Crystallographic shear defect in molybdenum oxides: Structure and TEM of molybdenum sub-oxides Mo18O52 and Mo8O23

Molybdenum trioxide and molybdenum sub-oxides are of great interests in catalysis due to their utilities as model system to elucidate the correlations between the structure and the catalytic performance. The suboxides are usually an intermediate phase during catalytic reaction in which the lattice oxygen is involved. We show the identification of the two common molybdenum sub-oxides Mo18O52 and Mo8O23, derived from MoO3 by crystallographic shearing (CS), by means of electron diffraction and High-Resolution Transmission Electron Microscopy (HRTEM) in combination with image simulation. The coincidence of simulated electron diffraction patterns and high-resolution images with the experimental ones indicates the feasibility of CS structure determination by these techniques.