The invention of the proton exchange membrane fuel cell (PEMFC) occurred over a half-century ago and, in spite of extensive developments of its science and its components, its widespread commercialization remains a challenge. Currently, improvements in the durability, performance and manufacturing cost of PEMFCs are required – all of which can be addressed with advances in catalyst function. Platinum (Pt) for example has long been the default anodic and cathodic fuel cell catalyst, which makes resulting fuel cell devices less efficient due to Pt poisoning and slow kinetics for the oxygen reduction reaction (ORR). Recent work in our laboratories has shown that a block copolymer template-directed synthesis of mono- and bimetallic nanoparticle catalysts is an attractive method for preparing and studying high performance fuel cell catalysts. The content of this presentation will describe our investigation of the underlying principles for prescribing the size, spacing and composition of nanocatalysts that can be isolated from self-assembled block copolymers loaded with metallic anions.<br/>The approach offers several advantageous synthetic features compared to solvothermal catalyst synthesis. The approach is highly flexible and allows for the preparation and screening of a variety of mono- and bimetallic catalysts particles (Pt/Au, Pt/Ir, Pt/Cu, etc.). The method allows for the fine-tuning of the catalyst activity by selection of the block copolymer template precursor. The equivalent exercise of isolating and refining catalysts by solvothermal or other techniques often requires a vigilant redesign of the experimental conditions (ligands, solvents, temperature, pressure, new metal salt precursors, etc.) that control the growth and reduction kinetics of the reagents that create the nanocatalysts. Accordingly, the electrocatalytic activity of block copolymer template-directed bimetallic catalysts is presented. Details for the methanol and formic acid oxidation reactions and tolerance to catalyst poisoning are discussed. Preliminary details on a structure–activity relationship between nanocatalysts and their self-assembled block copolymer templates are also presented.

Block copolymer templated mono- and bimetallic catalysts for fuel cell electrocatalysis

253rd National Meeting (2017)

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