Sakamaki Aoi, Yoshida-Hirahara Miru, Ogihara Hitoshi, Kurokawa Hideki
Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan.
Langmuir. 2022 May 10;38(18):5525-5531. doi: 10.1021/acs.langmuir.2c00097. Epub 2022 Apr 29.
Electrochemical water splitting is a key technology for the conversion of renewable energy into chemical resources such as hydrogen. However, the oxygen evolution reaction (OER), a half-reaction of water splitting, is so slow that various effective catalysts for the OER have been explored. In this study, we demonstrate a simple and direct process for the synthesis of OER-active NiFe catalysts over electrodes. A NiFe/C catalyst layer was formed on a glassy carbon electrode by simply dropping the catalyst ink containing only metal nitrates and carbon black. The catalyst layer exhibited higher OER performance than the state-of-the-art Ir/C catalyst. The presence of carbon black is essential to enhance the OER activity of NiFe because carbon black helps to disperse the NiFe active sites. Cyclic voltammetry indicated that Ni and Fe are adjacent to each other on the surface of carbon black, resulting in significantly higher activity of NiFe/C compared to those of Ni/C and Fe/C. The effects of the Ni/Fe ratio, amount of carbon black, and type of carbon black on the OER activity of NiFe/C were examined in detail. Furthermore, we discuss the factors that determine the OER performance of NiFe/C.
电化学水分解是将可再生能源转化为氢等化学资源的关键技术。然而，析氧反应（OER）作为水分解的半反应，速度非常慢，因此人们探索了各种用于OER的有效催化剂。在本研究中，我们展示了一种在电极上合成具有OER活性的NiFe催化剂的简单直接方法。通过简单地滴加仅含有金属硝酸盐和炭黑的催化剂墨水，在玻碳电极上形成了NiFe/C催化剂层。该催化剂层表现出比目前最先进的Ir/C催化剂更高的OER性能。炭黑的存在对于提高NiFe的OER活性至关重要，因为炭黑有助于分散NiFe活性位点。循环伏安法表明，Ni和Fe在炭黑表面彼此相邻，这导致NiFe/C的活性明显高于Ni/C和Fe/C。详细研究了Ni/Fe比、炭黑用量和炭黑类型对NiFe/C的OER活性的影响。此外，我们还讨论了决定NiFe/C的OER性能的因素。
