{"title":"Triggering the Dual-Metal-Site Lattice Oxygen Mechanism with In Situ-Generated Mn3+ Sites for Enhanced Acidic Oxygen Evolution","authors":"Jianyun Liu, Tanyuan Wang, Mingzi Sun, Mengyi Liao, Shiyu Wang, Shuxia Liu, Hao Shi, Yang Liu, Yue Shen, Ruiguo Cao, Yunhui Huang, Bolong Huang, Qing Li","doi":"10.1021/jacs.4c14338","DOIUrl":null,"url":null,"abstract":"The development of high-performance non-Ir/Ru catalysts for the oxygen evolution reaction (OER) in acid is critical for the applications of proton exchange membrane water electrolyzers (PEMWEs). Here, we report a new kind of heterostructure catalyst by loading 5.8% Ag nanoparticles on MnO nanorods (Ag/MnO) for acidic OER. The as-prepared Ag/MnO requires only an overpotential of 196 mV for the OER at a current density of 10 mA cm<sup>–2</sup> in 0.5 M H<sub>2</sub>SO<sub>4</sub> and operates in a PEMWE for over 300 h at a current density of 200 mA cm<sup>–2</sup>, representing one of the best non-Ir/Ru OER catalysts. <i>Operando</i> X-ray absorption spectroscopy confirms that the introduction of trace Ag can promote the generation of highly active Mn<sup>3+</sup>–O sites with oxygen vacancies at a low voltage, leading to a dual-metal-site lattice oxygen-mediated pathway with faster kinetics than the adsorbate evolution mechanism. Theoretical calculations indicate that the trace Ag promotes the overlap between the d orbitals of Mn and the s, p orbitals of O, thereby activating the lattice oxygen and reducing the OER energy barrier. The dissolution of Mn is also suppressed by Ag due to the increased energy for vacancy formation of Mn, where the stability number reaches a high value of 3058, supporting improved structural stability.","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":"61 1","pages":""},"PeriodicalIF":14.4000,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the American Chemical Society","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/jacs.4c14338","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The development of high-performance non-Ir/Ru catalysts for the oxygen evolution reaction (OER) in acid is critical for the applications of proton exchange membrane water electrolyzers (PEMWEs). Here, we report a new kind of heterostructure catalyst by loading 5.8% Ag nanoparticles on MnO nanorods (Ag/MnO) for acidic OER. The as-prepared Ag/MnO requires only an overpotential of 196 mV for the OER at a current density of 10 mA cm–2 in 0.5 M H2SO4 and operates in a PEMWE for over 300 h at a current density of 200 mA cm–2, representing one of the best non-Ir/Ru OER catalysts. Operando X-ray absorption spectroscopy confirms that the introduction of trace Ag can promote the generation of highly active Mn3+–O sites with oxygen vacancies at a low voltage, leading to a dual-metal-site lattice oxygen-mediated pathway with faster kinetics than the adsorbate evolution mechanism. Theoretical calculations indicate that the trace Ag promotes the overlap between the d orbitals of Mn and the s, p orbitals of O, thereby activating the lattice oxygen and reducing the OER energy barrier. The dissolution of Mn is also suppressed by Ag due to the increased energy for vacancy formation of Mn, where the stability number reaches a high value of 3058, supporting improved structural stability.
开发用于酸性氧进化反应(OER)的高性能非离子/铀催化剂对于质子交换膜水电解槽(PEMWE)的应用至关重要。在此,我们报告了一种新型异质结构催化剂,即在氧化锰纳米棒(Ag/MnO)上负载 5.8% 的 Ag 纳米颗粒,用于酸性 OER。制备的 Ag/MnO 在 0.5 M H2SO4 中以 10 mA cm-2 的电流密度进行 OER 时仅需 196 mV 的过电位,并可在 PEMWE 中以 200 mA cm-2 的电流密度运行 300 小时以上,是最好的非铁/铁氧体 OER 催化剂之一。操作性 X 射线吸收光谱证实,痕量 Ag 的引入可在低电压下促进具有氧空位的高活性 Mn3+-O 位点的生成,从而形成双金属位点晶格氧介导的途径,其动力学速度快于吸附剂演化机制。理论计算表明,痕量 Ag 促进了 Mn 的 d 轨道与 O 的 s、p 轨道之间的重叠,从而激活了晶格氧并降低了 OER 的能垒。由于 Mn 空位形成的能量增加,Ag 也抑制了 Mn 的溶解,使稳定数达到 3058 的高值,从而支持了结构稳定性的提高。
期刊介绍:
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