title: Effect of reduction temperature on the preparation and characterization of Pt-Ru nanoparticles on multiwalled carbon nanotubes.
abstract: Carbon nanotubes (CNT) supported platinum-ruthenium (Pt-Ru) catalysts were prepared by impregnation-reduction using an ethanolic solution of H2PtCl6 and RuCl3. The effect of reduction temperatures on particle size, surface area and their relationship to the electrocatalytic activity for methanol oxidation were investigated. Thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD) as well as X-ray photoelectron spectroscopy (XPS) were used for the catalyst characterization. XRD analysis showed that the PtRu/ CNT catalysts possibly consist of separate Pt and Ru phases. XPS analysis showed that the catalysts contain hydrous ruthenium oxide in addition to Pt and Ru metal and oxide species. The electrocatalytic activities of the catalysts were investigated in half-cell experiments using cyclic voltammetry, CO stripping voltammetry, chronoamperometry, and impedance spectroscopy. The results showed that the catalyst reduced at a temperature of 350 degrees C had the largest electrochemical surface area, lowest charge transfer resistance and the highest electrocatalytic activity for methanol oxidation. The superior catalytic activity is discussed based on the presence of appropriate amount of hydrated Ru oxide.
authors.affiliation: Lehrstuhl für Technische Chemie, Analytische Chemie-Elektroanalytik and Sensorik, and Institut für Geologie, Mineralogie and Geophysik, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany. raghuc@iitm.ac.in
authors.forename: Raghuram
authors.initials: R
authors.lastname: Chetty
authors.forename: Wei
authors.initials: W
authors.lastname: Xia
authors.forename: Shankhamala
authors.initials: S
authors.lastname: Kundu
authors.forename: Michael
authors.initials: M
authors.lastname: Bron
authors.forename: Thomas
authors.initials: T
authors.lastname: Reinecke
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schuhmann
authors.forename: Martin
authors.initials: M
authors.lastname: Muhler