The main goal of this project is to develop strategies to assemble metal oxide semiconductor-based thin films modified by metallic nanoparticles, coordination compounds or other metal oxides to efficiently promote solar-to-chemical energy conversion, particularly through water oxidation and CO2 reduction. The main idea is to establish clear relationships between composition, structure, morphology and photocatalytic efficiency, in such a way that a detailed understanding on the mechanistic aspects of the process could be reached. Hopefully, the proposed fundamental studies will contribute to the development of up-scalable high efficient devices for solar fuel production.