Understanding the incorporating effect of Co2+/Co3+ in NiFe-layered double hydroxide for electrocatalytic oxygen evolution reaction
Understanding the incorporating effect of Co2+/Co3+ in NiFe-layered double hydroxide for electrocatalytic oxygen evolution reaction
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了解 Co2 /Co3 在 NiFe 层状双氢氧化物中对电催化析氧反应的掺入效应
DOI：
10.1016/j.jcat.2017.11.028
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发表时间：
2018-02-01
影响因子：
7.3
通讯作者：
Duan, Xue
中科院分区：
文献类型：
--
作者：
Bi, Yongmin;Cai, Zhao;Duan, Xue
NiFe层状双氢氧化物（NiFe-LDH）是一种具有良好催化活性的新型析氧催化剂。近年来，在NiFe层压板中引入Co原子被认为是提高OER活性的有效途径，但其作用很少被研究。本文采用密度泛函理论（DFT）+ U方法对NiFe-LDH催化剂中引入二价或三价Co ~（2+）后的OER热力学及由此引起的位敏感性进行了研究。计算结果表明，Co ~（2+）/Co ~（3+）的掺入可以调节NiFe-LDH金属中心的电子结构，从而降低其OER过电位。此外，Co 3+掺杂的NiFe-LDH具有最低的超电势，η = 0.413 eV的上述提出的结构。通过共沉淀法制备的掺入Co2+和Co 3+的NiFe-LDH纳米片充分证明了这一点，Co 3+掺杂的NiFe-LDH的OER起始过电位为249 mV，Co2+掺杂的NiFe-LDH的OER起始过电位为264 mV，分别比原始NiFe-LDH的OER起始过电位（282 mV）低33 mV和18 mV。这种提高的OER活性归因于Co 2+掺杂的NiFe-LDH的 *OOH形成步骤和Co 3+掺杂的NiFe-LDH的去质子化步骤的过电位降低，这是其OER过程的电位限制步骤。这一工作对今后设计更高效的NiFe基析氧电催化剂具有一定的启发意义。(C)2017爱思唯尔公司All rights reserved.
NiFe-layered double hydroxide (NiFe-LDH) has been widely accepted as promising catalyst candidates for the oxygen evolution reaction (OER). Recently, incorporating Co atoms in NiFe laminates has been recognized as an effective way to enhance the OER activity, but their roles have been rarely studied. Herein, density functional theory plus U (DFT + U) calculations are employed to evaluate the OER thermodynamics after introducing bivalent Co2+ or trivalent Co3+ and consequent sites sensitivity in NiFe-LDH catalyst. Generally, based on computational results, incorporation of Co2+/Co3+ into NiFe-LDH could modulate the electronic structure of metal sites and thus reducing their OER overpotential. Moreover, Co3+-doped NiFe-LDH has the lowest overpotential of eta = 0.413 eV among the above proposed structure. This point was fully demonstrated by Co2+ and Co3+-incorporated NiFe-LDH nanosheets made by a co-precipitation method, by showing OER onset overpotential of 249 mV for Co3+-doped NiFe-LDH, 264 mV for Co2+-doped NiFe-LDH, which are 33 mV and 18 mV lower than that of pristine NiFe-LDH (282 mV), respectively. Such improved OER activity were attributed to the lowered overpotential at the *OOH formation step for Co2+-doped NiFe-LDH and the deprotonation step for Co3+-doped NiFe-LDH, which was the potential limiting step for their OER process. This work should be inspiring for future designing of more efficient NiFe-based oxygen evolution electrocatalysts. (C) 2017 Elsevier Inc. All rights reserved.