Influence of SnO2 Orientation on Electrocatalytic Activities of Pt/SnO2 Model Electrodes for Methanol Oxidation

Tuesday, 3 October 2017: 11:40
National Harbor 14 (Gaylord National Resort and Convention Center)
K. Miyazaki, T. Nagase, T. Fukutsuka, and T. Abe (Graduate School of Engineering, Kyoto University)
As an electrocatalyst in fuel cells, carbon-supported platinum (Pt/C) catalysts are widely used, but there are some problems in the degradation of carbon support and CO poisoning of Pt surface. To mitigate these problems, oxides supports are considered to be an alternative support for Pt catalysts. Oxide supports have some advantages to improve the long-term stability and the CO tolerance of electrocatalysts, but the detailed mechanism of oxide supports has not yet been unveiled. In this study, we fabricated Pt/SnO2 model electrodes with controlling SnO2 crystalline orientation.
Pulsed laser deposition (PLD) technique was used for fabricating the SnO2 support oxides. Single crystals of aluminum and titanium oxides were used as a support for SnO2 thin film fabrication. Platinum nanoparticles were deposited on SnO2 film with the arc plasma deposition. Fabricated model electrodes were characterized with X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. Electrochemical measurements were performed in an aqueous solution with methanol and perchloric acid. CO stripping voltammetry was also carried out to investigate CO tolerance of model electrodes.
XRD patters show SnO2 thin films had surface orientation of (101), (100), and (110). XPS spectra also show the deposited Pt nanoparticles were metallic and had identical positive shift (~ 0.3 eV). The activities for methanol oxidation were in the following order: Pt/SnO2 (101) > Pt/SnO2 (100) > Pt/SnO2 (110). CO stripping voltammograms also showed similar activities for CO oxidation. Detailed influence and mechanism of surface orientation on catalytic activities will be discussed in the meeting.