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J. Phys. Chem. C 2009, 113, 5460–5466
Enhanced Electrocatalytic Performance of One-Dimensional Metal Nanowires and Arrays Generated via an Ambient, Surfactantless Synthesis Hongjun Zhou,† Wei-ping Zhou,‡ Radoslav R. Adzic,‡ and Stanislaus S. Wong*,†,§ Department of Chemistry, State UniVersity of New York at Stony Brook, Stony Brook, New York 11794-3400, Chemistry Department, BrookhaVen National Laboratory, Building 555, Upton, New York 11973, and Condensed Matter Physics and Materials Sciences Department, BrookhaVen National Laboratory, Building 480, Upton, New York 11973 ReceiVed: December 19, 2008; ReVised Manuscript ReceiVed: February 11, 2009
One-dimensional (1-D) metal (Ag, Au, and Pt) nanowires and their corresponding arrays have been synthesized using an ambient, surfactantless synthesis technique. The potential applicability of such crystalline, highly purified 1-D samples for practical uses was specifically demonstrated in their manifestation as electrocatalysts for an oxygen reduction reaction (ORR). Specifically, Pt 1-D nanostructures possessed a higher ORR activity as compared with that of Pt nanoparticles alone. Ag and Au nanowires also evinced reasonable ORR activity in alkaline solution. Introduction Metallic nanostructures, including Au, Ag, and Pt, have attracted significant attention due to their excellent optical, electrical, and thermal conductivity properties, which are highly relevant for diverse applications such as catalysis, optical imaging, optoelectronics, information storage, fuel-cell technology, and sensing.1-8 Specifically, they strongly absorb and scatter light in the visible region and are relatively stable to oxidation.9 For instance, gold nanowire arrays have been used as sensors for mercury10 and organothiol11 detection in addition to as biosensors for enzyme12 and disease detection.13 Moreover, gold nanotube membranes have been reported as highly selective molecular sieves.14 Ordered silver nanowires have been developed as infrared polarizers15 as well as platforms for surfaceenhanced Raman scattering.16 Platinum nanotubes have been developed as electrodes in ferroelectric semiconductor memory applications due to their chemical stability and low leakage,17 while their nanowire analogues have been considered as components of high-frequency electrochemical resonators.18 As compared with bulk analogues (greater than 1 µm in size) and zero-dimensional nanoparticles (wherein all dimensions are
