Synthesis and Photocatalytic Performance of Manganese‐Based Nanocomposites for the Degradation of Imidacloprid Under UV Light

ABSTRACT The extensive use of the neonicotinoid pesticide imidacloprid poses serious environmental concerns due to its persistence and toxicity in aquatic‐systems. This study reports the photocatalytic degradation of commercially available Confidor (17% imidacloprid) under UV irradiation using a Dy (0.15) Mo (0.15) @MnFe 2 O 4 nanocomposite. The photocatalyst was synthesized via the coprecipitation‐method followed by calcination. and characterized using X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM)‐EDX, UV‐visible, photoluminescence (PL), and transient photoluminescence (TRPL) analyses. XRD confirmed the formation of a cubic‐spinel‐structure, while SEM images revealed uniform, spherical‐nanoparticles of approximately 66 nm. The MnFe 2 O 4 provides magnetic and structural‐stability, whereas the Dy–Mo enhances light absorption, charge separation, and surface reactivity. The reduced long‐lived lifetime (0.81 ns) and average lifetime (219 ns) of DyMo@MnFe 2 O 4 are attributed to the rapid charge‐transfer between heterojunction and suppressed recombination due to the Dy and Mo doping in MnFe 2 O 4 . Photocatalytic‐degradation reached 87% within 60 min at a pH of 9, with an apparent rate constant ( k app ) of 0.031 min −1 , following Langmuir–Hinshelwood kinetics ( K = 0.018 mM −1 ; κ = 2.5 mM min −1 ; R 2 = 0.991). A 75% reduction in total organic carbon confirmed effective mineralization, and the catalyst retained ∼74% activity after five reuse cycles, demonstrating high stability. These findings confirm DyMo@MnFe 2 O 4 as an efficient and reusable photocatalyst for pesticide degradation in water.