Understanding the mechanism of photo catalytic reactions is a key to systematically improve their efficiency and therewith enhance substantially the impact of green chemistry. Photo catalytic reactions are determined by the electronic level alignment between a catalyst and the reactant. This energy level alignment depends strongly on the local morphology of the catalyst and the absorption site of the reactant but is only poorly understood due to the difficulty to study photo catalytic reactions at the molecular length scale – the critical length scale for photo-catalytic processes.This project focuses on understanding the local electronic structure of catalyst and adsorbed reactant spectroscopically with molecular scale resolution and compare it to the local photo catalytic reactivity using state of the art Near Field Optical Microscopy and Ultra High Vacuum and Low Temperature Scanning Tunneling Microscopy. Semiconducting iron oxide nano wires will be studied as catalyst since this system is specifically promising for photo catalysis in combination with molybdenum hexa carbonyl as reactant model system. This challenging work will be realized by leveraging the unique expertise in surface catalytic reactions and nano scale electronic structure characterization at the Lawrence Berkeley National Laboratory and the Max Planck Institute for Nanoscale Science in Stuttgart respectively.The fast paste, inspiring and highly interdisciplinary environment at both institutions together with their career development programs for PostDoctoral fellows, and the challenging aspect of combining the expertise from varies fields to succeed with the proposed project will inevitably allow the applicant to develop as an independent and emerging researcher in the field of photo catalysis, creating the base for a highly successful scientific career.