Structured automotive catalysts which comprise a plurality of different catalytically active coatings arranged above one another on a support body and whose coatings contain transition metals and porous support materials are well known. Structured automotive catalysts of this type which do not belong to the group of three-way catalysts, in particular, frequently display large selectivity losses after thermal aging processes which can be attributed to the thermally induced migration of transition metal atoms from one layer into the neighboring coating. The introduction of a diffusion barrier which slows or prevents the thermally induced migration of transition metal atoms from one catalytically active layer into the other increases the thermal aging stability of such catalysts significantly.