This paper reports an approach to prepare bimetallic Pt-M(M=Fe，Co，and Ni)nanoalloys as electrocatalysts and examines their electrochemical activities in 1M sulfuric acid. The approach consists of chemical oxidation of carbon nanotubes(CNTs)，two-step refluxing，and subsequent thermal reduction in hydrogen atmosphere. Three bimetallic pairs of Pt-M catalysts are found towell deposit onto CNT surface，forming Pt-M/CNT composites. The electrochemial behavior ofPt–M/CNT electrodes was investigated in 1M H2SO4 by using cyclic voltammetry（CV) and acelectrochemical impedance spectroscopy. The active surface coverage(=electrochemical surfacearea/geometric surface area) of Pt-M catalysts is significantly enhanced；I.e.，Pt-Co(89.2%)>Pt-Ni(85.5%)>Pt-Fe(80.3%)>Pt(27.7%). This enhancement of electrochemical activity can beattributed to the fact that the introduction of Co and Ni may reduce the required potential for water electrolysis and thus the associated carbon oxidation，thus contributing to hydrogen adsorption. Equivalent circuit analysis indicates that(ⅰ)charge transfer resistance account for the majorproportion of the equivalent serial resistance of Pt-M/CNT electrodes，and(ⅱ)Pt-Co and Pt-Ni catalysts not only improve the electrochemical capacitance but also lower the equivalent serial resistance. The results shed some lights on how use of Pt-M/CNT composite would be a promising electrocatalyst for high-performance fuel cell applications.
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