Nickel-iron layer double hydroxide (NiFe LDH) is deemed as an attractive pre-catalyst to lower the reaction barrier of oxygen evolution reaction (OER). However, the catalytic efficiency of NiFe LDH is always hampered by the slow and incomplete reconstruction during OER process. Herein, a strategy of borate ion (BO₃^3-) regulation is developed to achieve a fast and adequate reconstruction of NiFe LDH. The BO₃^3- is easy to fill the oxygen vacancy in NiFe LDH, which can narrow the band gap of NiFe LDH to realize an efficient reconstruction under OER conditions. DFT calculations demonstrate the enhanced effect of BO₃^3- on adsorption of hydroxyl ion (OH^-) to further improve the OER activity. Sequentially, the BO₃^3- decorated NiFe LDH (NiFeB) shows a desirable catalytic activity for OER with an ultralow overpotential of 201 mV to reach a current density of 10 mA cm⁻², which is 40 mV lower than the overpotential of pure NiFe LDH. Moreover, membrane electrode assembly cell using anodic NiFeB and cathodic Pt/C for water splitting affords a cell voltage of only 2.0 V to drive a current density of 540 mA cm⁻². This work widens the horizon of ion effect on electrocatalysis and offers an effective approach for developing high-active electrocatalysts.

镍铁层双氢氧化物 (NiFe LDH) 被认为是一种有吸引力的预催化剂，可降低析氧反应 (OER) 的反应势垒。然而，NiFe LDH 的催化效率总是受到 OER 过程中缓慢和不完全重建的阻碍。在此，开发了一种硼酸盐离子（BO ₃ ^3-）调节策略，以实现快速和充分的 NiFe LDH 重建。BO ₃ ^3-易于填充NiFe LDH中的氧空位，可以缩小NiFe LDH的带隙，实现OER条件下的高效重构。DFT计算表明BO ₃ ^{3 -}对羟基离子（OH ^-) 以进一步改善 OER 活动。随后，BO ₃ ^3-装饰的NiFe LDH (NiFeB)显示出理想的OER催化活性，具有201 mV的超低过电位，达到10 mA cm ^-2的电流密度，比纯NiFe的过电位低40 mV乳酸脱氢酶。此外，使用阳极 NiFeB 和阴极 Pt/C 进行水分解的膜电极组件电池提供仅 2.0 V 的电池电压来驱动 540 mA cm ^-2的电流密度。这项工作拓宽了离子对电催化的影响范围，并为开发高活性电催化剂提供了一种有效的方法。