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Porous Sb–SnO2 nanowires were synthesized as a support for IrO2 by an electrospinning method. The thus prepared catalyst exhibits enhanced mass activity toward OER.

The CARISMA conference series is specifically devoted to the challenges in developing fuel cell materials and membrane electrode assemblies for the medium and high temperature range targeted for transport and stationary applications. The conference will be the opportunity for presentation of recent results, discussion and debate on the solutions sought internationally to the bottlenecks associated with operation at higher temperatures, with an international programme of invited lectures, oral and poster contributions, organized to promote a review of important issues related to materials development and durability for PEMFC systems. . Similar PtNi catalysts are being developed in continuous nanostructured thin-film (NSTF) format, demonstrating achievement of the mass activity target, while yielding voltage higher than 0.6 V at 1.5 A/cm 2 . Core-shell catalysts have also been developed based on deposition of Pt monolayer shells on pre-formed Pt-free or low-Pt cores. This catalyst technology, along with innovative synthesis techniques, was recently licensed by a major catalyst manufacturer. Modified catalysts capable of withstanding the destructive conditions of start-up, shutdown, and cell reversal have been demonstrated using low levels of IrRu oxygen evolution catalyst. NSTF catalysts modified with IrRu have exceeded 5000 simulated start-up/shutdown cycles, and more than 200 cell reversals (0.2 A/cm 2 ), while meeting performance durability targets, all at a PGM loading of only 0.135 mg/cm 2 . Development of high-conductivity perfluorinated ionomers with low swelling, using multi-acid side chain polymers with perfluoro imide and sulfonic acid proton donors, has resulted in membranes capable of meeting nearly all DOE targets; even under the hottest and driest conditions targeted (120 °C, 40 kPa H 2 O vapor) these membranes have area specific resistance within 15% of the 2017 target value, and are capable of meeting all other DOE membrane performance and durability targets under cooler and wetter conditions. The Florida Solar Energy Center (FSEC) has led the U.S. Department of Energy (DOE) High Temperature Membrane Working Group (HTMWG since 2006. The HTMWG investigates membrane performance at elevated temperature/low relative humidity conditions. For the final three years of the project, FSEC has worked with six teams to develop membrane electrode assembly (MEA) fabrication methods for their respective membranes. This presentation details the challenges associated with MEA fabrication of various membrane types, along with the performance results from several HTMWG membranes. The MEA fabrication technique utilized by FSEC is to suspend the membrane vertically in front of a heated plate, and then spray catalyst-ink slurry onto the membrane. Following electrode application, the CCM is hot pressed to ensure good interfacial contact. Through these procedures, several challenges were identified. First, during electrode application, the membrane can swell due to the high solvent content in the ink and the heat from t...

Proton exchange membrane steam electrolyzers suffer from insufficient catalyst activity and durability due to the slow reaction kinetics for oxygen evolution reaction (OER) and poor durability under harsh operating environments. Aiming at enhancement of oxygen electrode kinetics and durability, composite support materials for iridium oxide are synthesized via in situ phosphorization reaction on tin doped indium oxide and possess functionalities of high electronic and intrinsic proton conductivity. At 130 C under a water vapor atmosphere an overall conductivity of 0.72 S cm À1 is achieved with a contribution of around 10 À2 S cm À1 proton conductivity. The support structure of three-dimensionally ordered hexagonal arrays displays a high specific surface area of 180 m 2 g À1 . Benefiting from the mixed conductivities and porous structure in the composite support materials, the supported IrO 2 catalysts exhibit about five times enhancement of the OER activity in acidic electrolytes. The improved catalytic performance for the OER was further confirmed by PEM electrolyzer tests at 130 C. A test of such a steam electrolyzer cell at 350 mA cm À2 shows good durability within a period of up to 1150 hours. Broader contextHydrogen as an energy carrier constitutes an important part of an environmentally benign solution to the world energy crisis. Water electrolysis is one of the most practical ways to produce pure hydrogen from renewable energy sources. A challenge for proton exchange membrane based electrolyzers is the insufficient catalyst activity and durability for the oxygen evolution reaction. The present work addresses the issues by designing and synthesizing composite support materials with both electronic and protonic conductivity. The materials were evaluated in proton exchange membrane steam electrolyzers at 130 C showing enhanced performance in terms of activity and durability.