Any solid oxide-originated catalyst is extremely heterogeneous due to several factors. First, it may consist of various phases, each exposing different surfaces characterized by different electronic, and thus catalytic, properties. However, even a particular surface of a chosen phase is heterogeneous as it consists of different chemical elements connected in polyhedra bonded with each other via corners and/or edges and/or walls. In addition, dopants and supports change properties of the surface by enriching its heterogeneity. In the following, the role of dopants as potential sources of surface heterogeneity is discussed, using vanadia as an example.