Study On Composite Modification Of Transition Metal Nanostructured Electrocatalyst And Electrocatalytic Performance Of Water Splitting

With the rapidly declining fossil energy resources and increasingly serious environmental pollution,the exploration of clean and renewable energy sources are impendence.Among alternative,because of the high gravimetric energy density,no generation of catalyst-poisoning species and greenhouse gas,hydrogen energy by electrocatalytic water splitting is regarded as the most appropriate ideal energy sources.Nevertheless,in contrast to the two-electron transfer pathway(HER),the four-electron process(OER)results in high energy barriers,representing a major obstacle for electrocatalytic water-splitting.Therefore,constructing different catalyst systems to improve the oxygen evolution performance in electrochemical process,which is the focus of current research for improving the overall efficiency in the process of electrolytic water.In this paper,the transition metal electrocatalysts with different nanostructures were successfully direct integrated into Ni-Fe foam(NFF)and carbon-based nanofiber(CNF)with large specific surface area,high strength and good electrical conductivity by composite modification the active materials with different benign substrates.The synergistic effect between the active material and the substrate provides a lower interface resistance,which greatly improves the conductivity of the electrode system.Thereby,the OER catalytic activity of the catalyst has been greatly improved.The research contents of this paper are as follows:1.Alloy foam derived Ni0.86Fe2.14O4 hexagonal plates as an efficient electrochemical catalyst for the oxygen evolution reaction.We prepared a three-dimensional(3D)intertwined Ni0.86Fe214O4 hexagonal plate electrocatalyst by seamless growth and direct synthesis on Ni-Fe foam(NFF)via a hydrothermal method at 180℃ and pH=4.In 1 M KOH,the Ni0.86Fe2.14O4/NFF electrocatalyst exhibited excellent OER electrochemical performance(when the current density was 1000 mAcm-,the overpotential was only 320 mV),and 20 h electrochemical stability at the current density of 20 mAcm-2,outperforming commercial RuO2/NFF and other analogs2.Electrospinning-based DNA molecular self-assembled Co2P-Co2N core-shell nanofibers for oxygen evolution reaction.We use phosphate groups on DNA as phosphorus sources to synthesize C02P nanoparticles and successfully integrated the highly dispersed Co2P-DNA(C)@CNF core-shell structure(consists of C02P nanoparticles cores and Co2N shells)nanofibers electrocatalyst by a classical one-step electrospinning method.The Co2P-DNA(C)@CNF nanofiber shows a remarkable OER performance,outperforming that the Co-N@CNF as well as its many counterparts and prominent electrochemical durability.This pave a way to synthesize other transition metal phosphides with high efficiency,and provides multiple possibilities for synthesizing safe,environment-friendly and low-cost electrocatalysts in the future.