| The rapid economic development of modern society has brought the increasing energy demand.Because of its non-renewable nature and the environmental pollution caused by traditional fossil fuels,it is urgent to develop low-cost,sustainable and efficient energy resources.Due to its high energy density and environmental friendly,hydrogen gas stands out among many new energy sources and becomes an ideal substitute for fossil fuels.Electrolytic water technology can produce hydrogen with zero carbon content,renewable and high purity,so it plays an important role in renewable energy system.The anodic oxygen evolution reaction in electrolytic water process leads to slow reaction kinetics due to the complex four electron transfer mechanism,which becomes the bottleneck restricting the development of electrolytic water.In order to improve the efficiency of oxygen evolution reaction,it is necessary to develop highly efficient oxygen evolution catalysts to reduce the reaction energy barrier.While noble metal catalysts with excellent performance in electrolytic water not only have low reserves and high price,but also have poor stability in the reaction,it is of great significance to find non-noble metal catalysts with abundant reserves,low price,high activity and stability as electrode materials.This paper mainly uses transition metal manganese elements as the center to design polymetallic composite oxide catalysts.The morphology and composition of catalysts are controlled by the proportion of raw materials,and their application in oxygen evolution reaction is studied by electrochemical performance testing.The main research contents are as follows:（1）Three-dimensional arrays of iron-nickel-manganese ternary metal nanosheets（Mn-Ni Fe2O4/NF）were prepared on nickel foam by one-step hydrothermal method,the nanosheets are arranged vertically staggered on nickel foam to obtain higher surface area and provide sufficient active sites for oxygen evolution reaction.The high electrical conductivity of nickel foam and its interaction with nanosheets can effectively accelerate the charge transfer in the reaction and improve the oxygen evolution efficiency.Mn-Ni Fe2O4/NF exhibits superior catalytic performance than Mn CO3/NF and Ni Fe2O4/NF,with an overpotential of only 240 m V,and a Tafel slope of 78.9 dec-1at a current density of 100 m A cm-2,which is inextricably linked to the synergistic effect between the three metals.（2）The three-dimensional branchedγ-Mn OOH precursor was synthesized by a simple hydrothermal method,and then the Co OOH nanoparticles were successfully loaded onγ-Mn OOH precursor through the reduction-oxidation process of Co2+ions in the precursor solution.The Co/Mn molar ratio was modulated to obtain theγ-Mn OOH/Co OOH-0.1（B-MCO-0.1）with the optimal performance.At a current density of 10 m A cm-2,the overpotential of B-MCO-0.1 is only 313 m V,Tafel slope is87 m V dec-1,and it also has an excellent stability.The three-dimensional structure ofγ-Mn OOH and the smaller particle size of Co OOH in B-MCO-0.1 make the catalyst has a large specific surface area,and the strong solid-solid interface interaction betweenγ-Mn OOH and Co OOH provides a guarantee for the rapid electron transport. |
