Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (10): 1132-1137.doi: 10.3866/PKU.WHXB20051014

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Electrooxidation of CO Adsorbed on PtMo/C Catalyst:Effect of Catalyst Preparation

LI Li; XU Bo-qing   

  1. Innovative Catalysis Program, Key Lab of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084
  • Received:2005-01-26 Revised:2005-05-16 Published:2005-10-15
  • Contact: XU Bo-qing

Abstract: PtMo/C electrocatalysts were prepared by three different preparation methods, namely 1) chemical reduction with oxalic acid, 2) colloidal precursor, and 3) Adams method respectively. TEM, XRD and CO-stripping in 0.5 mol•L-1 H2SO4 solution were performed to characterize the particle size distribution and electrocatalytic property of the prepared samples. PtMo particles from the colloidal preparation were ca. 5 nm in sizes and were well dispersed on the carbon support. The preparation by Adams method produced aggregated larger PtMo particles with sizes up to tens of nanometers. The sizes and morphology of PtMo particles from the chemical reduction method were found in between those from the colloidal preparation and the Adams method. The electro- oxidation of CO adsorbed on all of the three PtMo/C catalysts showed two distinct peaks, one at very low potential (ca. 0.15 V) and the other at a potential (ca. 0.77 V) very close to that over the conventional Pt/C catalyst. Moreover, the PtMo/C catalyst obtained from the colloidal preparation exhibited, among the three catalysts of this study, the highest electrocatalytic activity for the oxidation of CO. Although the electrochemical surface area of this PtMo/C catalyst was lower in comparison with the conventional PtRu/C catalyst, the removal percentage of CO at low oxidation potentials(0.15~0.50 V) was found to be much higher. Therefore, the presence of Mo component in the catalysts promoted the electro-oxidation of weakly adsorbed CO, whereas it showed little effect on the oxidation of strongly adsorbed CO.

Key words: PEMFCs, CO tolerance catalysts, PtMo/C, PtRu/C, CO electooxidation