Preparation Of Prussian Blue Analoge Derivative Composites And Their Electrocatalysis For Oxygen Evolution Reaction

Metal-organic framework materials are periodic network structures formed by inorganic metal ions and organic ligands.Prussian blue anologes are formed by the combination of metal ions and cyanide ions.Prussian blue anologes have many advantages in materials design.The morphology is easy to modulate for exposing more active sites;Easy to synthesize through a one-step co-precipitation method by combination of the organic groups and various transition metal ions;The transition metal elements have abundant reserves on the earth.Prussian blue anologes play an important role in the fields of electrocatalysis,metal batteries,energy storage,and drug controlled release.It is easy to modify with C,N,P,S and other atoms,which is suitable for a wide range of applications.However,their shortcomings are small pore size and poor conductivity.Generally speaking,researchers usually pyrolyse prussian blue anologes to break the organic cyanide groups.The carbon and nitrogen sources serve as favorable connectors for electron transport.And prussian blue anologes are converted into metal alloys or metal compounds,which have great potential in oxygen volution electrocatalysis.Therefore,using prussian blue anologes as the precursor to obtain an efficient and low-cost OER catalyst is a promising goal in the future.This paper studies the synthesis of prussian blue anologes materials and their derived composite materials and properties of electrocatalytic OER,and discusses the influencing factors of electrocatalytic efficiency.The specific research contents are as follows:1.We used organic cyanide ions as organic ligands,nickel and iron salts as metal sources to prepare nickel-iron bimetallic nano-cubes by self-precipitation.Using roughened melamine sponge(MS)as the base material,grew the arranged nano-cubes and then etched in a simple ammonia solution.Finally a series of electrocatalytic products(NiFe Cage,NiFeP Cage,NiFe Cage@MS,NiFeP Cage@MS)are obtained by phosphating and calcining in Ar atmosphere.The analysis of NiFeP Cage@MS composition,structural characterization and analysis of electrocatalytic performance test are discussed the effects of different doping,with or without etching,and with or without loaded carbon on the electrocatalytic efficiency of the sample.It concluded that NiFeP Cage@MS has Excellent electrochemical performance,the overpotential was 290 mV at a current density of 10 mA·m-2,the corresponding Tafel slope was 46 mV·dec-1,and it had excellent stability.Its excellent electrochemical performance was benefiting from carbon doping which improved the conductivity of the material,the three-dimensional structure that effectively avoided the aggregation of nanoparticles.Also hollow nanocage particles exposed more active sites than solid particles.2.Using zinc salts as the metal source,synthesizing Zn-Co PBA by selfprecipitation method,then adsorbing nickel ions to obtain microspheres coated with nickel atoms,carbonized in the first step in Ar gas,further phosphating and calcining to obtain Co3ZnC/Ni2P Composite materials.Ni2P-coated Co3ZnC microspheres obtained by doping nickel-phosphorus atoms show excellent OER electrocatalytic performance.Thanks to the synergy between the nitrogen-doped carbon material with good conductivity and the zinc,cobalt and nickel trimetallic ions,the overpotential of Co3ZnC/Ni2P was 300 mV at a current density of 10 mA·cm-2,corresponding to the Tafel slope was 84 mV·dec-1,and exhibited good cycle stability.The 8-hour stability test only reduced by 4%.3.The rod-shaped nickel molybdate precursor was prepared by hydrothermal method,and rod-shaped prussian blue compound was prepared by ion exchange,and then calcined under Ar atmosphere at 350 degrees to obtain nitrogen-doped metal carbide.The preparation of prussian blue analogues using nickel molybdate as a template is of great significance for finding cheap,easily available,and efficient OER electrocatalysts.In addition,the preparation method of this experiment can be extended to the preparation of other carbon-doped electrocatalysts with different structures and properties.FeNi/NC exhibited the most excellent OER electrocatalytic performance.The overpotential was 350 mV at a current density of 10 mA·cm-2,and the corresponding Tafel slope was 76 mV·dec-1.