Theoretical and experimental insights into applicability of solid-state 93Nb NMR in catalysis

Ab initio DFT calculations of 93Nb NMR parameters using the NMR-CASTEP code were performed for a series of over fifty individual niobates, and a good agreement has been found with experimental NMR parameters. New experimental and calculated 93Nb NMR data were obtained for several compounds, AlNbO4, VNb9O25, K 8Nb6O19 and Cs3NbO8, which are of particular interest for catalysis. Several interesting trends have been identified between 93Nb NMR parameters and the specifics of niobium site environments in niobates. These trends may serve as useful guidelines in interpreting 93Nb NMR spectra of complex niobium oxide systems, including amorphous samples and niobium-based multicomponent heterogeneous catalysts. Potential applications of 93Nb NMR to study solid polyoxoniobates are discussed. \ua9 2013 The Owner Societies.Peer reviewed: YesNRC publication: Ye