Chemical looping hydrogen production (CLHP) using iron-based oxygen carriers is a promising route for sustainable hydrogen generation with inherent CO2 separation. The aim of this project to develop a computational understanding of the redox behaviour of iron oxides in a three-reactor chemical looping process consisting of an air reactor, fuel reactor, and steam reactor. The study will focus on the key iron oxide phases involved during redox cycling, namely hematite, magnetite, and wüstite, which control oxygen release, oxygen transport, and hydrogen production. The project will combine machine-learning-assisted structure screening with density functional theory calculations. Machine-learning interatomic potentials will first be used to rapidly evaluate a large number of bulk, defective, and surface structures. This will allow efficient pre-screening of oxygen vacancy sites, migration pathways, and surface configurations, so that low-priority structures can be discarded at an early stage. The most relevant structures and reaction pathways will then be investigated in detail using DFT calculations with VASP. Spin polarization and Hubbard U corrections will be included to properly describe the localized Fe 3d electrons and changes in Fe oxidation states during reduction and oxidation. The main computational tasks will include structural relaxation of Fe2O3, Fe3O4, and FeO phases, calculation of oxygen vacancy formation energies, and evaluation of oxygen migration barriers using the climbing-image nudged elastic band method. These calculations will clarify oxygen transport from the bulk to the surface, which is a key factor governing the redox performance of iron-based oxygen carriers. In addition, surface reaction mechanisms relevant to the fuel and steam reactors will be studied. Reactions involving CO, H2, CH4, and H2O will be considered to understand CO2 formation, H2O formation, methane activation, and H2 production during water splitting. A particular focus will be placed on water splitting on magnetite and wüstite surfaces, where oxygen vacancies are expected to strongly influence H₂ formation. The thermodynamics of re-oxidation in the air reactor will also be evaluated to complete the full chemical looping cycle. Electronic structure analysis, including charge, spin, density of states, and bonding descriptors, will be used to connect Fe–O bonding, oxygen mobility, and reaction barriers. The project will provide atomistic insight into how iron oxide oxygen carriers operate across the fuel, steam, and air reactors. The results will support the design of improved iron-based and multimetallic oxygen carriers with enhanced oxygen transport, redox stability, and hydrogen production performance.