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论文类型：期刊论文

发表时间：2010-05-01

发表刊物：ELECTROCHIMICA ACTA

收录刊物：SCIE、EI

卷号：55

期号：13

页面范围：4217-4221

ISSN号：0013-4686

关键字：Fuel cell; Alloy catalyst; Palladium; Formic acid oxidation; Carbon nanotubes

摘要：Pt, Pd and PtxPdy alloy nanoparticles (Pt1Pd1, Pt1Pd3, atomic ratio of Pt to Pd is 1:1.1:3, respectively) supported on carbon nanotube (CNT) with high and uniform dispersion were prepared by a modified ethylene glycol method. Transmission electron microscopy images show that small Pt and PtxPdy nanoparticles are homogeneously dispersed on the outer walls of CNT, while Pd nanoparticles have some aggregations and comparatively larger particle size. The average particle sizes of Pt/CNT, Pt1Pd1/CNT, Pt1Pd3/CNT and Pd/CNT obtained from the Pt/Pd (2 2 0) diffraction peaks in the X-ray diffraction patterns are 2.0, 2.4, 3.1 and 5.4 nm, respectively. With increasing Pd amount of the catalysts, the mass activity of formic acid oxidation reaction (FAOR) on the CNT supported catalysts increases in both cyclic voltammetry (CV) and chronoamperometry (CA) tests, although the particle size gets larger (thus, the relative surface area gets smaller). The CV study indicates a 'direct oxidation pathway' of FAOR occurred on the Pd surface, while on the Pt surface, the FAOR goes through 'COads intermediate pathway'. Pd/CNT demonstrates 7 times better FAOR mass activity than Pt/CNT (2.3 mA/mgPd vs. 0.33 mA/mgPt) at an applied potential of 0.27 V (vs. RHE) in the CA test. (C) 2010 Elsevier Ltd. All rights reserved.