Synergistic effects of Fe2O3 and carbonization on the morphological and optical properties of lignin/PVA composite films

This study examines the structural and optical characteristics of lignin/polyvinyl alcohol (PVA) composite films, with a particular emphasis on the influence of Fe2O3 incorporation and carbonization under a nitrogen atmosphere. Field-emission scanning electron microscopy (FE-SEM) analysis demonstrated that variations in Fe₂O₃ concentration induce significant morphological changes, transitioning from nanorod formations to fibrous structures as the concentration increases. The carbonization process enhanced the structural stability and porosity of the films, facilitating the integration of Fe2O3 nanoparticles into the carbonized matrix. Raman spectroscopy revealed shifts in the graphitic (G-band) and disordered (D-band) carbon structures, indicating enhanced graphitization at higher Fe2O3 concentrations. Photoluminescence studies identified emission peaks at 605 nm, 750 nm, and 857 nm, corresponding to carbon dots, defect states, and extended sp²-hybridized carbon networks, respectively. The incorporation of Fe2O3 introduced additional peaks, signifying π-π* transitions and Fe3+-related defects. These findings underscore the synergistic role of Fe2O3 and carbonization in modulating the material’s properties, rendering it suitable for advanced applications in sensors, supercapacitors, and catalysis. carbonization in modulating the material’s properties, rendering it suitable for advanced applications in sensors, supercapacitors, and catalysis.