In this work, we report the synthesis of fragmented lignin (FL) assisted zinc oxide (ZnO) and titanium oxide (TiO₂) nanocomposites. The fragmented lignin synthesized from biomass (sugarcane bagasse) was used as a template to generate the morphology and crystallite structure of metal oxide nanomaterial. The nanocomposites were synthesized by a simple precipitation method, wherein fragmented lignin is used in alkaline medium as a template. X-ray diffraction (XRD) analysis shows the phase formation of hexagonal wurtzite ZnO and mixed phase formation of TiO₂ as rutile and anatase. The morphology was studied by using field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM). The FE-SEM of pristine ZnO nanocomposites showed a cluster of particles whereas FL–ZnO NPs showed self-aligned nanoparticles in the form of rod shaped having average size 30–70 nm. Pristine TiO₂ nanoparticles showed clusters of particles and FL–TiO₂ nanocomposites showed well crystalline 41nm size nanocomposites. The FL acts as a surfactant which restrict the cluster formations. The band gap determined by diffuse reflectance spectra is 3.10 eV and 3.20 eV for FL–ZnO and FL–TiO₂ nanocomposites, respectively. Photoluminescence spectra of both nanocomposites showed structural defects in the visible region. Further, the antimicrobial activity of pristine ZnO and TiO₂ nanoparticles, and FL–ZnO and FL–TiO₂ nanocomposites against Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923) were studied under UV-A (315-400 nm) (8W) for 30min.

The three-dimensional hierarchical SrS/Bi₂S₃ heterostructures were synthesized by a template-free single-step hydrothermal method. The structural and morphological studies revealed the formation of a single crystalline orthorhombic heterostructure with rod-like morphologies possessing a high aspect ratio. The field emission properties of SrS/Bi₂S₃ nanorods were investigated. J–E and the Fowler–Nordheim (F–N) plot, as well as long-term field emission (FE) stability, were studied. SrS/Bi₂S₃ nanoflowers have enhanced the FE properties more than the virgin Bi₂S₃. The observed values of the re-producible turn-on field for SrS/Bi₂S₃ defined to draw an emission current density of ca. 1 µA/cm² were found to be ca. 2.50 V/µm, and of the threshold field to draw a current density of ca. 10 µA/cm² were found to be ca. 3.00 V/µm (without visible light illumination). A maximum emission current density of ca. 527 μA/cm² was drawn without light and a current density of ca. 1078 μA/cm² with light, which is higher than that of pristine Bi₂S₃.