Preparation And Performance Of Gold-based Anodic Oxygen-evolving Catalyst

As a green,clean secondary energy source,hydrogen energy has a wide range of sources,high combustion calorific value,and is an ideal energy carrier.Hydrogen production by water electrolysis with the advantage of simple progress,easy operation and clean products,is the most promising technology.However,hydrogen production by water electrolysis has high energy consumption and low efficiency,which greatly limits the development of hydrogen production technology.Water oxidation is known as complex processes and technical bottleneck to achieve this goal,which involved a four-electron-transfer mechanism with concomitant formation of an O-O bond.Therefore,the efficient and stable oxygen evolution catalyst is the key to realize this technology.Gold nanomaterials have been a to be a hot research in the most studied systems,due to its own unique electronic structure,size effect and high dispersion characteristics.At present,the application of gold in the field of water splitting is mainly used as a substrate material or a supported nanoparticle,and produces synergistic effect with other metal oxides to improve water splitting.Nevertheless,a method for in situ preparing gold-based oxygen-evolving catalysts by electrodeposition is rare in the current research.Herein,we prepare a novel gold-based anodic oxygen-evolving catalyst in borate electrolyte.It is used as a substrate material to modify cobalt-nickel,nickel-iron.The structure and morphology of catalysts is analyzed by XRD,TEM,SEM,and the components and valence is analyzed by EDS and XPS.The performance of the gold-based catalysts is expressed by a cyclic voltammetric method,a potentiostatic method and a linear scanning voltamametric method.The particular research content can mainly divided into the following three parts:1.In potassium tetraborate system,a novel gold-based anodic oxygen evolution catalyst was successfully prepared by the constant potential method.Through a series of analysis,it was determined that the active component of the catalyst is Au?III?.The optimal catalyst deposition amount was determined by deposition different coulomb amount of the catalyst.The oxygen-evolving overpotential is 315 mV at 1 mA/cm² and a Faradaic efficiency is 90.43%.2.The gold-based anodic oxygen evolution catalyst was used as the substrate material,and the CoNi@Au composite catalyst was successfully prepared by the potential pulse.The results show that the existence of the substrate affects the morphology and electronic structure of the upper metal,which further affect the catalytic performance of the composite catalyst and achieve synergistic catalysis.The substrate significantly increases the current density of CoNi and reduces its overpotential.3.Ni Fe@Au composite catalyst was successfully prepared by current pulse,and the water oxidation performance of NiFe was improved greatly.The maximum current density of NiFe@Au composite catalyst is 8.7 mA/cm² in 0.1M K₃PO₄ solution,which is higher 2.3 mA/cm² times than pure NiFe alloy.