| 초록 |
In recent, we are intensively conducting the experimental analyses of electronic structure effect of electrocatalysts on fuel cell performance, especially, oxygen reduction reaction (ORR) for PEMFC cathode and methanol oxidation reaction (MOR) for DMFC anode, based on d-band center model which is an advanced form of Newns-Anderson model. The electronic structure was tuned by two methods: size and shape control. The size of Pt nanoparticles supported on carbon nanotubes was finely controlled with single atom to cluster (SAC) approach. The d-band center position of electrocatalysts was clearly down-shifted with the decrease of particle size by the quantum size effect, so that the enhanced electrocatalytic activity was obtained for smaller particles in ORR and MOR. In terms of shape change, since the proportion of surface atom can be varied with the shape, the changed surface tension gave rise to the variation of electronic structure and electrocatalytic activity. Such results were mainly obtaiend with EXAFS, HR-PES studies in the large synchrotron facilities, such as Spring-8 (Japan), APS (USA) and PLS (Korea) in combination with the first principle calculation. |
