Novel NiFe/Si/Au magnetic nanocatalyst: Biogenic synthesis, efficient and reusable catalyst with enhanced visible light photocatalytic degradation and antibacterial activity

The aim of this paper is to biosynthesize NiFe₂O₄/SiO₂/Au (NiFe/Si/Au) magnetic nanocatalyst using the sonochemical method. This is the first study to synthesize this compound using this method. To obtain optimum morphology and size of products, the synthesis was performed in the presence of polyvinylpyrrolidone, maltose, glucose, and fructose as capping agents and Crataegus pentagyna leaf extract and NaBH4 as reducing agents. Vibrating-sample magnetometer, field-emission scanning electron microscopy, Fourier-transform infrared, transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and differential reflectance spectroscopy techniques were performed to confirm the preparation of magnetic products. The as-synthesized magnetic samples were used to enhance the photocatalytic degradation and antibacterial activity. The NiFe/Si/Au nanocatalysts exhibited an excellent photocatalytic activity by degradation of rhodamine b, methylene blue, and erythrosine as organic contaminants under ultraviolet and visible light irradiation. The degradation curves illustrate that the degradation of anionic dyes is more than that of cationic dyes. In addition, antibacterial activity of as-prepared nanocatalyst against seven bacterial species was investigated. Because of their antibacterial effects, as-synthesized products show a high antibacterial activity against various bacteria. Consequently, the NiFe/Si/Au nanocatalysts with high antibacterial activity and excellent potential photocatalyst activity can be used in environmental and medical sciences for wastewater treatment.