Yin Zhao-Hua, Huang Yuan, Song Kepeng, Li Tian-Tian, Cui Jun-Yuan, Meng Chao, Zhang Huigang, Wang Jian-Jun
State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
Department of Chemistry, Tsinghua University, Beijing 100084, China.
J Am Chem Soc. 2024 Mar 13;146(10):6846-6855. doi: 10.1021/jacs.3c13746. Epub 2024 Feb 29.
This investigation probes the intricate interplay of catalyst dynamics and reaction pathways during the oxygen evolution reaction (OER), highlighting the significance of atomic-level and local ligand structure insights in crafting highly active electrocatalysts. Leveraging a tailored ion exchange reaction followed by electrochemical dynamic reconstruction, we engineered a novel catalytic structure featuring single Ir atoms anchored to NiOOH (Ir@NiOOH). This novel approach involved the strategic replacement of Fe with Ir, facilitating the transition of selenide precatalysts into active (oxy)hydroxides. This elemental substitution promoted an upward shift in the O 2p band and intensified the metal-oxygen covalency, thereby altering the OER mechanism toward enhanced activity. The shift from a single-metal site mechanism (SMSM) in NiOOH to a dual-metal-site mechanism (DMSM) in Ir@NiOOH was substantiated by in situ differential electrochemical mass spectrometry (DEMS) and supported by theoretical insights. Remarkably, the Ir@NiOOH electrode exhibited exceptional electrocatalytic performance, achieving overpotentials as low as 142 and 308 mV at current densities of 10 and 1000 mA cm, respectively, setting a new benchmark for the electrocatalysis of OER.
本研究探讨了析氧反应（OER）过程中催化剂动力学与反应路径的复杂相互作用，突出了原子水平和局部配体结构见解在制备高活性电催化剂方面的重要性。通过定制的离子交换反应并随后进行电化学动态重构，我们设计了一种新型催化结构，其特征为单Ir原子锚定在NiOOH上（Ir@NiOOH）。这种新方法涉及用Ir战略性地取代Fe，促进硒化物预催化剂向活性（氧）氢氧化物的转变。这种元素取代促进了O 2p能带向上移动并增强了金属 - 氧共价性，从而改变了OER机制以提高活性。原位差分电化学质谱（DEMS）证实了从NiOOH中的单金属位点机制（SMSM）到Ir@NiOOH中的双金属位点机制（DMSM）的转变，并得到了理论见解的支持。值得注意的是，Ir@NiOOH电极表现出卓越的电催化性能，在电流密度分别为10和1000 mA cm时，过电位低至142和308 mV，为OER的电催化设定了新的基准。
