School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, P. R. China.
Department of Chemistry, Guangdong Provincial Key Laboratory of Energy Materials for Electric Power, and Key Laboratory of Energy Conversion and Storage Technologies (Ministry of Education), Southern University of Science and Technology, Shenzhen, 518055, P. R. China.
Small. 2022 Apr;18(17):e2107594. doi: 10.1002/smll.202107594. Epub 2022 Mar 28.
Water splitting to produce hydrogen is an effective means to alleviate the energy crisis. The anodic oxygen-evolving reaction (OER) limits the overall efficiency due to its high energy barrier. To address this, layered double hydroxides (LDHs) with high catalytic activities have been widely studied, especially those modified with CeO , either bound to the surface or doped into interior. However, experimental evidence for the atomic-level understanding of the mechanism for the enhanced catalytic performance is conspicuously missing. Herein, anchoring CeO nanoparticles onto Co LDH, based on the thoughts of loading capacity and size effect to regulate the properties of the interface and to optimize the performance, is attempted. The electronic interactions are studied by X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS), revealing electron transfer from Co to Ce that leads to an increase in Co . The strong Lewis acidity of Co helps the binding of OH , which is conducive to the formation and transformation of oxygen-containing intermediates. Providing evidence is the formation of one of the key intermediates Co-OOH at a sizably reduced potential as monitored by in situ Raman spectroscopy. With this work, the atomic level correlation of site-specific electronic interactions with the enhanced catalytic performance is clearly established.
水分解产生氢气是缓解能源危机的有效手段。由于阳极析氧反应（OER）的能量势垒较高，其限制了整体效率。为了解决这个问题，具有高催化活性的层状双氢氧化物（LDHs），特别是那些用 CeO 修饰的，无论是结合在表面上还是掺杂到内部的，都得到了广泛的研究。然而，对于增强催化性能的原子级理解机制的实验证据却明显缺失。在此，基于负载能力和尺寸效应的思路，尝试将 CeO 纳米粒子锚定在 Co LDH 上，以调节界面的性质并优化性能。通过 X 射线光电子能谱（XPS）和电子能量损失能谱（EELS）研究电子相互作用，发现 Co 到 Ce 的电子转移导致 Co 的增加。Co 的强路易斯酸度有助于 OH 的结合，这有利于含氧中间体的形成和转化。原位拉曼光谱监测表明，其中一个关键中间体 Co-OOH 的形成所需的电位明显降低，这为上述结论提供了证据。通过这项工作，明确建立了特定位置的电子相互作用与增强的催化性能之间的原子级相关性。
