Activating lattice oxygen redox reactions in metal oxides to catalyse oxygen evolution
Activating lattice oxygen redox reactions in metal oxides to catalyse oxygen evolution
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DOI：
10.1038/nchem.2695
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发表时间：
2017-05-01
期刊：
影响因子：
21.8
通讯作者：
Shao-Horn, Yang
中科院分区：
文献类型：
--
作者：
Grimaud, Alexis;Diaz-Morales, Oscar;Shao-Horn, Yang
了解催化析氧反应（OER）的材料是如何发挥作用的，对于开发高效的储能技术至关重要。传统上对金属氧化物的OER机理的理解涉及在其表面的金属离子中心和来自水的产物氧分子上的四个协同的质子-电子转移步骤。在这里，使用原位O-18同位素标记质谱，我们提供了直接的实验证据，OER过程中产生的O-2对一些高活性氧化物可以来自晶格氧。能够晶格氧氧化的氧化物也表现出pH依赖的OER活性的可逆氢电极规模，表明非协调的质子-电子转移的OER机制。基于我们的实验数据和密度泛函理论计算，我们讨论的机制是从根本上不同于传统的计划，并表明，增加金属-氧键的共价性是至关重要的触发晶格氧氧化，使非协调质子-电子转移过程中OER。
Understanding how materials that catalyse the oxygen evolution reaction (OER) function is essential for the development of efficient energy-storage technologies. The traditional understanding of the OER mechanism on metal oxides involves four concerted proton-electron transfer steps on metal-ion centres at their surface and product oxygen molecules derived from water. Here, using in situ O-18 isotope labelling mass spectrometry, we provide direct experimental evidence that the O-2 generated during the OER on some highly active oxides can come from lattice oxygen. The oxides capable of lattice-oxygen oxidation also exhibit pH-dependent OER activity on the reversible hydrogen electrode scale, indicating non-concerted proton-electron transfers in the OER mechanism. Based on our experimental data and density functional theory calculations, we discuss mechanisms that are fundamentally different from the conventional scheme and show that increasing the covalency of metal-oxygen bonds is critical to trigger lattice-oxygen oxidation and enable non-concerted proton-electron transfers during OER.