RESUMEN
We recently found that [Pt17(CO)12(PPh3)8]z (Pt = platinum; CO = carbon monoxide; PPh3 = triphenylphosphine; z = 1+ or 2+) is a Pt nanocluster (Pt NC) that can be synthesized with atomic precision in air. The present study demonstrates that it is possible to prepare a Pt17-supported carbon black (CB) catalyst (Pt17/CB) with 2.1 times higher oxygen reduction reaction (ORR) activity than commercial Pt nanoparticles/CB by the adsorption of [Pt17(CO)12(PPh3)8]z onto CB and subsequent calcination of the catalyst. Density functional theory calculation strongly suggests that the high ORR activity of Pt17/CB originates from the surface Pt atoms that have an electronic structure appropriate for the progress of ORR. These results are expected to provide design guidelines for the fabrication of highly active ORR catalysts using Pt NCs with a diameter of about 1 nm and thereby enabling the use of reduced amounts of Pt in polymer electrolyte fuel cells.
RESUMEN
The improvement of oxygen reduction reaction (ORR) catalysts is essential before polymer electrolyte fuel cells can be used widely. To this end, we established a simple method for the size-selective synthesis of a series of ligand-protected platinum nanoclusters with â¼1 nm particle size (Ptn NCs; n = â¼35, â¼51, and â¼66) and narrow size distribution (±â¼4 Pt atoms) under atmospheric conditions. Using this method, each ligand-protected â¼1 nm Pt NC was obtained in a relatively high yield (nearly 80% for Ptâ¼66). We succeeded in adsorbing each ligand-protected â¼1 nm Pt NC on carbon black (CB) and then removing most of the ligands from the surface of the Pt NCs via calcination while maintaining the original size. The obtained Ptâ¼35/CB, Ptâ¼51/CB, and Ptâ¼66/CB exhibited ORR mass activities that were 1.6, 2.1, and 1.6 times higher, respectively, than that of commercial CB supported-Pt nanoparticles, and also display high durability.