Photocatalytic synthesis of Se nanoparticles using polyoxometalates

Selenium nanoparticles are formed upon photolysis of solutions of (propan-2-ol/POM/Se(IV)), where polyoxometalate (POM) is either PW12O403− or SiW12O404−. Propan-2-ol serves as sacrificial reagent for the photoformation of 1-equivalent reduced blue polyoxometalate, POM(e), which further reacts with Se(IV) to produce selenium nanoparticles. POM serves both as relay for the transfer of electrons from propan-2-ol to Se(IV) and stabilizer for the nanoparticles. Changing the ionic strength from 0 to 0.025 and 0.05 M, results in the formation of gradually larger nanoparticles 40, 60 and 90 nm, respectively. Increase of the initial concentration of SiW12O404−, from 2 to 4 and 10 × 10−3 M, results in the formation of gradually smaller nanoparticles, 110, 80 and 60 nm, respectively.