Quantum Confined One-Dimensional Lepidocrocite TiO2–Assisted In Situ Synthesis of ZIF-8 MOF: Hierarchical Porous Nanocomposites Exhibit Improved Li-ion Transport

Abstract One-dimensional (1D) nanostructured materials offer distinctive physical and chemical properties suitable for advanced energy applications. Among these, 1D lepidocrocite-type TiO2 (1DL), recently discovered, has shown potential in batteries, water splitting, wastewater treatment, and polymer composites, among others. In this study, we report on the combination of 1DL with an in situ formed metal–organic framework (MOF), specifically ZIF-8, to produce a hierarchically porous ZIF-8/1DL composite. X-ray diffraction (XRD) confirms the successful in situ formation of ZIF-8 in the presence of 1DL. In the composite, the average ZIF-8 size is ∼30 nm, that is smaller than that observed in conventional bulk syntheses that typically yield micron-scale crystals. Zeta-potential measurements indicate electrostatic interactions between positively charged ZIF-8 particles and negatively charged 1DL, which stabilize the composite. Transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) mapping show a relatively uniform distribution of ZIF-8 on 1DL surfaces. Nitrogen adsorption–desorption analyses reveal a substantial increase in specific surface area from 20 m2 g–1 for 1DL to 501 m2 g–1 for ZIF-8/1DL, together with the coexistence of micropores and newly generated mesopores. Electrochemical evaluation in lithium–sulfur (Li–S) batteries indicates enhanced Li-ion transport in the composite compared with 1DL alone. These findings highlight the utility of 1DL as a structural framework for MOF-based nanocomposites and provide a pathway to hierarchical designs for energy-storage applications.