Catalyst intended for cleaning of combustion gases

Method for producing selective catalysts, especially for exhaust-gas cleaning, in which the selectivity can be chosen as a result of an active base catalyst being doped to the desired specific selectivity. The chemical composition of the catalyst is constituted by a doped host metallic oxide, which emits exo-electrons at the pressure and temperatures prevailing (for example, in a combustion engine), whereby electron vacancies brought about by this electron emission arise in the crystal lattice of the doped host metallic oxide and the energy levels of which are clearly determined by the previous binding energies of the emitted electrons in the crystal lattice of the host metallic oxide, whereby the selectivity is obtained by virtue of the fact that only those molecules or parts of molecules whose intermolecular repulsion energy is consistent with the energy levels of the electron vacancies formed in the surface layer of the catalyst particle bind to these vacancies and are hence able to form part of the common electron structure between reactant and reagent which is the precondition for a reaction to the pure, doped and selective catalyst particles being able to take place.