Preparation Of NiFe Bimetallic Oxides And Phosphating Electrocatalysts Supported By Graphene Nanosieves And Their Applications In Water Electrolysis

With the rapid development of human society,people's demand for energy is increasing day by day.The traditional three fossil energy sources,oil,coal and natural gas,are excessively exploited and utilized,which not only causes serious environmental problems,but also threatens the national energy security.Therefore,the development of new renewable energy is of vital importance.Therefore,researchers are focusing more and more on the development of new energy conversion technologies,among which electrolysis of water is an efficient and reliable technology.The converted hydrogen energy has the characteristics of high energy density and no pollution to the environment in the combustion process.Oxygen evolution reaction?OER?is the bottleneck of water cracking and its rate-determining step.Moreover,OER are not only a half reaction of electrochemical water cracking,but also a key half reaction of metal-air batteries and CO₂ reduction reactions.However,OER four-electron processes?4OH^--4e^-?2H₂O+O₂?are kinetically slow and require catalysts to accelerate reactions and reduce overpotentials for their industrialized use.Until now,the best OER electrocatalysts are usually iridium and ruthenium-based catalysts.However,scarcity and high costs on earth make them unsuitable for industrial use.In this paper,cheap and abundant NiFe bimetallic and graphene as the main raw materials,through the design and preparation of multi-level structure,gradually improve the catalytic activity of electrocatalysts OER,laying a foundation for the application of graphene-supported NiFe bimetallic catalyst in industrial production.The main research contents are as follows:1.Reduced graphene?rGO?was prepared by direct reduction of GO by active metals and loaded with NiFe bimetallic oxides to obtain graphene-supported NiFe bimetallic oxides and study its catalytic activity for OER reactions.2.Put graphene load NiFe double metal oxide in different temperature of high temperature calcination,double metal oxide on the surface of graphene carbon thermal reduction reaction occurs,cribriform structure,the formation of graphene and graphene in 700?when the nano screen load NiFe₂O₄-NiFe core-shell structure,study its catalytic activity of OER reaction,when a current density of 10 cm^-2,the overpotential of 301 mV,Tafel slope of 48 mV dec 1,showing good OER the catalytic performance.3.To 700? for graphene nano screen load NiFe₂O₄-NiFe core-shell structure for phosphating,will happen in the process of phosphating ke kendal effect,the formation of graphene nano screen load of porous nickel iron phosphide catalysts,and study its catalytic activity of OER and its ehrs reaction,when the current density for 10 mA cm^-2,OER the overpotential of 227 mV,Tafel slope in 39 mV dec^-1,its ehrs overpotential of 148 mV,showing excellent OER and its ehrs catalytic performance.In summary,the work of this paper gradually improves the activity of electrocatalytic water decomposition through the design of multi-stage structural materials and the formation of pores by means of the kekendall effect.The activity of the electrocatalyst finally synthesized is even far better than that of commercial RuO₂catalyst and most of the reported non-noble metal electrocatalysts.This provides a new idea and method for developing high efficient,stable and economical electrocatalysts.