"Low-temperapture polymer electrolyte membran fuel cells (LT-PEMFC) have been attracting great attention as a promising clean power generator. The primary reaction taking place at the cathode is the oxygen reduction reaction (ORR), which is traditionally catalysed by platinum. Commercialisation of the technology requires lower price, lower overpotential and higher stability of the electro-catalyst.The present proposal aims at exploring structure-reactivity correlations of four types of Pd-based model catalyst as base platforms for a rational ORR electro-catalyst design: (1) high and low index Pt(hkl) and Pd(hkl) single crystals; (2) Pt and mixed Pt-M (M= Fe, Co, Ni) films on Pd(hkl); (3) tailored Pt and Au nanoparticles on Pd(hkl); and (4) palladium-platinum alloy electrodes PdxPty of various composition and crystal orientation. Electrochemical reactivity studies will be combined with novel state-of-the-art in-situ imaging and spectroscopic techniques for monitoring local structure and reactivity. In particular, the applicant will employ in-situ Conductive-Probe Atomic Force Microscopy (CP-AFM) and the novel Raman spectroscopic technique SHINERS, capable for probing processes on well-definded single crystal surfaces under electrochemical operating conditions. This approach allows to explore in-situ the role of adsorbed intermediates as wll as spectators, such as OHads, anions, formation of surface oxides, and will provide unprecedented fundamantal knowledge on basic reaction mechanisms at nanoscale. The experimental work at Bern University will benefit from complementary DFT-type model calculations (collaboration with T. Jacob), and joined application studies with the technology-driven Electrochemistry Laboratory at PSI.The project also aims to build a strong connection of people, knowledge and skills between Europe and Japan for future collaboration."