Research Fellows Directory
Dr Luming Peng
University of Cambridge
Because of global warming and rapidly diminishing energy and natural resources, there is increasing concern on the sustainable development of the world, which demands more energy efficient industrial processes. In order to achieve this purpose, new catalytic processes should be designed with higher yield and selectivity to the desired products, at a lower temperature. Nanosized catalysts show great potential because of higher surface area, unique surface / electronic structure. Noble metal nanoparticles supported on nanosized oxides, in particular, attracted much research attention, due to much improved catalytic properties. The interactions between the metal nanoparticles and oxide support are important and in many case, have been claimed as the key to the excellent performances. However, the nature of this interaction, as well as the structure details at the interfaces, remain elusive. The challenges in investigating such problems and solving the structure – property relationship are enormous, since conventional methods to look at the structures of solid materials, such as diffraction, fail in these systems.
We proposed to study the interaction between metal and oxide support with 17O nuclear magnetic resonance (NMR) spectroscopy. NMR spectroscopy gives the resonance frequency (or chemical shift) of nuclei in magnetic field, which are specific and related to the local environment of the nuclei. Since oxygen anions have very large ionic radii, they should be actively involved in interacting with the metal nanoparticles and 17O NMR should be a sensitive approach to this problem. In the past year, we studied the surface structure of oxide nanocrystals preferentially exposing specific facets, and found that the 17O chemical shifts are dependent on the nature of the facets. On the basis of these results, this coming year we will look at the metal nanoparticles on nanocrystals, and try to connect the chemical shifts with the detailed interface structure.
Interests and expertise (Subject groups)