Li Lun, Qiao Lulu, Liu Di, Yu Zhichao, An Keyu, Yang Jiao, Liu Chunfa, Cao Youpeng, Pan Hui
Institute of Applied Physics and Materials Engineering, University of Macau, Macao, SAR, 999078, China.
Department of Physics and Chemistry, Faculty of Science and Technology, University of Macau, Macao, SAR, 999078, China.
Small. 2025 Feb;21(6):e2403992. doi: 10.1002/smll.202403992. Epub 2024 Oct 13.
The transition metal with high valence state in oxyhydroxides can accelerate the reaction kinetics, enabling highly intrinsic OER activity. However, the formation of high-valence transition-metal ions is thermodynamically unfavorable in most cases. Here, a novel strategy is proposed to realize the purpose and reveal the mechanism by constructing amorphous phase and incorporating of elements with the characteristic of Lewis acid or variable charge state. A model catalyst, CeO-NiFeOH, is presented to achieve the modulation of valence state of active site (Ni→Ni→Ni) for improved OER, leading to dominant active sites with high valence state. The CeO-NiFeOH electrode exhibits superior OER performance with overpotential of 214 and 659 mV at 10 and 500 mA cm, respectively (without IR correction), and high stability, which are much better than those of NiOH, NiFeOH and CeO-NiOH. These findings provide an effective strategy to achieve the active metals with high-valence state for highly efficient OER.
羟基氧化物中具有高价态的过渡金属可加速反应动力学，从而具有高度本征的析氧反应（OER）活性。然而，在大多数情况下，高价过渡金属离子的形成在热力学上是不利的。在此，提出了一种新策略，通过构建非晶相并引入具有路易斯酸特性或可变电荷态的元素来实现这一目的并揭示其机制。提出了一种模型催化剂CeO-NiFeOH，以实现对活性位点（Ni→Ni→Ni）价态的调制，从而改善析氧反应，产生具有高价态的主要活性位点。CeO-NiFeOH电极在10和500 mA cm时分别具有214和659 mV的过电位（无IR校正），表现出优异的析氧反应性能和高稳定性，远优于NiOH、NiFeOH和CeO-NiOH。这些发现为实现具有高价态的活性金属以进行高效析氧反应提供了一种有效策略。
