Synthesis Of Spinel Ferrite And Its Gas Sensing Properties

Along with the development of the industry,more and more poisonous and harmful gases emitted into the atmosphere environment,affect people’s health,detect the poisonous and harmful gas have become more and more important,as a result,the gas sensor by academia and industry,more and more attention,however,most of the metal oxide based gas sensor is low detection limit,sensitivity and disadvantages such as poor selectivity of these disadvantages limiting its application in daily life,thus,spinel metal oxide has caused more and more It is concerned that it has a more easily designed microstructure than mono-metal oxides,thus improving its gas-sensitive performance.In this paper in order to enhance the sensor sensitivity,selectivity and lower detection limit as the goal,using solvent hot method Cu Fe₂O₄,Ni Fe₂O₄,Zn Fe₂O₄three different morphology of spinel metal oxide,and as a sensing material gas sensor,composite oxide system studied the influence of microstructure on the sensing characteristics,the main contents are as follows:Using copper acetate and ferric nitrate as raw materials,the cube-shaped Cu Fe₂O₄was prepared by hydrothermal method.The sample was characterized by SEM,XRD,XPS and other techniques to determine its surface morphology and crystal structure.It was found that its diameter was about 1.2μm.And design a comparative experiment to explore the influence of the reaction temperature,reaction time,p H value and other factors on the morphology of the sample.After that,the gas sensitivity of the material was tested,and it was found that Cu Fe₂O₄has the highest response to acetone,and the sensitivity to 1×10^-4acetone at 220°C is9.6,and in subsequent tests,it shows good repeatability and long-term stability.Using nickel chloride and iron chloride as raw materials,multi-porous spherical Ni Fe₂O₄was prepared by combining solvent heat and calcination,and its crystal structure and micromorphism were characterized by several characteristic techniques,and it was found that Ni Fe₂O₄was diameter before calcination.About 250 nm micro-trophies,500°C calcination for the diameter of 170 nm or so of multi-empty micro-balls,and a comparative test to explore the effect of calcination temperature on Ni Fe₂O₄micromorphic appearance,and then the material gas-sensitive performance test,Ni Fe₂O₄,calcined at 500°C,was found to have better sensitivity and response recovery time to acetone.Zinc chloride,iron chloride as raw materials,urea as a solvent,the use of solvent thermal system to prepare the micro-ball structure of Zn Fe₂O₄,SEM to observe its appearance,found that the diameter of the micro-ball is about 110 nm.The hydrothermal temperature,hydrothermal time and solvent system are then explored.The gas sensitivity test results show that Zn Fe₂O₄has the highest sensitivity to acetone at 250°C operating temperature,the response recovery time is 12 s and 20 s respectively,and has good long-term repetition,selectivity and long-term stability,it is a promising acetone sensitive material.