Inorganic materials with layered architectures are made up of stacked atomic or molecular layers held together by weak van der Waals interactions. Examples of such materials include layered perovskites, clays, MXenes, transition metal dichalcogenides, layered double hydroxides, and carbon-based layered materials. The intercalation of various guest species (e.g., nanoparticles, molecules, polymer chains) into lamellar inorganic compounds is an effective strategy for creating multifunctional materials with enhanced physical and chemical properties relative to those of the parent compounds. Exfoliation of layered nanostructures into single nanosheets yields soft materials with distinct features. The intercalation process is affected by several critical factors, including interlayer distance, guest orientation in the interlayer space, and/or layer rigidity. Tailoring these factors enables the creation of high-performance intercalated materials with applications across energy storage, electronic devices, sensors, catalysis, and nanotechnology.

Herein, we report a soft chemical approach to intercalating copper species into the RbLaTa₂O₇ layered perovskite tantalate involving a copper halide precursor at a mild temperature. Both unmodified and (CuCl)⁺-intercalated layered perovskite were characterized using multiple techniques to assess structural, optoelectronic, and morphological changes. The shifting of the (001) diffraction line confirmed the successful insertion of (CuCl)⁺ species in between the perovskite layers. The FTIR technique validated structural modifications in the materials. UV-Vis spectroscopy demonstrated a decrease in the band gap of the (CuCl)⁺-intercalated layered tantalate, thereby enabling visible-light absorption. Preliminary photocatalytic performance evaluations indicate that (CuCl)⁺-based perovskite exhibits promising activity for phenol degradation, serving as an effective catalyst for environmental applications.

Acknowledgements. The authors thank the Inter-academic exchange project between the Romanian Academy and the Hungarian Academy of Sciences, Nr. Reg. A.R. 4389/25.09.2025; period: 2026 – 2028.