The membrane electrode assembly achieves a power density of 0.40 W cm(-2)in a practical H-2/air cell (1.0 bar) and demonstrates significantly enhanced durability under accelerated stability tests. The unique nanoscale X-ray computed tomography verifies the well-distributed ionomer coverage throughout the fibrous carbon network in the catalyst. The highly graphitized more » carbon matrix in the catalyst is beneficial for enhancing the carbon corrosion resistance, thereby promoting catalyst stability. The enhanced intrinsic activity is attributed to the extra graphitic N dopants surrounding the CoN(4)moieties. The distinct porous fibrous morphology and hierarchical structures play a vital role in boosting electrode performance by exposing more accessible active sites, providing facile electron conductivity, and facilitating the mass transport of reactant. Here, a high-power and durable Co-N-C nanofiber catalyst synthesized through electrospinning cobalt-doped zeolitic imidazolate frameworks into selected polyacrylonitrile and poly(vinylpyrrolidone) polymers is reported. Increasing catalytic activity and durability of atomically dispersed metal-nitrogen-carbon (M-N-C) catalysts for the oxygen reduction reaction (ORR) cathode in proton-exchange-membrane fuel cells remains a grand challenge. Improved fuel cell durability was also observed. In a single-cell test, the membrane electrode containing such a catalyst delivered unprecedented volumetric activities of 3.3 A∙cm -3 at 0.9 V or 450 A∙cm -3 extrapolated at 0.8 V, representing the highest reported value in the literature. The catalyst offers a carbon nanonetwork architecture made of microporous nanofibers decorated by uniformly distributed high-density active sites. We report here more » a method of preparing highly efficient, nanofibrous NPMC for cathodic oxygen reduction reaction by electrospinning a polymer solution containing ferrous organometallics and zeolitic imidazolate framework followed by thermal activation. Unconventional catalyst design aiming at maximizing the active site density at much improved mass and charge transports is essential for the next-generation NPMC.
However, a significantly lower turnover frequency at the individual catalytic site renders the traditional carbon-supported NPMCs inadequate in reaching the desired performance afforded by Pt. Nonprecious metal catalysts (NPMCs) represent attractive low-cost alternatives. The high price of Pt creates a major cost barrier for large-scale implementation of polymer electrolyte membrane fuel cells. Significantly improved fuel cell durability was also = ,įuel cell vehicles, the only all-electric technology with a demonstrated >300 miles per fill travel range, use Pt as the electrode catalyst. In a single-cell test, the membrane electrode containing such catalyst delivered an unprecedented volumetric activities of 3.3 A cm-3 at 0.9V or 450 A cm-3 extrapolated at 0.8 V, representing the highest reported value in the literature. The new catalyst offers a carbon nano-network architecture made of microporous nanofibers decorated by uniformly distributed high density active sites. We report here a new method of preparing highly efficient, nanofibrous NPMC for cathodic oxygen reduction reaction by electrospinning a polymer solution containing ferrous organometallics and zeolitic imidazolate framework followed by thermal activation. However, a significantly lower turn-over frequency at the individual catalytic site renders the traditional carbon-supported NPMCs inadequate in reaching the desired performance afforded by Pt. Non-precious metal catalysts (NPMCs) represent attractive low-cost alternatives. The high price of Pt creates a major cost barrier for large-scale implementation of proton exchange membrane fuel cells. Fuel cell vehicles, the only all-electric technology with demonstrated >300 miles/fill travel range, use platinum as the electrode catalyst.
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