title: Electrochemical Behavior of TiO(x)C(y) as Catalyst Support for Direct Ethanol Fuel Cells at Intermediate Temperature: From Planar Systems to Powders.
abstract: To achieve complete oxidation of ethanol (EOR) to CO2, higher operating temperatures (often called intermediate-T, 150-200 °C) and appropriate catalysts are required. We examine here titanium oxycarbide (hereafter TiOxCy) as a possible alternative to standard carbon-based supports to enhance the stability of the catalyst/support assembly at intermediate-T. To test this material as electrocatalyst support, a systematic study of its behavior under electrochemical conditions was carried out. To have a clear description of the chemical changes of TiOxCy induced by electrochemical polarization of the material, a special setup that allows the combination of X-ray photoelectron spectroscopy and electrochemical measurements was used. Subsequently, an electrochemical study was carried out on TiOxCy powders, both at room temperature and at 150 °C. The present study has revealed that TiOxCy is a sufficiently conductive material whose surface is passivated by a TiO2 film under working conditions, which prevents the full oxidation of the TiOxCy and can thus be considered a stable electrode material for EOR working conditions. This result has also been confirmed through density functional theory (DFT) calculations on a simplified model system. Furthermore, it has been experimentally observed that ethanol molecules adsorb on the TiOxCy surface, inhibiting its oxidation. This result has been confirmed by using in situ Fourier transform infrared spectroscopy (FTIRS). The adsorption of ethanol is expected to favor the EOR in the presence of suitable catalyst nanoparticles supported on TiOxCy.
authors.affiliation: Department of Chemical Sciences, University of Padova , Via Marzolo 1, Padua 35131, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Calvillo
authors.affiliation: Instituto Universitario de Materiales y Nanotecnología, Universidad de La Laguna , Astrofísico F. Sánchez s/n, La Laguna, Tenerife 38071, Spain.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: García
authors.affiliation: Department of Industrial Engineering, University of Padova , Via Marzolo 9, Padua 35131, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Paduano
authors.affiliation: Instituto Universitario de Materiales y Nanotecnología, Universidad de La Laguna , Astrofísico F. Sánchez s/n, La Laguna, Tenerife 38071, Spain.
authors.forename: Olmedo
authors.initials: O
authors.lastname: Guillen-Villafuerte
authors.affiliation: Leopold-Franzens-University Innsbruck, Institute of Physical Chemistry , Innrain 52c, Innsbruck 6020, Austria.
authors.forename: Carlos
authors.initials: C
authors.lastname: Valero-Vidal
authors.affiliation: CNR-IENI , Via Marzolo 1, Padua 35131, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Vittadini
authors.affiliation: CNR-ICCOM , Via Madonna del Piano 10, Sesto Fiorentino, Florence 50019, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Bellini
authors.affiliation: CNR-ICCOM , Via Madonna del Piano 10, Sesto Fiorentino, Florence 50019, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Lavacchi
authors.affiliation: Department of Chemical Sciences, University of Padova , Via Marzolo 1, Padua 35131, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Agnoli
authors.affiliation: Department of Industrial Engineering, University of Padova , Via Marzolo 9, Padua 35131, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Martucci
authors.affiliation: Leopold-Franzens-University Innsbruck, Institute of Physical Chemistry , Innrain 52c, Innsbruck 6020, Austria.
authors.forename: Julia
authors.initials: J
authors.lastname: Kunze-Liebhäuser
authors.affiliation: Instituto Universitario de Materiales y Nanotecnología, Universidad de La Laguna , Astrofísico F. Sánchez s/n, La Laguna, Tenerife 38071, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Pastor
authors.affiliation: Department of Chemical Sciences, University of Padova , Via Marzolo 1, Padua 35131, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Granozzi
keywords: DEFCs; electrochemical stability; intermediate-T; support; titanium oxycarbide