Preparation Of Metal Oxide/Graphene/Carbon Nanotube Complex And Research On Its Electrocatalytic Properties

Oxygen electrode electrocatalysts is one of the main technical bottlenecks restricting the development and application of metal-air secondary battery and fuel cell.Although Pt and its alloys have good oxygen reduction electrocatalysis performance,IrO₂ and RuO₂ are the best electrocatalysis for oxygen evolution reaction,Nonetheless,they are limited for spread commercial applications of the fuel cell and metal-air secondary battery because of high cost.In recent years,non-noble metal catalysts and carbon nanomaterials with mixed elements have become the research focus of oxygen electrode catalytic materials.This paper work aimed at developing Fe,Co compounds/carbon nanomaterials used as bifunctional electrocatalysts for the oxygen electrode material.We prepared graphene,nitrogen doping carbon nanotubes,Co_5.84Fe_2.16OH₁₆（CO₃）_1.08/graphene and the plasma processing CoFe₂O₄/graphene composites and investigating their structure and electrochemical properties.The main contents and results are summarized as follows:1)The Fe and Co compounds/RGO prepared by hydrazine hydrate co-reducing precipitation have good bifunctional electrocatalysts for oxygen reduction catalytic and oxygen evolution reaction.XRD showed that is Co_5.84Fe_2.16OH₁₆（CO₃）_1.08/RGO with hexagonal system.Co_5.84Fe_2.16OH₁₆（CO₃）_1.08/RGO with specific surface area of73.84 m²/g.2)The main components of CoFe₂O₄/RGO samples obtained by plasma treatment are CoFe₂O₄,CoO and graphene.CoFe₂O₄,CoO has the very good synergy on the oxygen electrocatalysts,and the limiting current density of oxygen reduction reaction changes from-4.258 mA/cm²before treatment to-5.038 mA/cm²after plasma treatment,which increases by nearly 25%.And still can maintain oxygen reduction reaction and oxygen evolution reaction catalytic activity.CoFe₂O₄/RGO composite with NCNTs,can effectively improve the oxygen reduction catalyst performance,the oxygen reduction initial potential decreased 110 mV,oxygen evolution initial potential decreased 88 mV,but the oxygen reduction reaction and oxygen evolution reaction current density are attenuated.3)Compared with the high-temperature thermal annealing method,the plasma treatment is characterized by high efficiency,rapidity,and low temperature,which can effectively avoid the phenomenon of agglomeration of the metal oxide under high temperature environment,and preserve the integrity of the graphene structure.CoFe₂O₄/RGO specific surface area of 97.21 m²/g compared with high temperature heat treatment to get the sample of the larger specific surface area of 50.16 m²/g.