Construction of hierarchical Mn-CoO@Fe(OH)3 nanofiber array for oxygen evolution reaction

Due to the high price of noble metal catalysts, there is an urgent demand for the development of inexpensive and earth-abundant electrocatalysts for the oxygen evolution reaction (OER). It is known that a hierarchical structure can effectively increase the catalytic area and improve the charge transfer of the OER electrocatalyst, while Ni foam is known to be an advantageous substrate. Therefore, in this work a hierarchical Mn-CoO@Fe(OH)(3) nanofiber array was prepared by the hydrothermal reaction and immersion at room temperature, and X-ray diffraction and transmission electron microscopy measurements were carried out to characterize the microstructure of the nanofiber array. X-ray photoelectron spectroscopy was used to analyze the valence states of the array, demonstrating the successful synthesis of the Mn-CoO@Fe(OH)(3) nanofiber. As the catalyst for OER, the Mn-CoO@Fe(OH)(3) nanofiber array showed a low overpotential of 195 mV at a current density of 10 mA cm(-2) as well as high stability (80 h) in the durability test. This work demonstrates the feasibility of the design of hierarchical nanostructure electrodes with high electrochemical performance for catalytic reactions and various battery applications. (C) 2020 Elsevier B.V. All rights reserved.