Application And Research Of Cobalt-based Metal Materials In The Field Of Electrocatalysis

Energy plays an important role in the development of society and influence a number of fields of one country due to the developments of industries and technologies rely on great demands of ennergy,which is hardly fufilled by the original fossil energy.Large consumption of fossil results in energy crisis and the global warming bring potential threat to all the livings in this globe.Thus,the new generation energy with green,renewability will be the focus for the coming decades.Many advanced technologies such as fuel cells,water electrolysis and metal-air batteries meet above requirements and have great potential to solve the energy crisis,electrochemical reactions like oxygen reduction reaction?ORR?,hydrogen oxidation reaction?HOR?and hydrogen evolution reaction?HER?and oxygen evolution reaction?OER?are the key for these novel energy devices.In this study,amorphrous Co₃O₄ porous nanosheets array?a-Co₃O₄ PNAs/CFC?and NiCo layered double hydroxides coated Co-based N-doped carbon polyhedron?Co/NCP@NiCo-LDHs?were synthesized by simple,low-cost and non-polluting methods,which not only realized high-efficiency OER catalytic performance,but also studied the influence of vacancy and heterostructure on catalytic materials.This work provides some new ideas for the preparation of excellent electrochemical catalyst materials.Firstly,this paper proposes a strategy for in-situ anodization to synthesize a-Co₃O₄PNAs/CFC.Compared with its corresponding crystalline state?c-Co₃O₄ PNAs/CFC?,a-Co₃O₄ PNAs/CFC has more Co^?vacancies and oxygen vacancies,which changes the hybrid orbital formed by Co and O.This conclusion was confirmed by means of characterization such as electron paramagnetic resonance,X-ray photoelectron spectroscopy and X-ray absorption fine structure.Thanks to the special chemical structure and three-dimensional layered morphology,a-Co₃O₄ PNAs/CFC exhibits superior OER catalytic activity and stability.Next,NiCo layered double hydroxides?NiCo-LDHs?were grown on the PVP functionalized Co-based N-doped carbon polyhedron?Co/NCP?surface to obtain Co/NCP@NiCo-LDHs with a heterostructure.It was found by means of characterization such as Raman spectroscopy,scanning electron microscopy and transmission electron microscopy that the hydroxides on the surface of Co/NCP@NiCo-LDHs are not only distributed very uniformly,but also have a thinner lamellar structure than the LDHs prepared by conventional methods.Therefore,Co/NCP@NiCo-LDHs possesses more catalytically active sites and lower charge transfer resistance,thus exhibiting excellent OER catalytic performance.