Highly loaded silver nanoparticle-modified monodispersed polystyrene composite microspheres (PS/Ag) for rapid catalytic reduction of methylene blue

In this research, monodispersed polystyrene (PS) microspheres were prepared by dispersion polymerization. PS microspheres decorated with silver nanoparticles (PS/Ag composite microspheres) were synthesized by a modified chemical plating method with water as the synthesis medium. The microspheres at each stage were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), field-emission scanning electron microscopy (FESEM), and energy-dispersive spectrometer (EDS). The reduction of methylene blue (MB) was carried out with PS/Ag composite microspheres as a catalyst and NaBH 4 as a reducing agent. The results showed that the MB dye was reduced to colorless within 180 s. The reduction of the MB dye followed pseudo-first-order kinetics with an apparent rate constant (K app ) value of 0.01425 s −1 . Control experiments were also carried out by adding microspheres from each chemical plating pretreatment stage to the MB, without PS/Ag composite microspheres. The catalytic activity of the PS/Ag composite microspheres was high after five consecutive cycles of recovery, showing promising reusability. The catalytic activity of the prepared PS/Ag catalysts was superior to other catalysts for the reduction of MB.