Preparation And Electrocatalytic Properties Of Metal Doped Cobalt Based Phosphide Nanofibers

With the development of society,the human need more energy.Fossil energy is exhausted and its combustion produces greenhouse gas,which does great damage to the environment.In order to change this situation,people have made great efforts.Hydrogen energy,has received much attention,which is renewable clean energy.Hydrogen production from electrochemical water splitting is an efficient,non-toxic and pollution-free method among all preparation methods.Since electrochemical water splitting has large overpotential and consumes more electric energy,catalyst is needed to reduce the overpotential.Also,Pt/C and Ir O₂,as better catalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),respectively,are not widely used owing to their high cost and scarcity.Transition metal phosphides are used as HER and OER catalysts to replace Pt/C and Ir O₂.Because of their poor conductivity and easy agglomeration,we need to find ways to optimize their performance.Therefore,the research of this paper is shown as following::1.Ru and Ni dual-metal doped CoP(Ru,Ni-CoP)porous nanofiber was prepared by high voltage electrospinning,oxidizing and phosphatizing at low temperature.The porous structure increases the specific surface area of the catalyst and exposes more active sites,which is conducive to the transfer of charge and mass.Dual-metal doping can more efficiently modulate the electronic structure than single-metal doping,leading to obviously improving water dissociation capacity and optimizing adsorption energy for different reaction intermediates.As a result,Ru,Ni-CoP porous nanofiber exhibits significantly enhanced bifunctional activity.Furthermore,the electrolytic cell based on Ru,Ni-CoP porous nanofiber only needs low voltage of 1.448 and 1.757 V to achieve 10 and 500 m A cm^-2,respectively in strong alkaline solution,which is significantly superior to Pt/C||Ir O₂ pair.Additionally,the electrolytic cell also exhibits excellent long-term stability at 400 m A cm^-2.This excellent activity and stability at high current density demonstrates the great potential of Ru,Ni-CoP porous nanofiber as high performance bifunctional electrocatalyst for practical application.2.Ni doped CoP₂/C Composites(Ni-CoP₂/C)nanofibers were prepared by electrospinning,carbonizing,vacuum-phosphating,which can increase its conductivity by combining with carbon,and the doping of Ni effectively regulates the electronic structure,thus improving the activities of HER and OER.In the strongly alkaline solution,it has small overpotential,small Tafel slope,and good stability for HER and OER.