Synthesis And Performance Of Nickel Ferrite Photocatalytic Material

Photocatalysis is the perfect way to treat wastewater,which not only utilizes solar power,but also no toxic by-product generates.Since the discovery of TiO₂ using for water photolysis,semiconductor materials have been extensively studied in the field of photocatalysis.Magnetic ferrite materials have been applied in the field of photocatalysis due to their magnetic properties,Among these ferrite materials,NiFe₂O₄ is a very important spinel ferrite material.The band gap of NiFe₂O₄ is 1.7eV,as photocatalyst,absorbing visible-light,therefore the sunlight utilization ratio will improve significantly,simultaneously the magnetism of NiFe₂O₄ can resolve the problem of recycling.To the date,from the research of NiFe₂O₄ photocatalytic degradation,it is obvious to find NiFe₂O₄ directly degrades contaminant next to nothing.In this work,putting the template way to use,porous NiO,Fe₂O₃ are received,experimenting the photocatalytic degradation.Porous NiFe₂O₄ is prepared via the template way in different temperatures,studying the effect of temperature on the photocatalytic activity of NiFe₂O₄.The effect of template method,hydrothermal method and sol-gel method on the photocatalytic properties of NiFe₂O₄ samples is researched.Attempting to optimize the photocatalytic degradation of porous NiFe₂O₄ by loading with Bi₂O₃.Prime experiment contents and results:1.NiO and Fe₂O₃ are prepared by using cotton fiber as template,studying the photocatalytic properties.The photocatalytic degradation rates of NiO and Fe₂O₃ samples are 28%,63%,the adsorption rates of NiO and Fe₂O₃ samples are 24% and 46%.The experimental data tells that the Fe₂O₃ sample has the best photocatalytic degradation rate.2.Porous NiFe₂O₄ is prepared via the template way in different temperatures（400℃,500℃,600℃）.According to the experimental data,the adsorption rate of the samples is 41%,33% and 29% at 400℃,500℃,600℃;the photocatalytic degradation rate of the samples at 400℃,500℃,600℃ is 63%,92% and 90%.The specific surface area of the samples at 400℃,500℃,600℃ is 9.38 m2/g,12.61 m²/g,7.21 m²/g.The sample of 500 ℃ has best photocatalytic degradation rate,indicating that the moderate crystallinity,specific surface area and adsorption rate can improve the photocatalytic degradation rate.3.Porous NiFe₂O₄ is prepared via the template way,comparing to the sample from hydrothermal and sol-gel process.According to the experimental data,the photocatalytic degradation rates of the samples obtained by hydrothermal method,sol-gel method and template method are 23%,69% and 92%,respectively;the adsorption rate of the samples is 23%,29% and 33% by hydrothermal method,sol-gel method and template method;The specific surface area of the samples obtained by hydrothermal method,sol-gel method and template method is 55.6 m²/g,3.59 m²/g,12.61 m²/g.The samples obtained by sol-gel method and template method are porous materials,while the average pore size of hydrothermal samples is 12.4nm,which belongs to mesoporous materials.The sample of 500℃ has best photocatalytic degradation rate,suggesting the moderate specific surface area,adsorption rate and pore size can improve the photocatalytic degradation rate.4.Preparation of α-Bi₂O₃ by direct calcination and porous NiFe₂O₄ loading the α-Bi₂O₃.According to the experimental data,α-Bi₂O₃ was not loaded onto porous NiFe₂O₄.Pure porous NiFe₂O₄（92%）was 51% higher than that of photocatalytic degradation of α-Bi₂O₃（41%）loading onto porous NiFe₂O₄,indicating that the larger particle size of α-Bi₂O₃ can not form an effective heterogeneous structure with porous NiFe₂O₄,which leads to the decrease of photocatalytic degradation rate.Hydrothermal preparation of small particle size β-Bi₂O₃ and porous NiFe₂O₄ loading with β-Bi₂O₃,forming β-Bi₂O₃/Ni Fe₂O₄ heterostructure.The photocatalytic degradation rate of pure porous NiFe₂O₄（92%）was 50% higher than that of β-Bi₂O₃（42%）,showing that the smaller particle size of β-Bi₂O₃ is loaded on the surface of porous NiFe₂O₄,preventing the adsorbance of porous NiFe₂O₄,which leads to the decrease of photocatalytic degradation.