Recent progress in investigations of surface structure and properties of solid oxide materials with nuclear magnetic resonance spectroscopy

Abstract

Solid oxide materials have widespread applications which are often associated with their surface structure and properties. Solid-state nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful methods that give detailed local structural information of solid materials. Recent developments in dynamic nuclear polarization (DNP) NMR spectroscopy and 17O surface-selective isotopic labeling provide more opportunities in investigations of surface structure and properties of oxide materials. We describe in this review some of the latest progress in this field. DNP NMR can enhance the sensitivity of surface sites on the oxides by one to two order of magnitude, making very low concentrated species on the surface of oxides visible in NMR spectroscopy. On the basis of surface-selective 17O isotopic labeling, 17O NMR spectroscopy is now able to distinguish surface oxygen species on the different facets or different surface layers in oxide nanostructures. The nature of these facets can also be probed with help of 31P NMR spectroscopy along with phosphorous-containing probe molecules.