| Abstract Scope |
Ruddlesden-Popper (RP) oxides, with layered Srn+1TinO3n+1 structures, provide a model platform to explore anisotropic structure-property relationships arising from reduced dimensionality and a flexible anion sublattice. In this work, we focus on Sr-Ti-based RP systems, specifically n = 1 (Sr2TiO4) and n = 2 (Sr3Ti2O7), to understand how structural dimensionality governs functional response. Low-temperature topochemical reactions enable selective modification of the anion sublattice while preserving the parent framework, allowing controlled tuning of lattice distortions, interlayer spacing, and electronic structure. Topochemical fluorination and subsequent reduction induce anisotropic structural responses along the c-axis, accompanied by changes in optical absorption and charge transport. These modifications are reflected in the photocatalytic hydrogen evolution behavior, with improved hydrogen generation compared to the parent oxides, highlighting the role of anion engineering and dimensionality. This low-temperature topochemical "chemie-douce" approach provides a pathway to design metastable layered materials with tunable structure–property relationships for energy-relevant applications. |