Hou Xiaoman, Li Jing, Zheng Jian, Li Luming, Chu Wei
College of Chemical Engineering, Sichuan University, Chengdu 610065, China.
Department of Chemistry, Tsinghua University, Beijing 100084, China.
Dalton Trans. 2022 Sep 20;51(36):13970-13977. doi: 10.1039/d2dt00749e.
The transition metal hydroxide NiFe LDH is a promising oxygen evolution reaction (OER) catalyst. Surface engineering, such as the introduction of oxygen vacancies into NiFe LDH, has been reported to further improve the OER performance; however, searching a facile approach remains an issue. In this work, we report a novel and efficient electrochemical reduction method for introduction of oxygen vacancies into NiFe LDH laminates by applying a constant negative voltage. The results show that the reduced NiFe LDH (denoted as r-NiFe LDH) exhibits enhanced OER performance its counterpart NiFe due to the increase of oxygen vacancy density, the electrochemically active surface area, wetting ability, and the significant electron transfer rate. In 1 M KOH, the r-NiFe LDH shows a high current density of 110 mA cm at 1.60 V ( RHE), which is 2.8 times the current density of NiFe LDH (40 mA cm), as well as the long-term stability of 100 h. This electroreduction method is also applicable to other LDH materials loaded by different current substrates or synthesized by various methods, demonstrating its universality for the enhancement of the OER activity of LDH electrocatalysts.
过渡金属氢氧化物镍铁层状双氢氧化物是一种很有前景的析氧反应（OER）催化剂。据报道，表面工程，如在镍铁层状双氢氧化物中引入氧空位，可进一步提高析氧反应性能；然而，寻找一种简便的方法仍然是一个问题。在这项工作中，我们报道了一种新颖且高效的电化学还原方法，通过施加恒定负电压在镍铁层状双氢氧化物层板中引入氧空位。结果表明，还原后的镍铁层状双氢氧化物（表示为r-NiFe LDH）由于氧空位密度增加、电化学活性表面积增大、润湿性提高以及显著的电子转移速率，其析氧反应性能比其对应物镍铁层状双氢氧化物有所增强。在1 M氢氧化钾中，r-NiFe LDH在1.60 V（相对于可逆氢电极）时显示出110 mA cm的高电流密度，是镍铁层状双氢氧化物电流密度（40 mA cm）的2.8倍，并且具有100小时的长期稳定性。这种电还原方法也适用于由不同电流基底负载或通过各种方法合成的其他层状双氢氧化物材料，证明了其在增强层状双氢氧化物电催化剂析氧反应活性方面的通用性。
