Platinum nanoparticles synthesized via green nanotechnology

Abstract

Platinum nanostructures such as colloidal platinum nanoparticles, supported platinum nanopartcles heterogeneous catalyst, and platinum pentagonal hollow fibers were successfully synthesized using green synthesis approach. The green reagent, soluble starch shows the efficiency as a reducing and a stabiizing agent under alkaline treatment. The in situ generated reducing species (intermediates of starch degradation) could completely reduce platinum ions and sufficiently stabilize the obtained platinum nanoparticles (Pt NPs) of uniform particle size (2-4 nm). The developed green approach is further used for preparaton of hydrotalcite-supported platinum nanoparticles catalyst (Pt NPs/HT). Their catalytic activity is evaluated for selective oxidation of glycerol in a base-free aqueous soluton using molecular oxygen as an oxidant. They show a high selectivity towards glyceric acid. In addition, the catalyst could be recycled at least for three times. Platinum pentagonal hollow wire could be obtained by the galvanic displacement with silver microfibers. Prior, the extra-long silver microfibers with aspect ratio as high as 7500 were synthesized galvanically from silver nitrate and a commercial aluminum foil. The enveloped of the silver fibers sacrificed template creates unique platinum pentagonal hollow fibers. The hallow fibers still retain the long fiber structure of the original template even after the removal of silver chloride precipitates. These hollow fibers with nanometer thick wall might have a great potential for applications as catalyst.