Green synthesis of SrFeO@Ag and SrFeO@Au as magnetic plasmonic nanocomposites with high photocatalytic performance for degradation of organic pollutants.

Magnetic-plasmonic nanocomposites are suitable candidates for photocatalytic activity due to both optical and magnetic properties. So initially, we synthesized strontium hexaferrite nanoparticles (NPs) by three different methods: microwave, sol-gel Pechini, sol-gel auto-combustion, and SrFeO@Ag, SrFeO@Au core-shell by ultrasound-assisted auto-combustion in the presence of beetroot juice. X-Ray Powder Diffraction (XRD), Fourier Transform Infrared (FT-IR), Energy Dispersive X-Ray (EDX), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET), Diffuse Reflectance Spectroscopy (DRS), and Vibrating Sample Magnetometer (VSM) analyses were utilized to examine their purity, morphology, optical and magnetic properties. The nanoproducts were applied as photocatalysts to degrade the anionic dyes with different chromophores under various visible light sources within 2 h. Among different dyes (mono-azo, diazo, anthraquinone, and triaryl methane), Eosin as a triaryl methane dye had the maximum degradation by SrFeO@Ag and SrFeO@Au, which are about 95.9%, 93.88%, respectively. Indeed, produced surface plasmon resonance (SPR) electrons by the noble metals facilitate the formation of active radicals to destruct the dyes.