Size-controlled synthesis and characterization of polyvinyl alcohol-coated platinum nanoparticles: role of particle size and capping polymer on the electrocatalytic activity

Electrocatalytically active polymer-platinum nanocomposites have been synthesized in one pot by refluxing an aqueous solution consisting of chloroplatinic acid, PVA and formic acid. The as-synthesized platinum nanoparticles have large variations in their average size from 2.9 to 60.0 nm. The size of the nanoparticles is tuned by changing the concentration of the stabilizer as well as that of the reducing agent. In addition, the particle size is also controlled by varying the reflux time for a particular precursor solution. In this study, the nanoparticles have been characterized by UV-visible spectroscopy, XRD, TEM, FE-SEM and cyclic voltammetry. The study also shows that nanoparticles have size-dependent electrocatalytic behavior for anodic oxidation of alkaline methanol when the particle surface bears almost the same concentration of PVA. But the expected catalytic activity based on the particle size is found to alter when the nanoparticles possess a different surface concentration of PVA.