Electrocatalytic Properties Of Carbon-Based Phosphide Composite In Electrode Reaction

With the concept of sustainable development getting popular,how to balance the relationship between energy economy and environment and promote the coordinated development of the three has become a common concern of the whole society.Hydrogen（H₂）is in line with the needs of the times because of its high energy density,friendly environment and high safety.However,the conventional hydrogen production method needs to consume a great amount of energy and high cost,which greatly limits the application of hydrogen energy.Electrochemical splitting of water is an effective hydrogen production method.When the water molecules are splitting into H₂ and O₂,two semi reactions are involved,named the HER reaction（Hydrogen Evolution Reaction,HER）of cathode and the OER reaction（Oxygen Evolution Reaction,OER）of anode.In addition,OER reaction plays an irreplaceable role in fuel cell and metal air cell.Both of these semi reactions involve the transfer of electrons,which are called uphill process in electrochemistry,which is difficult to react.The noble metal catalyst has excellent electrocatalytic properties in the water splitting for HER reaction and OER reaction.However,the precious metal catalyst has the disadvantages of highly cost,scarcity and instability in electrolyte.Therefore,developmenting of high efficiency,safety,stability and low price electric catalysts for HER reaction and OER reaction can reduce the overpotential（η）of HER reaction and OER reactionand Tafel slope are urgent problems.In this paper,nitrogen-containing graphene was used as carrier,used a simple one-pot synthesis method,and then a high-temperature roasting method used to prepare an efficient ternary phosphide electrocatalyst.The main research contents are as follows:（1）Firstly,cobalt chloride hexahydrate（CoCl₂?6H₂O）,ferric chloride hexahydrate（FeCl₃?6H₂O）and copper chloride dihydrate（CuCl₂?2H₂O）were used to provide non-noble metal species.graphene（GO）was used as the carrier,The metal ions Co²⁺and ligand C₄H₆N₂ were highly coordinated to form MOF ZIF-67.After that,high temperature roasting and high temperature phosphating were carried out in the tubular furnace to prepare excellent HER performance FeCoCuP@NC electrocatalyst.To reach a current of10 mA cm^-2,FeCoCuP@NC required overpotential of 80 mV and 169 mV in 0.5 mol?L^-1H₂SO₄ and 1.0?mol L^-1 KOH solution.The corresponding Tafel slopes were 47.6 mV dec^-1and 48.8 mV dec^-1,respectively.（2）On the basis of the study of（1）,changed the element species of phosphide to prepare excellent composite precursor FeCoNiP@NC active HER and OER electrocatalysts.And the ternary phosphide FeCoNiP@NC was analyzed by morphology characterization,element characterization,electronchemical performance and stability test.To reach a current of 10 mA cm^-2,FeCoNiP@NC required overpotential of 93 mV and 187mV in 0.5 mol?L^-1H₂SO₄ and 1.0?molL^-1 KOH solution for hydrogen reaction.And FeCoNiP@NC required overpotential of 266 mV in 1.0?molL^-1 KOH solution for oxygen reaction.