Electrochemical Synthesis And Electrocatalytic Oxygen Evolution Of Heteroatom Doped Cobalt Based Nanomaterials

Under the"Dual-Carbon"goal,the electric-hydrogen coupling system has been considered as the key path to promote the consumption of new energy and achieve the green and low-carbon transformation of energy structure.As an important bridge connecting the transition from traditional energy to renewable energy,the technology of hydrogen production from electrolytic water is the core link in building a clean and efficient sustainable energy system using hydrogen as the medium and realizing the recycling and utilization of hydrogen energy.Reducing the cost of hydrogen production by electrolytic water is essential to popularize it on a large scale,and the cost reduction needs to be achieved through continuous innovation technology.As a semi-reaction of electrolytic water reaction,oxygen evolution reaction（OER）involves complex multi-electron transfer process and exhibits slow kinetics,which has been recognized as a bottleneck limiting the overall energy efficiency improvement of electrolytic water green hydrogen production.Therefore,the design and assembly of cheap,efficient and stable OER catalyst is of great significance for water electrolysis technology.In this paper,a series of nanomaterials with superior OER catalytic performance were prepared by electrodeposition method using the heterostructure construction and heteroatom doping strategy.Moreover,XRD,SEM,TEM,XPS and other characterization methods were used to analyze and study the phase components,microscopic morphology and electronic structure of the materials.And using the LSV,CV,EIS,i-t and other electrochemical testing methods to evaluate the electrochemical properties of the as-synthesised samples,further discussing the reasons for the enhancement of catalytic activity of the materials.This work contributes to the understanding of the mechanism of doping on the adjustment of catalyst performance,providing a reference direction for the design and fractional construction of the catalytic properties of efficient electrolytic water oxygen evolution reaction with spatial structure advantages,and expanding the application of electrodeposition in the field of nanomaterials synthesis.Specific research contents are as follows:（1）Mn-doped crimp-nanosheets Mn-Co_0.85Se/Ni Se₂/NF was synthesized on Ni foam by the electrodeposition combined with chemical vapor deposition.The crisscrossing and curling structure of nanosheets provides a dense pore structure,large electrochemical surface area and sufficient gas diffusion channels.The synergism between Ni,Co,Mn and the strong interaction at the phase interface ensures the excellent OER catalytic performance of Mn-Co_0.85Se/Ni Se₂/NF,which requires only 175 m V overpotential to reach a current density of 10 m A·cm^-2 under alkaline conditions of 1 M KOH.This work may provide a feasible strategy for the design of efficient selenide-based oxygen evolution reaction catalysts（2）P-doped P-Fe OOH@Co C₂O₄/NF catalyst was synthesized by using the electrodeposition to modify the structure of Co C₂O₄ micron-rod which loaded on the Ni foam.The ultrathin Fe OOH nanosheets significantly increased the specific surface area of Co C₂O₄,enhanced the nanometer size effect of the catalyst,and the conversion of Co species to Co OOH was accelerated through the co-catalytic components Fe OOH and P-doped.P-Fe OOH@Co C₂O₄/NF catalyst showed superior OER catalytic performance at different current densities of 10/100/200 m A·cm^-2,which could be reached at only 211/264/295 m V overpotential.This work provides a simple scheme for the optimization of OER catalytic performance of oxalate and is expected to broaden the research idea of oxalate in electrochemical direction.（3）Ce-doped Ce-Co（OH）₂@Cu（OH）₂/CF catalyst was synthesized by impregnation and electrodeposition with mild conditions of room temperature and pressure.For Ce-Co（OH）₂@Cu（OH）₂/CF,Co（OH）₂ nanorods were combined with the Cu（OH）₂ nanorods with excellent electrical conductivity to optimize the microstructure and the number of active sites,besides,the doping of Ce effectively adjusted the electronic structure of Co sites.Thus,under the basic condition of 1 M KOH,Ce-Co（OH）₂@Cu（OH）₂/CF can reach the current density of10 m A·cm^-2 with only 206 m V overpotential.This work provides a new idea for the combination of heterogeneous structures and doping engineering,providing an example reference for the development of Co-based catalysts.