Redox Materials in Hydrogen Production : Investigation of state-of-the-art redox materials in thermochemical cycles for hydrogen production via solar energy

Sammanfattning: This bachelor thesis work has investigated different redox materials in 2-step thermochemical water splitting processes for solar-driven hydrogen production. Materials have been mapped out by their results from experimental activity and by the conditions the tests were conducted in. Key materials, which seem to be the most promising for future real-life applications, have been noticed from that information. The investigated material groups are Ceria and some materials included in the group of Perovskites structure. The former is a metal oxide that is the most well-established redox material for this application and the latter is a rather new and uncharted alternative material family. Among the materials studied, LaFe0.9Ni0.1O3 exhibit the highest yield of hydrogen, reaching 6390 μmol/gmaterial. Additionally, LaCo0.6Fe0.4O3 demonstrated notable performance, producing 2200 μmol/gmaterial at a relatively low temperature of 700ºC. In addition to these findings, an experimental activity involving a Perovskite with the composition of Sr2FeMo0.6Ni0.4O6 was conducted. However, due to issues with the test setup and residual water affecting the process, the activities were severely delayed and exceeded the time schedule of this work. Nevertheless, the preliminary results are presented, indicating its viability as an oxygen carrier in the process. Finally, this study summarizes the research on these oxygen-carrying materials and identifies state-of-art options. The quantified results demonstrate that Ceria’s hydrogen-producing capacity is limited by the Tred in a way that it necessarily isn’t for Perovskites. Small differences in the A- and B-sites of the Perovskite composition can result in vastly different thermodynamic and kinetic properties. In all, manipulating Perovskites molecular compositions seem effective and the chances of finding an optimal redox material for this application, amongst this material family, can be considered high.