Hydrogen is considered essential to reach the European Green Deal and Europe´s clean energy transition. Nowadays, most hydrogen is produced by reforming of fossil fuels. Electrochemical water electrolysis using renewable sources as energy input represents a cleaner way than reforming of fuels to create hydrogen. However, water electrolysis will only be feasible if stable, affordable and effective catalysts for oxygen evolution reaction (OER) are discovered. The research objective of this project is to explore the catalytic activity in OER of Earth abundant transition metal oxides to gain fundamental understanding on the nature of the active sites. To this effect, ordered thin films will be grown, aiming to discover the most active formulations and facets of the crystal structure. This project will be performed at the Fritz-Haber-Institut der Max-Planck-Gesellschaft (MPG), in the department of Interface Science lead by Prof. Roldán Cuenya. MPG was ranked as the third top institution according to the Nature Index 2019. I will work with Dr. Kuhlenbeck, an expert in the surface science field. Merging of his experience in growing thin films with the my background in electrochemical processes is key for the success of the project. During the two years of the project, I will be involved in the dissemination of the results to Academia and the general public through participation in conferences, publication of articles and outreach activities. An individual Career Development Plan, outlined and reviewed by Dr. Kuhlenbeck and Prof. Roldán Cuenya, will be used to monitor the research maturity obtained during the project.