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

Abstract

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 NaBH4 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 (Kapp) 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.

Janus Hemispheres through Controlled Polymerization-Induced Phase Separations within Wax Droplets

“…The ζ-potential of the PAM/PS Janus hemisphere became more positive to −13.0 mV from the original −21.6 mV of the PS hemisphere, which was located at −16.5 and −17.5 mV for the PAH/PS Janus hemisphere and the PVIm/PS Janus hemisphere, respectively (Figure S1b). The original PS hemisphere is negatively charged similar to the reported PS microspheres, while three Janus hemispheres become positive due to the modified flat surface. Moreover, all hemispheres showed a narrow size dispersion with the size increasing from about 1190 nm of the PS hemisphere to 1230 nm of the PAM/PS Janus hemisphere, to 1500 nm of the PAH/PS Janus hemisphere, and to 1380 nm of the PVIm/PS Janus hemisphere (Figure S1c).…”