Surface differences of oxide nanocrystals determined by geometry and exogenously coordinated water molecules. Issue 37 (14th September 2022) - Chen, Junchao
Abstract : Both atomic geometry and the influence of surroundings ( e.g., exogenously coordinated water) are key issues for determining the chemical environment of oxide surfaces, whereas the latter is usually ignored and should be considered in future studies. Abstract : Determining the different surfaces of oxide nanocrystals is key in developing structure–property relations. In many cases, only surface geometry is considered while ignoring the influence of surroundings, such as ubiquitous water on the surface. Here we apply 17 O solid-state NMR spectroscopy to explore the facet differences of morphology-controlled ceria nanocrystals considering both geometry and water adsorption. Tri-coordinated oxygen ions at the 1 st layer of ceria (111), (110), and (100) facets exhibit distinct 17 O NMR shifts at dry surfaces while these 17 O NMR parameters vary in the presence of water, indicating its non-negligible effects on the oxide surface. Thus, the interaction between water and oxide surfaces and its impact on the chemical environment should be considered in future studies, and solid-state NMR spectroscopy is a sensitive approach for obtaining such information. The work provides new insights into elucidating the surface chemistry of oxide nanomaterials.