Study On Synthesis And Electrocatalytic Properties Of Transition Metal Phosphides

The large-scale consumption of traditional fossil fuels aggravates the energy crisis,leading to global warming and environmental pollution.Therefore,the development of green,clean and sustainable new energy sources is an urgent necessity.As a new energy carrier with great potential for development,hydrogen energy has a high energy density and the product of combustion is only water,with no by-products,and has attracted much attention around the world.However,hydrogen does not exist in nature and needs to be produced from various hydrogen-containing resources by various technologies.Among them,the electrolysis of water is the most economical way to produce the purest hydrogen gas.This method has received extensive attention due to its advantages of no pollution,high purity of the generated gas,and strong stability.Electrolysising water contains two half reactions,oxygen evolution reaction（OER）occurs at the anode and hydrogen evolution reaction（HER）occurs at the cathode.However,the low electricity utilization rate greatly limits its wide application.The development of efficient and stable electrocatalysts has become a problem that must be solved in this field.Although noble metal catalysts have strong activity for electrolysising water,their durability,scarcity and cost problems seriously hinder their commercial applications.Therefore,it is of great significance to develop low-cost,high-activity and stable non-precious metal electrocatalysts.This work mainly focus on the design and synthesis of transition mental phosphide electrocatalysts with outstanding perperties for OER and HER.Meanwhile,these catalysts were used in the installation of hydrogen gas produced by electrolysising water.The main contents are as following.（1）3D Co P@MWCNTs composite catalysts were synthesized by using hydrothermal method and phosphating method,compared with 1D Co P@MWCNTs,it can be found that MWCNTs is easy to agglomerate on the surface of 1D Co P rods,while MWCNTs uniformly penetrates into 3D Co P nanorods,exposing more electrocatalytic active sites.The 3D Co P@MWCNTs catalyst was coated on the surface of glassy carbon electrode,it exhibits remarkable catalytic performance for OER,with an overpotential of 290 m V at10 m A cm^-2 in 1 M KOH aqueous solution.Meanwhile,it exhibits excellent HER electrocatalytic performance in acidic electrolytes,and the overpotential is 208m V at the current density of 10 m A cm^-2;finally,the 3D Co P@MWCNTs catalysts were applied as anode and cathode catalysts for water electrolysis,the current density of 10 m A cm^-2 werw obtained as the potentials was 1.68 V in an alkaline medium.Meanwhile it also exhibited excellent electrocatalytic stability.（2）The Mo-doped Mn P nanosheet catalyst（Mo-Mn P）were synthesized by using hydrothermal method and phosphating method,which exhibits excellent selectivity for oxygen evolution and chlorine inhibition eectrocatalytic performance in seawater system（1.0 M KOH+0.5 M Na Cl）,As the current density was 100 m A cm^-2,the overpotential of OER only 300 m V.