A green sol-gel route to Fe3O4@TiO2−CuO photocatalysts with structural stability, visible-light activity, and magnetic recoverability

Abstract

In this work, we present the synthesis of a multifunctional Fe3O4@TiO2−CuO photocatalyst, integrating Magonia pubescens plant extract and urea-assisted pH modulation. The as-prepared composite exhibits outstanding visible-light photocatalytic performance, achieving 75% degradation of rhodamine B (RhB, 15 ppm) after 5 h under 100 W LED irradiation and retaining more than 45% activity across four reuse cycles enabled by simple magnetic recovery. Notably, urea-assisted synthesis reduces iron leaching by ∼50%, preserving magnetic integrity and enabling efficient catalyst separation. Comprehensive structural, morphological, and surface analyses (TEM, XRD, XPS, XRF, VSM, ICP, GC−MS) confirm the formation of a robust, magnetically recoverable hybrid with a narrowed band gap of 1.65 eV and enhanced stability. GC−MS analysis revealed progressive mineralization of RhB into lowmolecular-weight intermediates.