Synthesis Of CuFe₂O₄/Cellulose Nanocrystals Magnetic Composites And Its Catalysis Properties

CuFe₂O₄ nanoparticles?CuFe₂O₄ NPs?possess high electronic conductivity,high thermal stability and high activity,which are widely used in many fields,such as electronics,sensors and catalysts.Along with the strong magnetism and intermolecular diatomic force,CuFe₂O₄ NPs are easily aggregation due to poor dispersity,and consequent restriction of their catalytic performance.To solve this problem,hybrid composites are introduced.Recently,grapheme,reduced graphene oxide,multi-walled carbon nanotubes,and biopolymeric templates have been used for the fabrication of hybrid composites.Cellulose nanocrystals?CNC?are natural cellulose,possessing controlled morphology,high ratio,high surface area and stiffness,Meanwhile,the abundant hydroxyl groups of CNC can gather metal cations.In a word,these properties can provide it as a non-toxic,renewable,good dispersity,high mechanical strength and well good biocompatibility template.In this study,CNC-supported magnetic CuFe₂O₄ NPs catalyst was prepared through a one-step solvothermal method,and three CuFe₂O₄/CNC magnetic composites with different sizes and morphologies were obtained.The morphology,dispersity,partical size,chemical construction,magnetic performance,thermal performance and specific surface area of the three obtained CuFe₂O₄/CNC magnetic composites were also explored.Furthermore,the reaction kinetics and catalytic mechanism were also investigated in detail.All the relative studies are outline as follows:?1?CNC-supported magnetic CuFe₂O₄ NPs catalyst was prepared through a one-step solvothermal method.CNC have abundant hydroxyl groups and possess high ratio and nanoscale size,which make the magnetic composites have high specific surface area and more catalytic sites.Therefore,the catalytic reduction activity of 4-nitrophenol can further improved compared with CuFe₂O₄ NPs.The effects of solvothermal reaction conditions and material ratio were studied.The microstructure,valence bond structure,crystallization property,specific surface area,pore structure,magnetic property,thermal property and element morphology were characterized.What's more,CNC can serve as an excellent absorbent for 4-NP ion with?-?interaction,which further improve catalytic reaction activity.?2?To further improve the dispersibility,morphology and catalytic reduction activity of the CuFe₂O₄/CNC magnetic composites,the hollow CuFe₂O₄/CNC composites are synthesized by using NH₄Ac as alkali source in the solvothermal method.Compared with stuff CuFe₂O₄/CNC composites,the hollow CuFe₂O₄ NPs are hollow sphere shaped with the diameter of about 300nm,the monodispersed CuFe₂O₄ NPs were immobilized on CNC networks.The effects of CNC and NH₄Ac dosage on the morphology and dispersity of the composites were discussed.The microstructure,thermal properties,valence bond structure,magnetic properties,specific surface area,pore structure and element speciation were characterized.The hollow CoFe₂O₄/CNC composites,NiFe₂O₄/CNC composites,and ZnFe₂O₄/CNC composites were prepared by the same method.The catalytic reduction activities of different hollow binary ferrite/CNC composites were compared.On the same time,the catalytic reduction mechanisms of different hollow binary ferrite/CNC composites were elucidated.?3?To improve the specific surface area and catalytic activity,the magnetic composites with core-shell structure were prepared.The core-shell structured CuFe₂O₄/CNC@Ag@ZIF-8 magnetic composites were prepared by in-situ reduction of Ag nanoparticles and coating a zeolitic imidazolate framework?ZIF-8?layer on hollow CuFe₂O₄/CNC composites.The microstructure,element distribution,valence bond structure,crystallization property,magnetic property,specific surface area and pore structure of the CuFe₂O₄/CNC@Ag@ZIF-8magnetic composites were characterized.Meanwhile,the kinetics and recycling performanceofcatalyticreductionof4-NPbyhollow CuFe₂O₄/CNC@Ag@ZIF-8 composites were investigated.The synergetic mechanism of catalytic reduction of 4-NP by composite materials was explained.