Role of annealing temperature in synthesis and characterization of Li0.2Zn0.6Fe2.2O4 for photocatalytic dye degradation

Abstract

In this study, we investigate the optimization of lithium zinc ferrite (Li_0.2Zn_0.6Fe_2.2O₄) for enhanced photocatalytic degradation of dyes. Synthesized through sol-gel auto-combustion and subjected to annealing at various temperatures (400 ℃, 500 ℃, and 600 ℃), the nanoferrite underwent comprehensive characterization. XRD confirmed the formation of a cubic structure with a crystallite size ranging from 20 to 30 nm. FTIR elucidated characteristic two prominent M-O bonding bands at 437 cm^-1 and 544 cm^-1, affirming the nanoferrite's structural integrity. XPS revealed the chemical environment of the constituent elements and the oxidation state of iron (Fe⁺³) was confirmed. Morphological analysis conducted via SEM revealed a distinct cubic morphology and average grain size of about 170 nm were calculated. HRTEM provided detailed insights into the crystalline lattice, highlighting the presence of the (311) plane of spinel ferrite with d-spacing 0.256 nm. Additionally, UV-DRS gives Bandgap energy of prepared samples. Notably, annealing at 500 ℃ resulted in exceptional photocatalytic activity, with nearly 90% degradation of RhB achieved after 80 minutes of light irradiation and nearly 85% degradation of MB dye after 140 min. These findings underscore the potential of annealed Li-Zn nanoferrite spinel as a promising photocatalyst for environmental remediation applications.