Method for removing carbon monoxide and hydrocarbons from the exhaust gas of lean-burn internal combustion engines

A method for removing carbon monoxide and hydrocarbons from the exhaust gas of lean-burn internal combustion engines, wherein the exhaust gas is passed over a catalyst which contains

• (i) platinum supported on one or more refractory supporting materials,
• (ii) pure cerium oxide, and
• (iii) if the ratio of platinum to cerium oxide is ≦0.5 (calculated as Pt in g/cft:cerium oxide in g/l), an additional noble metal selected from the group consisting of platinum, palladium, rhodium and mixtures thereof,
• wherein the pure cerium oxide (ii) being in close contact with platinum (i) and, if included, additional noble metal (iii),
• wherein, after a limit temperature exposure under lean exhaust gas conditions is exceeded, the catalyst is exposed for a short time to rich exhaust gas to regenerate catalytic activity.