A Simplistic Preparation of Gold-Doped Magnetic Hybrid Nanoparticles as Recyclable Nanocatalysts for the Hydrogenation of Nitroarenes as well as Surface-enhanced Raman Scattering Substrates

Magnetic nanomaterials have garnered significant attention for their multifunctional properties. In this study, gold-doped magnetic hybrid nanoparticles (AuMNPs) were synthesized through a simple and efficient spontaneous redox process. The resulting AuMNPs were characterized using transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), zeta potential analysis, and X-ray spectroscopy. Owing to their magnetic properties, the AuMNPs function as quasi-homogeneous nanocatalysts that can be easily separated and reused. The catalytic performance was evaluated through the hydrogenation of o-nitroaniline (o-NA), achieving over 99% conversion within 3 minutes with an apparent rate constant of 0.0392 s⁻¹. Reaction efficiency was influenced by pH, temperature, and catalyst loading. In addition to catalysis, the AuMNPs served as effective substrates for surface-enhanced Raman scattering (SERS), enabling sensitive detection of p-aminothiophenol with a detection limit of 50 nM. Overall, the AuMNPs prepared via this facile route combine high catalytic activity, magnetic recyclability, and SERS sensitivity. These attributes highlight their potential for industrial catalysis and molecular detection, as well as for fundamental studies on reaction mechanisms.