Expediting in-Situ Electrochemical Activation of Two-Dimensional Metal-Organic Frameworks for Enhanced OER Intrinsic Activity by Iron Incorporation
Expediting in-Situ Electrochemical Activation of Two-Dimensional Metal-Organic Frameworks for Enhanced OER Intrinsic Activity by Iron Incorporation
复制标题
加速二维金属有机框架的原位电化学活化，通过铁掺入增强 OER 本质活性
DOI：
10.1021/acscatal.9b00072
复制
发表时间：
2019
期刊：
影响因子：
12.9
通讯作者：
Xu Cailing
中科院分区：
文献类型：
--
作者：
Zou Zehua;Wang Tongtong;Zhao Xiaohua;Jiang Wen-Jie;Pan Hairui;Gao Daqiang;Xu Cailing
电化学活化是实现MOF材料原位表面改性而不发生热分解的一种有效、简便的方法。然而，在电化学活化过程中，速率和相关相变对OER本构活性的影响往往被忽视。在此，我们合成了一种具有独特晶体结构的Co-MOF，其中心金属与来自两个水分子和有机连接体的氧原子和氮原子配位。通过在Co-MOF中引入Fe，可以调节中心金属与配位水分子之间的键合强度，从而加速Co-MOF的电化学活化。第一性原理计算表明，可以改变fe - mof中钴的电子态，从而改变吸附中间体的自由能。因此，所获得的电催化剂具有最佳的OER固有活性，在10 mA cm-2时表现出265 mV的低过电位，44 mV dec1的小Tafel斜率，以及40 h的长期电化学耐久性。研究结果有望有助于理解电化学活化的基本原理。
Electrochemical activation is an effective and simple method to obtain in-situ surface modification of MOF materials away from thermal decomposition. However, the impact of the rate and related phase transformation on OER intrinsic activity during the electrochemical activation process is often overlooked. Herein, we synthesized a kind of Co-MOF with a unique crystal structure in which the center metals were coordinated with the oxygen and nitrogen atoms from two water molecules and organic linkers. The bond strength between the center metals and the coordinated water molecules can be modulated by introducing Fe into Co-MOF, causing the expedited electrochemical activation. First-principles calculations suggest the electronic state of cobalt in CoFe-MOF can be modified to alter the free energy of adsorbed intermediates. Therefore, the obtained electrocatalyst possesses the optimal OER intrinsic activity, showing a low overpotential of 265 mV at 10 mA cm–2, a small Tafel slope of 44 mV dec–1, and a long-term electrochemical durability with a period of 40 h. The findings are expected to help understand the fundamental principles of electrochemical activation.