Efficiency as well as stability are highly desired properties for fuel cells. Direct formic acid fuel cells (DFAFCs) offer several advantages to polymer electrolyte membrane and direct methanol fuel cells. Platinum is the most commonly used catalyst material in fuel cells. Electrodes composed of pure platinum lack the adequate electrocatalytic activity needed for oxidation reduction reactions in DFAFCs. Furthermore, a pure platinum anode is highly susceptible to CO poisoning rendering the catalyst inactive. Alloy bimetallic platinum-based nanoparticles have been shown to have high electro-oxidation activity, the ability to oxidize surface adsorbed CO species and are more intolerant to CO poisoning. Iridium platinum bimetallic alloy nanoparticles (IrxPt-100-x) have exhibited excellent catalytic activities for anodic and cathodic reactions. Synthetic methodologies that can specify the size, shape, and composition of IrxPt-100-x nanoparticle alloys are therefore key to advancing DFAFCs.The synthesis of DFAFCs catalysts from block copolymer templates has not yet been fully explored and offers several methods for tuning the size, shape and composition of bimetallic alloy nanoparticles. In this presentation, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymers are investigated for the synthesis of  IrxPt-100-x nanoparticles. The nanoparticles were analyzed via scanning force microscopy (SFM) to determine size, morphology, and structure. Elemental composition was determined through x-ray photoelectron spectroscopy (XPS) and laser ablation inductively-coupled plasma-mass spectrometry (LAICP-MS). Electrochemical measurements were examined in a cyclic voltammetry (CV) mode for the formic acid oxidation reaction. The relationship between the diblock copolymer template, the composition and the activity of IrxPt-100-x electrocatalysts are discussed.

Block copolymer templated synthesis of iridium-platinum alloy nanoparticles for catalysis in fuel cells

247th National Meeting (2014)

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