Green synthesis of SrFe12O19@Ag and SrFe12O19@Au as magnetic plasmonic nanocomposites with high photocatalytic performance for degradation of organic pollutants

Abstract

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 SrFe₁₂O₁₉@Ag, SrFe₁₂O₁₉@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 SrFe₁₂O₁₉@Ag and SrFe₁₂O₁₉@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.

Keywords: Anthraquinone; Azo dye; Hexaferrite; Noble metals; Photodegradation; Sol-gel auto-combustion.