| The imminent shortage fossil fuels and the ever-growing concerns of energy and environmental issues have attracted more attention.The key to solve these problems is to develop new energy instead of traditional fossil energy.In this respect,electrochemical electrolysis of water is considered to be one of the most promising strategies.Hydrogen production by water splitting requires efficient and stable electrocatalysts to effectively improve the kinetics of oxygen evolution reaction and hydrogen evolution reaction.However,the rate of hydrogen production is limited by the high energy barrier of the four protons and electron transfer process of water oxidation during the process of oxygen evolution.Commercial and cheap nickel foam material is widely used as carrier and substrate for electrode materials because of its large specific surface area,high electronic conductivity and ideal three-dimensional opening structure.Based on the above analysis,the design and synthesis of cheap,efficient and stable catalysts is the key factor.Two materials,Co3O4@Ni3S2 and FeCo2O4@Ni3S2 with different structure and layered structure,which are loaded on foamed nickel base materials,are prepared by hydrothermal and calcining methods.The materials were characterized by X-ray powder diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?and nitrogen desorption negative Raman spectroscopy.The Co3O4@Ni3S2 showed a low overpotential,and the overpotential required by the current density of 20 mA cm-22 is 260 mV.The overpotential required by FeCo2O4@Ni3S2 is 231 mV at a current density of 10 mA cm-2.What's more,all of these materials showed good stability in OER.This shows that the Ni3S2 nanomaterial coated on the MCo2O4?M=Co,Fe?can effectively reduce the overpotential and improve the reaction rate.This is mainly due to the synergistic effect between MCo2O4?M=Co,Fe?oxide materials and Ni3S2 nanomaterials. |
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