Preparation and photocatalytic degradation of ZnO/Fe₃O₄/GO heterojunction via synergistic electron-hole separation

In this work, a ternary ZnO/Fe₃O₄/GO nanocomposite was synthesized via the co-precipitation method and characterized to evaluate its potential photocatalytic activity for the degradation of methylene blue under standard conditions. The structural, morphological, and surface chemical features were investigated using XRD, SEM-EDS, Raman, and XPS analyses, confirming the successful integration and strong interfacial interactions among the ZnO, Fe₃O₄, and GO phases. The nanocomposite exhibited enhanced e + /h − separation via GO-mediated charge transfer, which explains the high 86 % achieved after 180 min of UV irradiation, followed by 60 min dark adsorption–desorption equilibrium step (total experiment duration of 210 min) under standard laboratory conditions, following pseudo-first-order kinetics. Unlike non-recoverable catalysts (e.g., pure ZnO) or toxic alternatives (e.g., CdS-based composites), this ternary system uniquely combines magnetic separation (Fe₃O₄) with GO-enhanced stability, achieving 77 % reusability over five cycles, higher than reported ternary composites. These findings suggest that the ZnO/Fe₃O₄/GO nanocomposite is a promising, magnetically separable photocatalyst for removing organic contaminants from water. Schematic Diagram via Synergistic e − /h + Separation. • ZnO/Fe₃O₄/GO nanocomposite synthesized via a simple co-precipitation method. • XRD, Raman, SEM-EDS, UV–Vis, and XPS confirm strong interfacial bonding among components. • Achieved 86% photocatalytic degradation and 77% recyclability after magnetici recovery.