Micelle Directed Synthesis of Polyoxometalate Nanoparticles and Their Improved Catalytic Activity for the Aerobic Oxidation of Sulfides

Micelle directed polyoxometalate nanoparticles were synthesized by depositing H3+xPVxMo12-xO40 (x = 0, 2) by precipitation on micelles prepared from cesium dodecyl sulfate. The cryo-TEM image showed particles of about approximately 10 nm roughly consistent with the particle size computed from an idealized model. HRTEM coupled with EELS imaging to map the distribution of the elements also supported the formation of micelle directed polyoxometalate nanoparticles. In the aerobic oxidation of various sulfides to sulfoxides and sulfones, the clustered polyoxometalate assemblies supported on hydrophilic silica showed significantly higher catalytic activity versus that of nonclustered assemblies.