Zhou Tingxi, Jing Yike, Yang Yang, Yang Fei, Yi Xuesong, Sun Wei
Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Environmental Science and Engineering, Hainan University, 58 Renmin Road, Haikou, 570228, P. R. China.
Small. 2025 Jan;21(4):e2409374. doi: 10.1002/smll.202409374. Epub 2024 Dec 8.
The NiFe-oxy/hydroxides (NiFeOH) have emerged as promising candidates for alkaline oxygen evolution reaction (OER) but suffer from irreversible metal dissolution to pose a great challenge to long-term stability. Here, a self-supported electrode of NiFeOH/FeNiO/SS-A (substrate-etched stainless steel, SS-A; interlayer-amorphous FeNiO oxide; catalytic layer-amorphous NiFeOH) is fabricated and presents rare self-healing property of surface cracks, as well excellent activity and stability. It is found that crack repair is driven by the redeposition of dissolved Fe and Ni ions from the amorphous interlayer involved in the OER process because no similar behavior is observed in Fe-free and crystalline interlayer-supported NiFeOH. Moreover, the repair performance is dependent on current density and electrolysis time, with 71% of surface cracks being repaired after 72 h operated on an industrial level of 500 mA cm. It needs to be emphasized that the irreversible dissolution of Fe and Ni from the catalytic layer of NiFeOH still occurs but is effectively suppressed. It is demonstrated that the construction of an amorphous FeNiO oxide interlayer in self-supported electrodes plays an important role in improving the stability and is expected to open up an opportunity for the design and develop highly efficient and durable alkaline OER catalytic electrodes.
镍铁羟基氧化物（NiFeOH）已成为碱性析氧反应（OER）的有前途的候选材料，但存在不可逆的金属溶解问题，这对长期稳定性构成了巨大挑战。在此，制备了一种自支撑电极NiFeOH/FeNiO/SS-A（基底蚀刻不锈钢，SS-A；中间层非晶态FeNiO氧化物；催化层非晶态NiFeOH），该电极表现出罕见的表面裂纹自修复性能，以及优异的活性和稳定性。研究发现，裂纹修复是由参与OER过程的非晶态中间层中溶解的Fe和Ni离子的再沉积驱动的，因为在无Fe和晶体中间层支撑的NiFeOH中未观察到类似行为。此外，修复性能取决于电流密度和电解时间，在500 mA cm的工业水平下运行72小时后，71%的表面裂纹得到修复。需要强调的是，NiFeOH催化层中Fe和Ni的不可逆溶解仍然会发生，但得到了有效抑制。结果表明，在自支撑电极中构建非晶态FeNiO氧化物中间层在提高稳定性方面起着重要作用，有望为设计和开发高效耐用的碱性OER催化电极开辟机会。
