The composite materials containing platinum nanoparticles deposited onto carbon support are most promising electrocatalysts for the low-temperature fuel cells. However, pure Pt catalysts exhibit degradation during the operation of fuel cells as well as propensity to agglomeration of catalysts particles making their application rather difficult. These problems can be solved by using Pt alloys with Co, Ni, etc. The purpose of the present work is investigation of structural and microstructural parameters of Pt₃Co/C catalysts.

The investigated Pt₃Co/C electrocatalysts were prepared onto a high surface area carbon powder (Timrex HSAG-300) by chemical reduction of the precursors using NaBH₄ [1]. The water/ethyleneglycol ratio in the solvent was 1:5, 1:1 and 5:1. For estimation of corrosion and aggregate stability, as prepared samples were treated in 1M H₂SO₄ at 80^oC for 1 h. X-ray diffraction measurements were carried out at SNBL ESRF.

The analysis of X-ray powder patterns of all samples has shown following: 1) the average particle size D of synthesized Pt₃Co/C samples vary from 3 up to 4,9 nm; 2) increasing of concentration of an organic component in the solvent causes decreasing of the average particle size; 2) particle size increases by 0,8-1 nm and grain size distribution (GSD) become wider after treatment by solution H₂SO₄; 4) the narrowest GSD is observed at 1:5 ratio of the solvent; 5) the lattice parameter as a function of particle size shows nonlinear dependence both for untreated and treated by H₂SO₄ solution samples.

Increasing of anisotropic line broadening with increasing of grain size was observed for all samples studied. Nonequivalent size of particles along different crystallographic directions is the reasons of the observed behavior. The analysis of roentgenograms by means of FullProf has allowed to determine the typical shape of Pt₃Co catalyst nanoparticle. Figure illustrates SEM image (left) and shape determined from X-ray diffraction pattern (right)

1. F.H.B. Lima et al. / Electrochimica Acta 52 (2006) 385–393

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/15269 must be provided.