1c:I[419806,["/_next/static/chunks/bb923814e1f4d2e9.js","/_next/static/chunks/dd3ee9f5b7716ca6.js","/_next/static/chunks/4204a0ae82542ca8.js","/_next/static/chunks/30036bedc5269936.js","/_next/static/chunks/6e1aa89a642f40be.js","/_next/static/chunks/cd5e572bc3e4eb92.js","/_next/static/chunks/8ffd0b71567920d8.js","/_next/static/chunks/67ea6dfd21f16c5f.js","/_next/static/chunks/24eb4379f68013fd.js","/_next/static/chunks/b8cd775ffdf935bd.js","/_next/static/chunks/983103cd9eb7b428.js","/_next/static/chunks/d4ac9dcf27f6ff52.js","/_next/static/chunks/294b9525248c8e5f.js"],"default"] 1d:T432,Control of structure at the atomic level can precisely and effectively tune catalytic properties of materials, enabling enhancement in both activity and durability. We synthesized a highly active and durable class of electrocatalysts by exploiting the structural evolution of platinum-nickel (Pt-Ni) bimetallic nanocrystals. The starting material, crystalline PtNi3 polyhedra, transforms in solution by interior erosion into Pt3Ni nanoframes with surfaces that offer three-dimensional molecular accessibility. The edges of the Pt-rich PtNi3 polyhedra are maintained in the final Pt3Ni nanoframes. Both the interior and exterior catalytic surfaces of this open-framework structure are composed of the nanosegregated Pt-skin structure, which exhibits enhanced oxygen reduction reaction (ORR) activity. The Pt3Ni nanoframe catalysts achieved a factor of 36 enhancement in mass activity and a factor of 22 enhancement in specific activity, respectively, for this reaction (relative to state-of-the-art platinum-carbon catalysts) during prolonged exposure to reaction conditions.1e:T407,Achieving high catalytic performance with the lowest possible amount of platinum is critical for fuel cell cost reduction. Here we describe a method of preparing highly active yet stable electrocatalysts containing ultralow-loading platinum content by using cobalt or bimetallic cobalt and zinc zeolitic imidazolate frameworks as precursors. Synergistic catalysis between strained platinum-cobalt core-shell nanoparticles over a platinum-group metal (PGM)-free catalytic substrate led to excellent fuel cell performance under 1 atmosphere of O₂ or air at both high-voltage and high-current domains. Two catalysts achieved oxygen reduction reaction (ORR) mass activities of 1.08 amperes per milligram of platinum (A mg_Pt ^-1) and 1.77 A mg_Pt ^-1 and retained 64% and 15% of initial values after 30,000 voltage cycles in a fuel cell. Computational modeling reveals that the interaction between platinum-cobalt nanoparticles and PGM-free sites improves ORR activity and durability.1f:T4fa,We present that heavy use of scarce Pt in the electrodes poses a barrier to the application of proton exchange membrane fuel cells (PEMFCs) for transportation. Although some automakers can now commercialize fuel cell electric vehicles (FCEVs) with as little as 30 g of Pt, this is still substantially more than what incumbent internal combustion engine vehicles use (2-8 g of precious metals). A long-term target of <5 g of Pt-group metals per vehicle is probably needed to be sustainable. Since W. R. Grove’s invention of the fuel cell in 1839, most breakthroughs in fuel cell performance have been associated with an increase in the so-called three-phase interface—the interface where the reactant gas meets electrons in the solid phase and protons in the electrolyte phase. Pt is made into nanoparticles and supported on carbon black to increase the mass-specific Pt surface area and to secure large pores for reactant oxygen gas to access Pt. Solid electrolyte such as the perfluorosulfonic acid (PFSA) ionomer is blended with the catalyst to carry protons to the Pt surface. Lastly, despite a long history of maximizing the three-phase interfacial area, one must realize that an optimized three-phase interface does not equal a maximum Pt/ionomer interface area.

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