Morphology Regulation And OER Performance Of Nickel-iron Oxides And Hydroxides

In the 21st century,with the rapid development of science and technology,people's living standards are becoming higher and higher,and the demand for energy is also growing.However,the three traditional fossil energy sources?coal,oil and natural gas?are not renewable,and their large-scale use has caused more serious environmental problems?such as greenhouse effect,acid rain,photochemical smog,etc.?,so it is urgent to develop and utilize efficient and clean new renewable energy sources.Electrochemical decomposition of water is one of the most promising technologies for large-scale energy storage,and because of the complex kinetics of four-electron transfer in the process of water electrolysis,as well as the catalytic interface resistance and the internal resistance of the catalytic material,the passing point in the oxygen evolution process is high,which limits the commercial application of most materials.At present,the commercial electrocatalytic oxygen evolution materials are mainly precious metals and their oxides,such as Ru O2 and Ir O2,and the precious metals like Pt,etc.These precious metals have high catalytic activity,but the price is very expensive,which limits their application in industry.Therefore,the development of low-cost and resource-rich transition metal-based materials has attracted extensive attention of researchers.Transition metal oxides and hydroxides materials,due to their unique crystal structure and unique physical and chemical properties,are more likely to improve the OER properties of materials.In this paper,the Ni Fe system was selected to explore the effects of two strategies on the oxides and hydroxides of this type of catalyst through the design of the material morphology and the modification of the components.In this paper,the combination of soft template method and solution p H value regulation was used to slow down the crystallization of Ni Fe oxides and hydroxides.The oxides of Ni Fe with high specific surface area of topological structure were synthesized at the p H value of weak acid,and the hydroxides of Ni Fe with hydrotalite coating were synthesized at the p H value of weak base.Due to the synergistic effect of bimetallic cations and the presence of porous structures,the degree of exposure of active sites is greatly increased,which greatly increases the oxygen evolution performance of the materials.In this paper,soft template method combined with p H value regulation was used to synthesize thin slice Ni Fe LDHs with good dispersion under weak alkaline condition with template agent,and 0D nanoparticle oxide of topological structure Ni Fe was synthesized under weak acid condition,and mesoporous Ni Fe LDO was obtained by roasting Ni Fe LDHs.LDHs forms LDO after roasting at 350?.The mesoporous structure is more obvious in LDO materials.And when Ni:Fe is 4:1,Ni4Fe1 LDO has 252 m V overpotential,which is nearly 500 m V less than the sample before calcination.They have 72 m V dec^-1 the Tafel slope,and R_ct of 80?is 2.01%before roasting.Compared with LDHs,LDO has better OER electrocatalytic performance.