A Study On Transition Metal Phosphide As Catalyst Of Electrocatalytic Oxygen Evolution Reaction

Nowadays,with the continuous improvement of the industrial level,the large-scale utilization of fossil energy has resulted in a series of problems,such as environmental pollution,energy depletion,etc.Therefore,many scientists are committed to the study of electrocatalytic water decomposition electrode materials to produce high combustion heat value,clean and pollution-free,easy to store and transport hydrogen energy to replace the traditional fossil energy.However,due to the large potential and poor stability in the process of electrocatalytic water decomposition anode material oxygen production,it has gradually become a bottleneck in this field.Therefore,we have synthesized a series of transition metal phosphides by simple solid-phase synthesis of direct elements and argon arc welding technology,and systematically explored the selection of anode materials for electrocatalytic water decomposition under alkaline conditions,the design of new efficient catalytic materials for oxygen evolution reaction and the improvement of catalytic efficiency of oxygen evolution reactionIn the first part,through sorting out the previous research results in this field,and combining with the theoretical calculation of the electronic structure of materials,it is found that there are a lot of Ni-Ni bonds in the structure of nickel based materials and there are Ni-Ni anti bonds below the Fermi level,so the compound has excellent catalytic efficiency and stability for oxygen evolution reaction.Therefore,we studied the oxygen evolution reaction(OER)of nickel phosphide(Ni5P2?Ni3P and Ni5P4)with different structures rich in Ni-Ni bonding.The results of electrochemical tests show that Ni5P2 and Ni3P with Ni-Ni anti bond below Fermi level can maintain high stability while maintaining good catalytic activity for oxygen evolution reaction,and the current density can reach 100 mA·cm-2 with only 340 mV overpotential,and the reaction has been stable for 12 h.In the second part,we designed and synthesized new compounds,and systematically studied their catalytic performance of oxygen evolution reaction.We replaced part of P in Ni5P2 structure with part of Si,and obtained Ni8Si1.5P1.5?Ni8Si2P and Ni31Si12 materials with similar structure.Ni8Si1.5P1.5 showed excellent oxygen evolution reaction at high current density,the current density of 100 mA·cm-2 can be reached at 330 mv and the reaction is stable for 12 hours or even longer.In the third part,in order to improve the properties of the materials,we use part of Ge to replace part of P in Ni8P3 structure,and obtain a new Ni8GexP(1-x)compound,which elongates the Ni-Ni bond in Ni8P3 structure,greatly improving the properties of the materials.At the same time,the incorporation of Fe in the new compound greatly reduces the oxygen evolution reaction potential and improves the stability of the compound at high current density.In the research process,we have tested the materials with high current density,and Ni7FeGeP2 has shown very excellent performance and stability.It is believed that the research can contribute to the large-scale production of catalyst materials for oxygen evolution reaction with low cost,high catalytic activity and high stability.