Development and Characterization of Electro- and Photo-Electrochemical Systems for High-Added-Value Products

Abstract

The main challenge in the development of electrochemical and photoelectrochemical systems is the kinetics of the anodic oxygen evolution half-reaction (OER), which is intrinsically slow. For this reason, in this thesis all efforts have been devoted to elaborate strategies that allow a better exploitation of the oxidative process in (photo)-electrochemical cells. Among these strategies, on the one hand, porous electrodes based on pencil graphite rods and doped with NiFe have provided a large surface area and have been used for the electrochemical oxidation of water to oxygen. On the other hand, new oxidation systems have been employed, such as the photoelectrochemical oxidation of primary alcohols, which have allowed the selective synthesis of organic chemical products with high added value. Finally, a set of characterization techniques including structural and morphological techniques, as well as analytical and electrochemical methods, have allowed us to differentiate and understand the processes that take place in the (photo)-electrochemical cells studied. Among the different techniques used, impedance spectroscopy has proved to be fundamental for the determination of surface states related to these processes.