Bai Xue, Ren Zhiyu, Du Shichao, Meng Huiyuan, Wu Jun, Xue Yuzhu, Zhao Xiaojun, Fu Honggang
Tianjin Key Laboratory of Structure and Performance for Functional Molecules, Key Laboratory of Inorganic-Organic Hybrid Functional Material Chemistry Ministry of Education of the People's Republic of China, Tianjin Normal University, Tianjin 300387, China.
Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China.
Sci Bull (Beijing). 2017 Nov 30;62(22):1510-1518. doi: 10.1016/j.scib.2017.10.019. Epub 2017 Oct 26.
Gaining insight into the structure evolution of transition-metal phosphides during anodic oxidation is significant to understand their oxygen evolution reaction (OER) mechanism, and then design high-efficiency transition metal-based catalysts. Herein, NiCoP nanowires (NWs) vertically grown on Ni foam were adopted as the target to explore the in-situ morphology and chemical component reconstitution during the anodic oxidation. The major factors causing the transformation from NiCoP into the hierarchical NiCoP@CoNi(OOH) NWs are two competing reactions: the dissolution of NiCoP NWs and the oxidative re-deposition of dissolved Co and Ni ions, which is based primarily on the anodic bias applied on NiCoP NWs. The well balance of above competing reactions, and local pH on the surface of NiCoP NW modulated by the anodic oxidation can serve to control the anodic electrodeposition and rearrangement of metal ions on the surface of NiCoP NWs, and the immediate conversion into CoNi(OOH). Consequently, the regular hexagonal CoNi(OOH) nanosheets grew around NiCoP NWs. Benefiting from the active catalytic sites on the surface and the sufficient conductivity, the resultant NiCoP@CoNi(OOH) arrays also display good OER activity, in terms of the fast kinetics process, the high energy conversion efficiency, especially the excellent durability. The strategy of in-situ structure reconstitution by electrochemical reaction described here offers a reliable and valid way to construct the highly active systems for various electrocatalytic applications.
深入了解过渡金属磷化物在阳极氧化过程中的结构演变对于理解其析氧反应（OER）机理以及设计高效的过渡金属基催化剂具有重要意义。在此，以垂直生长在泡沫镍上的NiCoP纳米线（NWs）为研究对象，探索阳极氧化过程中的原位形貌和化学成分重构。导致NiCoP转变为分级结构的NiCoP@CoNi（OOH）纳米线的主要因素是两个相互竞争的反应：NiCoP纳米线的溶解以及溶解的Co和Ni离子的氧化再沉积，这主要基于施加在NiCoP纳米线上的阳极偏压。上述竞争反应的良好平衡以及阳极氧化调节的NiCoP纳米线表面的局部pH值，可以控制金属离子在NiCoP纳米线表面的阳极电沉积和重排，并立即转化为CoNi（OOH）。因此，规则的六边形CoNi（OOH）纳米片在NiCoP纳米线周围生长。得益于表面的活性催化位点和足够的导电性，所得的NiCoP@CoNi（OOH）阵列在快速动力学过程、高能量转换效率尤其是出色的耐久性方面也表现出良好的OER活性。这里描述的通过电化学反应进行原位结构重构的策略为构建用于各种电催化应用的高活性体系提供了一种可靠且有效的方法。
