium cerates resulting from the first process step into strontium oxide and/or barium oxide by treating the catalyst with a nitrogen dioxide- and water vapor-containing gas mixture at temperatures between 300° C and 500° C.