Riley oxidation: A forgotten name reaction for synthesis of selenium nanoparticles

A simple wet chemical method, involving reaction of acetone with selenium dioxide, has been developed, to synthesize polyvinyl alcohol-stabilized selenium nanoparticles. The method is capable of producing nanoparticles in the size range of about 100–300 nm, under ambient conditions. The synthesized nanoparticles can be separated easily from the aqueous sols by a high-speed centrifuge, and can be re-dispersed in aqueous medium by a sonicator. The effect of concentrations of selenium dioxide, acetone and PVA on the size of the selenium nanoparticles has been studied. The size of the selenium nanoparticles has been found to increase with increase in the reaction time as well as the concentration of selenium dioxide, while it decreases with increase in the concentration of the stabilizer, PVA. The synthesized selenium nanoparticles have been characterized by UV–visible optical absorption spectroscopy, X-ray diffraction, energy dispersive X-ray analysis, differential scanning calorimetry, atomic force microscopy, scanning electron microscopy and transmission electron microscopy techniques.