A composite of mesoporous carbon (MC) with poly(3,4‐ethylenedioxythiophene) (PEDOT) is studied as catalyst support for platinum nanoparticles. The durability of commercial Pt/carbon and Pt/MC‐PEDOT as cathode catalyst is investigated by invoking air‐fuel boundary at the anode side so as to foster carbon corrosion at the cathode side of a polymer electrolyte fuel cell (PEFC). Pt/MC‐PEDOT shows higher resistance to carbon corrosion in relation to Pt/C. Electrochemical techniques such as cyclic voltammetry (CV) and impedance measurements are used to evaluate the extent of degradation in the catalyst layer. It is surmised that the resistance of MC‐PEDOT as catalyst support toward electrochemical oxidation makes Pt/MC‐PEDOT a suitable and stable cathode catalyst for PEFCs.

In situ polymerization of 3,4-ethylenedioxythiophene with sol-gel-derived mesoporous carbon ͑MC͒ leading to a new composite and its subsequent impregnation with Pt nanoparticles for application in polymer electrolyte fuel cells ͑PEFCs͒ is reported. The composite exhibits good dispersion and utilization of platinum nanoparticles akin to other commonly used microporous carbon materials, such as carbon black. Pt-supported MC-poly͑3,4-ethylenedioxythiophene͒ ͑PEDOT͒ composite also exhibits promising electrocatalytic activity toward oxygen reduction reaction, which is central to PEFCs. The PEFC with Pt-loaded MC-PEDOT support exhibits 75% of enhancement in its power density in relation to the PEFC with Pt-loaded pristine MC support while operating under identical conditions. It is conjectured that Pt-supported MC-PEDOT composite ameliorates PEFC performance/ durability on repetitive potential cycling. © 2010 The Electrochemical Society. ͓DOI: 10.1149/1.3486172͔ All rights reserved. Commercial viability of the polymer electrolyte fuel cells ͑PEFCs͒ requires almost an order of magnitude reduction in Pt usage with improved performance and durability.1-5 The U.S. Department of Energy has set targets for electrocatalyst performance for the year 2010 at a mass activity of 0.44 A/mg ͑Pt͒ as compared against the current value of 0.28 A/mg ͑Pt͒ and an electrochemical surface area ͑ESA͒ Ͻ40% after accelerated aging. In the literature, 6-16 efforts are being expended to improve the performance and durability of electrocatalysts in PEFCs by alloying Pt with transition metals, such as Ru, Ir, Co, Ti, Zr, Sn, etc., heat-treatment of Pt-based alloys, preparation of core-shell catalysts, dealloying Pt metal alloys, and adapting conducting polymers for developing a durable porous catalyst support with a suitable surface area.A fuel cell catalyst support should have a large surface area with adequate surface functionalities for finely dispersing catalytic metal particles, high electrical conductivity for providing electrical pathways, and highly developed mesoporosity to facilitate diffusion of reactants and products in conjunction with high electrochemical stability during long-term operation. 17,18 Carbon supports, such as carbon black and activated carbon that are being currently used, usually exhibit a large surface area but their pore structures are primarily microporous 19 with pore sizes Ͻ2 nm, which makes the microporous structures incompatible for transporting the reactants; besides, catalyst particles get buried in the micropores making them inaccessible to fuel 20,21 and hence to the overall electrochemical process. Furthermore, these carbon supports, being prone to corrosion caused by electrochemical oxidation during repetitive PEFC cycling, limit its operational life. [22][23][24]

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Poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (styrene sulphonic acid) (PSSA) supported platinum (Pt) electrodes for application in polymer electrolyte fuel cells (PEFCs) are reported. PEDOT-PSSA support helps Pt particles to be uniformly distributed on to the electrodes, and facilitates mixed electronic and ionic (H + -ion) conduction within the catalyst, ameliorating Pt utilization. The inherent proton conductivity of PEDOT-PSSA composite also helps reducing Nafion content in PEFC electrodes. During prolonged operation of PEFCs, Pt electrodes supported onto PEDOT-PSSA composite exhibit lower corrosion in relation to Pt electrodes supported onto commercially available Vulcan XC-72R carbon. Physical properties of PEDOT-PSSA composite have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. PEFCs with PEDOT-PSSA-supported Pt catalyst electrodes offer a peak power-density of 810 mW cm -2 at a load current-density of 1800 mA cm -2 with Nafion content as low as 5 wt.% in the catalyst layer. Accordingly, the present study provides a novel alternative support for platinized PEFC electrodes.