Investigation of the Pt-Ni-Pb/C ternary alloy catalysts for methanol electrooxidation

This research is aimed to increase the activity of anodic catalysts and thus to lower noble metal loading in anodes for methanol electrooxidation. The Pt-Ni-Pb/C catalysts with different molar compositions were prepared. Their performance were tested by using a glassy carbon disk electrode through cyclic voltammetric curves in a solution of 0.5 mol L-1 CH3OH and 0.5 mot L-1 H2SO4. The performances of Pt-Ni-Pb/C catalyst with optimum composition (the molar ratio of Pt/Ni/Pb is 5:4:1) and Pt/C (E-Tek) were also compared. Their particle sizes and structures were determined by means of X-ray diffraction (XRD). The XRD results show, compared with that of Pt/C, the lattice parameter of Pt-Ni-Pb (5:4:1)/C catalyst decreases, its diffraction peaks are shifted slightly to a higher 20 values. This indicates the formation of an alloy involving the incorporation of Ni and Pb atoms into the fee structure of Pt. The electrochemical measurement shows the activity of Pt-Ni-Pb/C catalyst with an atomic ratio of 5:4:1 for methanol electrooxidation is the best among all different compositions. The activity of Pt-Ni-Pb (5:4:1)/C catalyst is much higher than that of Pt/C (E-Tek). (C) 2008 Elsevier B.V. All rights reserved.