Solar Hydrogen (INNER prosjekt 22)

Secure and abundant energy supply is one of the most important challenges for the global society development on our planet. Hydrogen is the preferable base of an environmentally acceptable energy system, which will be able to eventually replace the fossil fuels on a time scale of 20-50 years. This is because of its advantages for use in mobile applications, energy storage and electrical net load balancing. There is a consensus in literature that the most promising method of hydrogen generation using a ren ewable energy source is based on solar photoelectrochemical (PEC) water decomposition and the overall objective of our project is to acquire a better understanding of the mechanisms behind PEC water splitting focusing primarily on the band gap and doping engineering in the multilayered semiconductor electrodes. The properties of photoelectrodes should satisfy several specific requirements in terms of semiconductor, electrochemistry and chemical stability. Our idea is to development monolithic oxide multil ayered (MOM) electrode concept. In the MOM electrode different oxide components provides the necessary functions, like corrosion stability or efficient light absorption, simultaneously minimizing the risk associated with the formation of isolating layers at the interfaces. One approach for MOM electrodes is to combine a chemically stable protecting layer (for example TiO2 based) thin enough to exhibit carrier tunnelling properties with a CdO/ZnO/MgO multilayer light absorbing structure. Our specific obje ctives are (i) to investigate the optimal profiles of Mg, Zn, and Cd through the MOM structure, (ii) to study electronic doping issues in Zn(MgCd)O and (iii) to study the tunnelling properties of the TiO2 combined with the corrosion resistivity. The proje ct is a part of the SolarH2-network established on behalf of the Nordic Energy Research Association (N-INNER).