ORIGINAL PAPER Preparation and evaluation of carbon-supported catalysts for ethanol oxidation A. Bonesi & M. Asteazaran & M. S. Moreno & G. Zampieri & S. Bengio & W. Triaca & A. M. Castro Luna Received: 14 August 2012 /Revised: 23 May 2013 /Accepted: 26 May 2013 /Published online: 11 June 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract Supported PtSnIr/C, PtSn/C, and IrSn/C catalysts with potential application in a direct alcohol fuel cell were prepared by chemical reduction employing Pechini methodolo- gy. The catalyst particles were characterized by high-resolution transmission electron microscopy, energy-dispersive X-ray spec- troscopy, and X-ray photoelectron spectroscopy (XPS). Linear sweep voltammetry (LV), chronoamperometry, and electro- chemical impedance spectroscopy (EIS) measurements were performed by using a glassy carbon working electrode covered with the catalyst in a 1 M ethanol+0.5 M H 2 SO 4 solution at 60 °C. It was demonstrated through XPS that PtSnIr/C and IrSn/C contain both IrO 2 and SnO 2 . LVand chronoamperometry show a better catalytic behavior for ethanol oxidation on PtSnIr/C in the low-potential region and the improvement is attributed to the presence of both Sn and Ir oxides. The EIS accurately established that PtSnIr/C improved ethanol oxidation at lower potentials than PtSn/C. Keywords Platinum . Iridium . Tin . Ethanol . DEFC . Nanoparticles . Electrochemical impedance spectroscopy Introduction Fuel cells that employ liquid alcohols such as a direct ethanol fuel cell (DEFC) are attractive to power portable devices because their theoretical cell voltage is similar to that obtained when hydrogen is oxidized [1–3] and in the case of ethanol, its complete electro-oxidation involves a 12- electron process. Unlike hydrogen, ethanol is easy to handle, transport, and store and no previous reformer system is necessary. Nevertheless, DEFC undergoes slow kinetics of alcohol oxidation on electrode surfaces. Efficiency is cur- rently quite low for that cell [4]. To achieve the maximum chemical energy from an alcohol molecule, it should be completely oxidized to CO 2 . Research into alcohol fuel cell catalysis is focused primarily on increasing the catalytic efficiency of the electrode materials [5]. Platinum is consid- ered as the most active catalyst for ethanol oxidation at low temperature. However, the main problem in achieving an efficient conversion is that ethanol oxidation can be conducted through different paths. Thus, large amounts of partially oxidized products such as acetaldehyde and acetic acid have been detected at low temperature as the main products in ethanol oxidation (EO) [5, 6]. Moreover, strong- ly adsorbed species such as CO and CH x , which are difficult to convert to CO 2 , block the surface and hinder further alcohol adsorption causing low-power densities at DEFC. A good ethanol catalyst should have a great capacity to electro-oxidize ethanol to CO 2 and water, but Pt alone shows a low capability to sufficiently favor the C–C rupture of the ethanol molecule. Therefore, the electrocatalytic concern is to cope with a material that facilitates ethanol complete oxidation and shifts the onset oxidation potential to lower values. It appears that an improvement in EO electrocatalysis is possible with multifunctional Pt-based combinations. The superior performance of binary or ternary Pt-based catalysts relative to a pure Pt catalyst has been explained in terms of A. Bonesi : M. Asteazaran : W. Triaca : A. M. Castro Luna (*) Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, UNLP-CONICET, La Plata, Buenos Aires, Argentina e-mail: castrolu@gmail.com A. M. Castro Luna e-mail: castrolu@inifta.unlp.edu.ar M. Asteazaran : A. M. Castro Luna Centro de Investigación y Desarrollo en Ciencia y Tecnología de Materiales (CITEMA), Facultad Regional La Plata, UTN, La Plata, Argentina M. S. Moreno : G. Zampieri : S. Bengio Centro Atómico Bariloche, Comisión Nacional de Energía Atómica (CAB-CNEA), Bariloche, Argentina J Solid State Electrochem (2013) 17:1823–1829 DOI 10.1007/s10008-013-2138-8