The Solar Thermal Redoxchemical Production of Hydrogen Using Cerium Oxide 3D-Printed Receiver Modules 

Lithoz/AT has delivered an industry-leading CeraFab System S65 to the WZR ceramic solutions GmbH/DE. The printer will support its DLR (German Aerospace Centre)-partnered project, working on generating green hydrogen via a solar-thermochemical process. As a “receiver module”, the CeO2 assembly is heated up to 1400–1500 °C. The ideal shape lattice design (to be defined between WZR and DLR) will ensure that heat pene­trates as deeply as possible into the complex part’s structure, making the process as efficient as possible. Within that desired temperature window, cerium oxide releases a fraction of oxygen to the atmosphere. The resulting sesquioxide is still ­stable in its original phase (meaning no phase change affecting the macro-structure) but it has a higher redox chemical energy level which can now be exploited. Therefore, the activated cerium sesquioxide receiver module is moved down inside the tower power plant and cooled down. Once it reaches a certain temperature, water vapour is introduced. In contact with the hot surface, the vapour splits into hydrogen (H2) and oxygen (O2), thermodynamically driven by the diffusion of oxygen into the material bulk to refill the “empty oxygen sites”. H2 remains and enriches the sweeps flux. After this relax­ation, the receiver component can re-enter the reduction process by heating it up again – the cycle restarts from the beginning. The aim is to achieve a specimen stability of several thousand redox cycles. The resulting “green” hydrogen has therefore been exclusively generated by a redoxchemical process only made possible by solar energy and a 3D-printed ceramic key component.


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