Effect of Structure of Carbon-Supported PtRu Electrocatalysts on the Electrochemical Oxidation of Methanol

Carbon‐supported binary PtRu electrocatalysts were prepared by coimpregnation using ethanolic solutions of as the Pt source, various Ru sources [ , , and ], and carbon black by thermal decomposition under reducing conditions, and their structure, morphology, and electrocatalytic properties were investigated. X‐ray diffraction analysis and high resolution scanning electron microscopy indicated that the use of Cl‐free Ru sources, i.e. , or afforded highly dispersed and uniform PtRu nanoparticles. Surface area measurements conducted by electro‐oxidation of preadsorbed carbon monoxide indicated that the use of as the Ru source yielded high surface area catalysts. In terms of the surface‐area specific current density (current density normalized by the specific surface area of PtRu metal obtained from preadsorbed CO electro‐oxidation measurements), the electrocatalytic activity of and were equal. PtRu/C electrocatalysts prepared from ethanolic solutions of resulted in high mass‐specific activity toward methanol oxidation, with mass‐specific current density as high as at 500 mV. The efficiency of PtRu/C electrodes is discussed based on the significance of the use of Cl‐free Ru sources. © 2000 The Electrochemical Society. All rights reserved.