Design and fabrication of inexpensive and efficient oxygen evolution reaction (OER) catalysts are of great importance for polymer electrolyte membrane water electrolyzers (PEMWEs). Although the best electrocatalyst is IrO₂ for OER in the PEMWEs, the practical application of Ir has been impeded because of its high cost and limited activity. Herein, a galvanic replacement reaction mechanism was developed for the preparation of polycrystalline Ni–Ir nanocages (NCs) by using Ni nanoparticles as templates. The formation of Ni–Ir NCs achieves the enhancement of OER catalytic performance, accompanied by the reduction of Ir loading but significantly increasing the efficiency of Ir atoms. The as-prepared Ni_2.53Ir NCs exhibit improved catalytic activity toward OER in acid solution, which requires only an overpotential of 302 mV to deliver a current density of 10 mA/cm². At an overpotential of 300 mV, the Ir-based mass activity of Ni_2.53Ir catalysts reaches 114.7 mA/mg_Ir, which is 2.1 times higher than that of commercial Ir black. The obtained Ni_2.53Ir NCs could be potentially applied for industrial scale PEMWE systems.

中文翻译：

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Ni-Ir纳米笼的合成及其对氧析出反应的改善的电催化性能

对于聚合物电解质膜水电解槽（PEMWE），廉价和有效的析氧反应（OER）催化剂的设计和制造非常重要。尽管PEMWEs中最好的电催化剂是用于OER的IrO ₂，但由于Ir的高成本和有限的活性，它的实际应用受到了阻碍。在本文中，开发了一种电置换反应机理，以Ni纳米粒子为模板制备多晶Ni–Ir纳米笼（NC）。Ni-Ir NCs的形成增强了OER催化性能，并伴随着Ir含量的降低，但显着提高了Ir原子的效率。制备的Ni _2.53Ir NCs在酸性溶液中显示出对OER的改善的催化活性，仅需302 mV的超电势即可提供10 mA / cm ²的电流密度。在300 mV的超电势下，Ni _2.53 Ir催化剂的基于Ir的质量活度达到114.7 mA / mg _Ir，这是市售Ir黑的2.1倍。获得的Ni _2.53 Ir NCs可以潜在地应用于工业规模的PEMWE系统。