© 2016 Portuguese Society of Materials (SPM). Published by Elsevier España, S.L.U. All rights reserved. http://dx.doi.org/10.1016/j.ctmat.2017.01.001 Ciência & Tecnologia dos Materiais 28 (2016) 88–98 ScienceDirect Available online at www.sciencedirect.com http://ees.elsevier.com/ctmat Special Issue on New Challenges in Energy Materials Key issues to high electroactivity for methanol oxidation and oxygen reduction of Pt-based supported catalyst in fuel cells relevant environment A.I. de Sá a , A. Capelo a , A. Esteves a , L. Cangueiro b , A. Almeida b , R. Vilar a , C.M. Rangel* a Laboratório Nacional de Energia e Geologia (LNEG), Paço do Lumiar, 22, 1649-038 Lisboa, Portugal b Instituto Superior Técnico (IST), Av. Rovisco Pais, 1049-001 Lisboa, Portugal Abstract In this work some of the key issues which affect the performance of catalysts for the anode and cathode electrodes in Direct Methanol Fuel Cells are analyzed. To deal with present challenges and overcome limitations different approaches have been implemented, which include catalyst support diversification and functionalization, control of particle size and the introduction of Pt alloying and heat treatment in order to enhance the rate of critical reactions such as CO electroxidation and oxygen reduction reaction and also reduce Pt loading. A catalyst design strategy has been devised which incorporates the mentioned approaches in order to tackle various critical aspects for both electroactivity and stability, considered essential to boost Direct Methanol Fuel Cells technology. © 2016 Portuguese Society of Materials (SPM). Published by Elsevier España, S.L.U.. All rights reserved. Keywords: Methanol oxidation; Pt-based catalyst; carbon functionalization; oxygen reduction. 1. Introduction * Direct Methanol Fuel Cells (DMFCs) are electro- chemical devices where methanol oxidation occurs to produce electricity and heat. Basically, the device is similar to a battery since it converts the chemical energy of fuel and oxidant into electric energy; yet unlike batteries, fuel cells do not need recharging: the fuel is continuously supplied to the anode and the oxidant to the cathode. Methanol oxidation occurs with the release of protons and electrons; the protons go through a conductive membrane to the cathode, where oxygen is introduced and reduced to form water; the electrons go through the external circuit and correspond to energy produced that can be converted into work. The main disadvantage is the release of CO2 as the product of the methanol oxidation reaction (MOR). However, in a * Corresponding author. E-mail address: carmen.rangel@lneg.pt (C.M. Rangel) sustainable energy future, the cells should be associated with carbon capture and recycling (CCR) technology, closing the loop of harmful emissions [1,2] with methanol being produced from renewable sources [3]. DMFCs have some advantages when compared to hydrogen fuel cells: methanol can be transported and store in liquid phase, using the infrastructure for liquid fuels already available [4,5]. This flexibility on fuel handling makes this technology not only attractive for large scale energy production and transportation, but well suited for small portable applications, for example in consumer electronic devices [4-8]. The DMFCs are projected to reach a market of USD 188.82 Million by 2020 [9]. The portable application market segment is expected to show the highest growth rate with DMFCs, called to fill in the gap between energy demand and energy storage capacity. The energy density of methanol is higher than that of hydrogen [8] and also of lithium ion batteries [6,7]. Apart from that, easy/short time refueling and cold