The Construction,Engineering And Properties Of Transition Metal Compound As Electrocatalysts

With the development of society,the traditional fossil fuels are running out,and the rock-ribbed pollution issues caused by fossil fuels become more severely.Therefore,it is urgent to develop new and environmentally friendly fuels.In recent years,the search for green and efficient energy has triggering increasing attention to produce H₂ which is considered as a promising source of energy to substitute to the fossil fuel in the future.Electrochemical water splitting is one of the most attractive technique for H₂ production by transforming electricity energy into chemical energy.There are two half reactions in the water splitting process:hydrogen evolution reaction（HER）and oxygen evolution reaction（OER）.Basically,the anodic four-electron reaction process of OER is slower than that of the two-electron reaction process of HER,leading to high overpotential and the sluggish kinetics.Therefore,it is needed to develop an effective electrocatalyst to improve the energy conversion efficiency.In this paper,transition metal salts such as Fe,Co and Ni were used as reaction materials to prepare LDH materials.The defects,morphology,electronic structure and conductivity of LDH materials are regulated by using different electrodeposition methods,tuning deposition conditions and introducing functional substances were used to optimize.Three efficient transition metal-based LDH bifunctional catalysts were prepared in this paper:First,in order to adjust the morphology,GO-FeNi-LDH with regular morphology supported on nickel foam was obtained by regulating the dosage of GO and the deposition condition by cyclic voltammetry,thus improving the catalytic performance of the material.Second,to improve the conductivity,aqueous solution including Fe,Co salt and aniline as electrolyte,FeCo-LDH/PANI with high defects and high conductivity was fabricated by changing the dosage of aniline monomer.The local generated H⁺from aniline polymerization will etch LDH and lead to the generation of defects,thus,improving the electrocatalytic performance.Third,in order to introduce rich defects,the CeO₂ and FeNi-LDH bybrid was prepared by one-step chronoamperometry method.The prepared CeO₂-FeNi-LDH with lower charge-transfer resistance are originated from electron interaction between the two component.Finally,SEM,TEM,FT-IR,XPS and XRD are used to characterize the morphology and structure of the materials.The electrocatalytic activity,stability and methanol resistance of the materials are characterized by CV,LSV,I-T and EIS.