Electrochemical observation of ligand effects on oxygen reduction at ligand-stabilized Pt nanoparticle electrocatalysts

摘要

We investigate the effect of triphenylphosphine triphosphonate, TPPTP, on the electrocatalytic activity for the oxygen reduction reaction (ORR) at ligand-stabilized Pt nanoparticles (Pt-2.1 nm-TPPTP). The Pt-2.1 nm-TPPTP catalyst supported on Vulcan carbon (VC) (Pt-2.1 mm-TPPTP/VC) adsorbs and desorbs oxygen +40 mV vs the potential for bare Pt nanoparticles supported on VC (Pt-2.4 nm/VC), as measured by cyclic voltammetry in Ar-saturated 0.1 M HClO4. The area-specific ORR activity (i(s)) of Pt in the Pt-2.1-TPPTP/VC catalyst is similar to 22% higher than that of Pt-2.4 nm/VC, as measured by rotating disk electrode voltammetry. These results suggest that the TPPTP ligand weakens the Pt-O bond, resulting in the observed kinetic enhancement of the ORR.