Shifting Oxygen Charge Towards Octahedral Metal: A Way to Promote Water Oxidation on Cobalt Spinel Oxides
Shifting Oxygen Charge Towards Octahedral Metal: A Way to Promote Water Oxidation on Cobalt Spinel Oxides
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DOI：
10.1002/anie.201902114
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发表时间：
2019-04-23
影响因子：
16.6
通讯作者：
Xu, Zhichuan J.
中科院分区：
文献类型：
--
作者：
Sun, Shengnan;Sun, Yuanmiao;Xu, Zhichuan J.
钴尖晶石氧化物是一类很有前途的催化析氧反应的过渡金属氧化物。它们的催化活性取决于电子结构。在尖晶石氧化物晶格中，每个氧阴离子在其四个最近的过渡金属阳离子之间共享，其中一个位于四面体间隙内，其余三个阳离子位于八面体间隙中。本工作揭示了氧负离子电荷分布对氧化还原活性结构单元Co-O电子结构的影响。氧负离子的电荷倾向于向八面体占据的Co而不是四面体占据的Co移动，从而在八面体Co和O之间产生强的轨道相互作用。因此，OER活性可以通过将更多的Co推入八面体位点或将氧电荷向CoO 6八面体中的氧化还原活性金属中心移动来促进。
Cobalt spinel oxides are a class of promising transition metal (TM) oxides for catalyzing oxygen evolution reaction (OER). Their catalytic activity depends on the electronic structure. In a spinel oxide lattice, each oxygen anion is shared amongst its four nearest transition metal cations, of which one is located within the tetrahedral interstices and the remaining three cations are in the octahedral interstices. This work uncovered the influence of oxygen anion charge distribution on the electronic structure of the redox-active building block Co-O. The charge of oxygen anion tends to shift toward the octahedral-occupied Co instead of tetrahedral-occupied Co, which hence produces strong orbital interaction between octahedral Co and O. Thus, the OER activity can be promoted by pushing more Co into the octahedral site or shifting the oxygen charge towards the redox-active metal center in CoO6 octahedra.