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 η = 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.

NiFe层状双氢氧化物（NiFe-LDH）已被广泛接受为氧释放反应（OER）的有希望的催化剂候选物。近来，已将Co原子掺入NiFe叠层中被认为是增强OER活性的有效方法，但很少研究其作用。在本文中，使用密度泛函理论加U（DFT + U）计算来评估在NiFe-LDH催化剂中引入二价Co ²⁺或三价Co ³⁺后的OER热力学，以及由此引起的位点敏感性。通常，基于计算结果，将Co ²⁺ / Co ³⁺掺入NiFe-LDH中可以调节金属位点的电子结构，从而降低其OER过电位。而且，Co ³⁺在以上提出的结构中，掺杂的NiFe-LDH具有最低的过电势，η= 0.413 eV。通过共沉淀法制得的掺有Co ²⁺和Co ^3+的NiFe-LDH纳米片充分证明了这一点，方法是：掺杂Co ^3+的NiFe-LDH的OER起始过电为249 mV，Co ^2的为264 mV。⁺掺杂的NiFe-LDH，分别比原始的NiFe-LDH（282 mV）低33 mV和18 mV。这种提高的OER活性归因于在CoO ²⁺掺杂的NiFe-LDH的^* OOH形成步骤和Co ³⁺的去质子化步骤中降低的过电势掺杂的NiFe-LDH，这是其OER工艺的潜在限制步骤。这项工作应为将来设计更高效的基于NiFe的氧气析出电催化剂提供启发。