Spatial Distribution of the Vanadium Atomic Species in MoVTeO and MoVTeNbO Oxide Catalysts as Revealed by High‐Angle Annular Dark‐Field Scanning Transmission Electron Microscopy

High‐angle annular dark‐field scanning transmission electron microscopy (STEM–HAADF) was used to characterize a light‐alkane mild‐oxidation catalyst corresponding to two different MoVTe(Nb)O M1 phases. For that purpose a semiautomatic integration routine was developed, which allows the analysis of several hundred atomic columns with a normalization procedure to quantitatively determine the vanadium content of mixed (V, Mo) crystallographic sites with a low statistical variability. The obtained results were compared with data previously obtained on other M1 phases with different compositions. The comparison showed that the V distribution over the sites was not strongly influenced by the presence or absence of niobium, the method of synthesis used, and the nature of the Te or Sb cations in the hexagonal channels, but depended mainly on the total V content of the phases. Extrapolation to low V content enabled a discussion on the possible location of the vanadium active sites. Probing the vanadium content: A light‐alkane mild‐oxidation catalyst corresponding to two different MoVTe(Nb)O M1 phases was characterized by high‐angle annular dark‐field scanning transmission electron microscopy (STEM–HAADF). Comparison with previous data reveals that the vanadium distribution depends mainly on the total V content of the phases.