A component part has a catalyst surface. This surface has metallic components and components of MnO2 (13) in contact with the former. The metallic components are preferably formed of Ag and/or Ni. These material pairs achieve a great improvement in catalyst action compared to the pure metals. Especially in the case of use of Ni, which is toxicologically safe, these surfaces, for example, may also find use in ambient air purification for reduction of the ozone content. The surface can be applied, for example, by a coating of the component part, in which case the metallic component and the component of MnO2 are applied in two layers.