Synthesis, characterization, and reaction studies of a PVP-capped platinum nanocatalyst immobilized on silica.

An immobilized platinum nanocatalyst was prepared by first functionalizing the surface of activated silica with poly(vinylpyrrolidone) (PVP) and then reducing encapsulated platinum ions in the presence of these functionalized supports to form nanoparticles. Surface functionalization was monitored by infrared spectroscopy and surface area measurements, and the resulting nanocatalyst was characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD). Platinum nanoparticle size was determined to be approximately 5 nm based on TEM and XRD measurements. Catalytic activity of this material for the hydrogenation of cyclohexanone was found to be greater than that of unsupported colloidal PVP-capped platinum nanocatalysts. In addition, the immobilized nanocatalyst displayed no change in activity after being recycled. Taken together, these results clearly indicate advantages in the design of catalytic materials with desired properties.