"Anisotropic nanomaterials: A new type of electrocatalyst"
Who: Dr. Mariana Chirea, Universidade de Vigo, Vigo, Spain
Place: nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
Date: Thursday, 2 October 2014, 11:00
Host: Alexander Bittner
Dendrite, star-shaped, flower-like and other anisotropic morphologies of Pt, Au or Pd nanostructures are interesting in terms of potential catalytic applications because they contain surfaces with high-index crystal facets, which allow a relative abundance of active corner and edge sites.(1-3) Such branched morphologies typically possess a high surface area, which in general helps to increase the catalytic activity of nanoscale structures. Pt dendrites of various porosities and Pt-Au heterostructures were used as catalysts for ethanol oxidation reaction. Sensing, selectivity, cycleability and great tolerance toward poisoning were demonstrated by cyclic voltammetry measurements. Electron tomography revealed different crystalline orientations of nanocrystallites in the nanodendrites as well as twin defects in spherical Au particles epitaxially grown on the dendrites. The high surface area of the dendrites (up to 22 m2 g-1) was confirmed by BET measurements, while X-ray diffraction confirmed the abundance of high-index facets in the face-centred-cubic crystal structure of Pt. The catalytic response of the nanostructures reveals great potential for direct ethanol fuel cells (DEFCs) applications.
(1) S. Mourdikoudis et al. Nanoscale, 2013. 5, 4776-4784
(2) S. Barbosa et al. Langmuir, 2010, 26 (18), 14943-14950
(3) S. Guo et al. ACS Nano 2010, 4 (1), 547-555