Preparation And Application Of Fe₂P/Co Embedded In Porous Carbon As Trifunctional Electrocatalyst

The development of renewable energy technology is inseparable from electrocatalysts,but the scarcity and high price of precious metals severely hinder their commercial application.The multifunctional electrocatalyst can realize multiple electrocatalytic processes in the same energy conversion device,which is beneficial to simplify the system construction and reduce the cost.Therefore,developing low-cost,high-efficient,non-precious metal electrocatalysts with trifunctions of ORR,OER and HER simultaneously is of great significance.In this paper,an efficient trifunctional electrocatalyst was prepared for the first time using the inexpensive metal-organic small molecule 1,1’-bis（diphenylphosphino）ferrocene（DPPF）as Fe and P sources.This paper mainly focus on following contents:1)DPPF and zinc-cobalt bimetallic ZIF precursors（DPPF@Zn Co-ZIF）were prepared by hydrothermal method.Fe₂P/Co embedded in porous carbon was obtained after carbonization of DPPF@Zn Co-ZIF precursors at different temperatures.During pyrolysis,DPPF served as both Fe and P sources to simplify the synthesis process.Zn would be evaporated to produce abundant micropores and mesopores.It is found that 950℃is the optimal temperature（Fe₂P/Co@NPC）with excellent trifunctional activity for ORR,OER and HER.The ORR half-wave potential of Fe₂P/Co@NPC catalyst in 0.1 M KOH solution is 0.876 V,the overpotential for OER/HER is 331/235 mV at 10 mAcm^-2.2)Based on the above studies,in order to further explore the reasons for the high performance of Fe₂P/Co@NPC catalysts,Co@NC and Fe₂P@NPC were synthesized via similar procedure without adding DPPF or Co（NO₃）₂·6H₂O,respectively.The synergistic effect of Fe₂P and Co nanoparticles furnish Fe₂P/Co@NPC catalyst with high catalytic activity for ORR,OER and HER.Notably,the Fe₂P/Co@NPC composite nanomaterial has been employed in electrodes for anion exchange membrane fuel cells（AEMFCs）,rechargeable Zn-air batteries and water splitting devices with superior electrochemical activity.Significantly,the Fe₂P/Co@NPC catalyst could be efficiently used as cathode in an anion exchange membrane fuel cell with a peak power density of 1.25 W cm^-2.Furthermore,the as-assembled rechargeable Zn-air battery exhibits the power density of 233.56 mWcm^-2 and a cycle life of 180 h.When used in the overall water splitting,the Fe₂P/Co@NPC electrode delivers a low potential of 1.73 V to drive 10 mAcm^-2 and shows excellent stability after consecutive operation for 60 h.