Surface engineering and immobilization of MgO nanocubes

Fundamental insights into chemical and physical processes which occur on oxide surfaces are vital for their use in a variety of present-day and future industrial applications. These cover the spectrum from fuel cells, sensors, electronic and optoelectronic devices to catalysts and catalyst supports. Polycrystalline materials are generally used in technology. Consequently, the materials` activity is often determined by the combination of different surface planes with different defect densities. Such synergistic effects are not accessible by single crystal surface science studies. In order to elucidate the structure-reactivity relationship on unsupported oxide particles, MgO nanocubes which have a well-defined particle morphology will be used as a model system for surface chemistry studies. The attained nanocrystals` size and shape determines the relative abundance of specific surface elements such as corners and edges. Their characterization and the opportunity to identify their impact on the spectroscopic and chemical properties of the integral particle ensemble will expand our knowledge about the role of surface defects on unsupported oxide nanostructures. Moreover, the chemical surface manipulation of MgO nanocubes will provide efficient means for altering the energy range of light absorption and emission in a controlled way. In order to advance the functionality of MgO nanocubes as thermally stable and morphologically well-defined templates, site-specific surface decoration with selected molecules will be carried out. Coating of MgO nanocubes with metal oxide films will lead to novel heterostructures to be characterized with transmission electron microscopy and molecular spectroscopy. The third objective of the present project is to immobilize alkaline earth oxide nanocrystals in mesoporous host matrices. Infiltration of SiOx-based monoliths with oxide nanocrystals not only offers a way to prevent them from coarsening and agglomeration, it also provides a basis to connect oxide nanoparticles to our macroscopic world. The research project represents an unprecedented step towards surface science on oxide single crystal surfaces, where atomic level understanding already exists for certain surface reactions. As local surface structures on oxide nanoparticles become identified as active sites for the process of interest, surface engineering will represent an entirely new opportunity region for tuning the materials properties.

Fundamental insights into chemical and physical processes which occur on oxide surfaces are vital for their use in a variety of present-day and future industrial applications. These cover the spectrum from fuel cells, sensors, electronic and optoelectronic devices to catalysts and catalyst supports. Polycrystalline materials are generally used in technology. Consequently, the materials` activity is often determined by the combination of different surface planes with different defect densities. Such synergistic effects are not accessible by single crystal surface science studies. In order to elucidate the structure-reactivity relationship on unsupported oxide particles, MgO nanocubes which have a well-defined particle morphology will be used as a model system for surface chemistry studies. The attained nanocrystals` size and shape determines the relative abundance of specific surface elements such as corners and edges. Their characterization and the opportunity to identify their impact on the spectroscopic and chemical properties of the integral particle ensemble will expand our knowledge about the role of surface defects on unsupported oxide nanostructures. Moreover, the chemical surface manipulation of MgO nanocubes will provide efficient means for altering the energy range of light absorption and emission in a controlled way. In order to advance the functionality of MgO nanocubes as thermally stable and morphologically well-defined templates, site-specific surface decoration with selected molecules will be carried out. Coating of MgO nanocubes with metal oxide films will lead to novel heterostructures to be characterized with transmission electron microscopy and molecular spectroscopy. The third objective of the present project is to immobilize alkaline earth oxide nanocrystals in mesoporous host matrices. Infiltration of SiOx-based monoliths with oxide nanocrystals not only offers a way to prevent them from coarsening and agglomeration, it also provides a basis to connect oxide nanoparticles to our macroscopic world. The research project represents an unprecedented step towards surface science on oxide single crystal surfaces, where atomic level understanding already exists for certain surface reactions. As local surface structures on oxide nanoparticles become identified as active sites for the process of interest, surface engineering will represent an entirely new opportunity region for tuning the materials properties.