A High Surface Area Ni–Fe Layered Double Hydroxide for Electrocatalytic Water Oxidation Reaction

For water electrolysis, the energy loss at the anode is significant because water oxidation requires four-electron transfer [1]. Therefore, it is highly desirable to design efficient oxygen evolution reaction (OER) catalysts and ensure their assembly into practical OER electrodes. Layered double hydroxides (LDHs) are anionic clays, which are made of layers of trivalent and divalent metal cations connected to the OH- anions, with interlayer anions carbonate and nitrate inserted between the layers [2,3]. LDH has been used in a variety of areas, including but not limited to catalysis, energy storage, drug or gene delivery, water treatment, etc [4,5]. In this study, we report a simple hydrothermal method to prepare a high surface area Ni–Fe layered double hydroxide (LDH) assembled by nanosheets by using nickel and iron salts as the only starting materials. The obtained materials were characterized using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and BET. The NiFe-LDHs were then used as the efficient electrocatalyst materials for water oxidation. In this condition, the component NiFe-LDH synthesized hydrothermal method displayed improved electrocatalytic activity in comparison with other component LDHs due to the high surface area which enhanced the conductivity of the synthesized LDH. Furthermore, the Ni–Fe LDH material reported herein might be employed as a promising noble-metal-free water oxidation catalyst to replace the IrOx material—the state-of-the-art water oxidation catalyst.