Combine and conquer Platinum (Pt)–group metals, which are scarce and expensive, are used for the demanding oxygen reduction reaction (ORR) in hydrogen fuel cells. One competing approach for reducing their use is to create nanoparticles with earth-abundant metals to increase their activity and surface area; another is to replace them with metals such as cobalt (Co) in carbide or nitride sites. Chong et al. thermally activated a Co metal-organic framework compound to create ORR-active Co sites and then grew PtCo alloy nanoparticles on this substrate. The resulting catalyst had high activity and durability, despite its relatively low Pt content. Science, this issue p. 1276 Active cobalt sites and platinum-cobalt nanoparticles are combined in a highly active and durable oxygen reduction catalyst. 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 mgPt−1) and 1.77 A mgPt−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.

中文翻译：

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源自咪唑酯骨架的超低负载铂钴燃料电池催化剂

结合并征服稀有且昂贵的铂 (Pt) 族金属，用于氢燃料电池中要求苛刻的氧还原反应 (ORR)。减少它们使用的一种竞争方法是用地球上丰富的金属制造纳米粒子，以增加它们的活性和表面积；另一种方法是在碳化物或氮化物位点用钴 (Co) 等金属代替它们。冲等人。热活化 Co 金属有机骨架化合物以产生 ORR 活性 Co 位点，然后在该基板上生长 PtCo 合金纳米颗粒。尽管 Pt 含量相对较低，但所得催化剂具有高活性和耐久性。科学，这个问题 p。1276 个活性钴位点和铂钴纳米粒子结合在一个高活性和耐用的氧还原催化剂中。以尽可能低的铂量实现高催化性能对于降低燃料电池成本至关重要。在这里，我们描述了一种通过使用钴或双金属钴和锌沸石咪唑酯骨架作为前体制备含有超低负载铂含量的高活性但稳定的电催化剂的方法。在无铂族金属 (PGM) 的催化基材上，应变的铂钴核壳纳米粒子之间的协同催化导致燃料电池在 1 个大气压 O2 或空气下的高压和高电流域均具有出色的性能。两种催化剂实现了 1.08 安培/毫克铂 (A mgPt-1) 和 1.77 A mgPt-1 的氧还原反应 (ORR) 质量活性，并在燃料电池中 30,000 次电压循环后保持了初始值的 64% 和 15%。