| Titre : | Structure of Cs0.5[Nb2.5W2.5O14] analysed by focal-series reconstruction and crystallographic image processing (2011) |
| Auteurs : | Juri Barthel, Auteur ; Thomas E. Weirich, Auteur ; Gerhard Cox, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Acta materialia (Vol. 58 N° 10, Juin 2010) |
| Article en page(s) : | pp. 3764–3772 |
| Note générale : | Métallurgie |
| Langues : | Anglais |
| Tags : | High-resolution transmission electron microscopy (HRTEM) Focal-series reconstruction Crystallographic image processing (CIP) Density functional theory (DFT) |
| Résumé : | The structure of the oxygen sub-lattice in Cs0.5[Nb2.5W2.5O14] is investigated for the first time by advanced electron-optical methods. Since Cs0.5[Nb2.5W2.5O14] resembles the crystal structure of the so-called M1 phase of Mo–V–Nb–Te–O, which is the best catalyst for the selective oxidation of propane to acrylic acid, the structure analysis of the oxygen sub-lattice can contribute substantially to a better understanding of this catalytic process. The so far only partially known structure of the complex metal oxide Cs0.5[Nb2.5W2.5O14] is investigated by combining modern methods of high-resolution transmission electron microscopy with crystallographic image processing techniques. Average atom positions in the a–b plane are determined from the phase of the exit-plane wave function, which was numerically reconstructed from a focal series of spherical-aberration-corrected electron micrographs. The experimentally determined atom positions agree well with a structure model obtained by first-principles calculations for the underlying M5O14 (M = Nb, W) framework. Moreover, several deviations from the periodic structure, which may influence the catalytic properties of the structurally similar M1 phase, are observed. The obtained results demonstrate that aberration-corrected high-resolution transmission electron microscopy is a reliable alternative for the analysis of periodic structures, in particular when traditional methods for crystallographic structure determination like XRD or neutron diffraction cannot be applied. |
| DEWEY : | 669 |
| ISSN : | 1359-6454 |
| En ligne : | http://www.sciencedirect.com/science/article/pii/S1359645410001618 |
