Tailoring SLAM perovskites for solar thermochemical hydrogen production: Synthesis, stability and characterization

Solar thermochemical hydrogen (STCH) production is a promising pathway for sustainable hydrogen generation through the utilization of concentrated solar energy. In this study, Sr 0 . 6 La 0 . 4 Mn 0 . 6 Al 0 . 4 O 3-δ (SLAM) perovskite was synthesized, characterized and evaluated as a stable, low-cost, and earth-abundant redox material for STCH applications. Two synthesis routes of the solid-state reaction and the modified Pechini methods were employed to investigate the influence of processing parameters such as precursor type, calcination temperature, and reaction time on phase formation, microstructural evolution and redox performance of the synthesized materials. Structural and morphological analyses were conducted using XRD, BET, FESEM, UV-Vis, PL, FTIR, Raman, and XPS techniques. Redox activity was evaluated through temperature-programmed reduction and oxidation cycling, focusing on oxygen release (δ) and recovery (β). The results confirmed the successful formation of the target perovskite phase in all synthesized samples. Enhanced redox activity was observed for samples calcined at higher temperatures and for powders prepared by the modified Pechini method. The findings demonstrated that synthesis method and processing parameters significantly influence the redox performance of SLAM materials, with solution-based Pechini synthesis offering enhanced reducibility, while optimized solid-state reaction samples exhibited superior reversibility offering valuable insights for the design of efficient and durable materials for STCH applications.