Engineering a stereo-film of FeNi3 nanosheet-covered FeOOH arrays for efficient oxygen evolution

Abstract

Electrochemical oxygen evolution reaction (OER) can be accelerated by employing transition-metal-based catalysts to obtain the desired activity and durability. Considering the promoting effect of the electrode structure on catalyzing OER, a stereo-film on carbon cloth comprising FeNi₃ nanosheet-covered FeOOH (F@FeNi₃-CC) was engineered by the hydrothermal reaction and subsequent synchronous electrodeposition of Fe and Ni ions. In F@FeNi₃-CC, the FeOOH array not only provides the Fe source of FeNi₃ nanosheets during the cathodic electrodeposition, but also functions as the support for the ultrathin FeNi₃ nanosheets. Such a stereo-film with good electrolyte-permeability also offers expedited electrolyte/reactant transmission paths. The tailored FeNi₃ nanosheet offers abundant exposed catalytic sites by virtue of the in situ derived hydroxide layer during anodic oxidation and also acts as the current collector to accelerate charge transport. The F@FeNi₃-CC electrode yields outstanding catalytic activity towards OER in alkaline media, particularly at low potential of 1.50 V and large current density of 100 mA cm⁻², accompanied with the excellent long-term stability. These results are significant for the construction of stereo-film electrodes for various engineering applications.