Yu Peng-Cheng, Zhang Xiao-Long, Zhang Tian-Yun, Tao Xu-Ying-Nan, Yang Yu, Wang Ye-Hua, Zhang Si-Chao, Gao Fei-Yue, Niu Zhuang-Zhuang, Fan Ming-Hui, Gao Min-Rui
Division of Nanomaterials & Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China.
J Am Chem Soc. 2024 Jul 24;146(29):20379-20390. doi: 10.1021/jacs.4c05983. Epub 2024 Jul 16.
Scarce and expensive iridium oxide is still the cornerstone catalyst of polymer-electrolyte membrane electrolyzers for green hydrogen production because of its exceptional stability under industrially relevant oxygen evolution reaction (OER) conditions. Earth-abundant transition metal oxides used for this task, however, show poor long-term stability. We demonstrate here the use of nitrogen-doped cobalt oxide as an effective iridium substitute. The catalyst exhibits a low overpotential of 240 mV at 10 mA cm and negligible activity decay after 1000 h of operation in an alkaline electrolyte. Incorporation of nitrogen dopants not only triggers the OER mechanism switched from the traditional adsorbate evolution route to the lattice oxygen oxidation route but also achieves oxygen nonbonding (O) states as electron donors, thereby preventing structural destabilization. In a practical anion-exchange membrane water electrolyzer, this catalyst at anode delivers a current density of 1000 mA cm at 1.78 V and an electrical efficiency of 47.8 kW-hours per kilogram hydrogen.
稀缺且昂贵的氧化铱仍然是用于绿色制氢的聚合物电解质膜电解槽的关键催化剂，因为它在工业相关析氧反应（OER）条件下具有出色的稳定性。然而，用于此任务的储量丰富的过渡金属氧化物显示出较差的长期稳定性。我们在此展示了使用氮掺杂氧化钴作为有效的铱替代物。该催化剂在10 mA cm时具有240 mV的低过电位，并且在碱性电解质中运行1000小时后活性衰减可忽略不计。氮掺杂剂的引入不仅触发了OER机制从传统的吸附质析出途径转变为晶格氧氧化途径，还实现了作为电子供体的氧非键合（O）状态，从而防止结构不稳定。在实际的阴离子交换膜水电解槽中，该催化剂在阳极处1.78 V时可提供1000 mA cm的电流密度以及每千克氢气47.8千瓦时的电效率。
