Preparation And Gas Sensing Properties Of Y-Zn₂SnO₄/SnO₂ Microcubes And Pr-BiFeO₃ Hollow Nanofibers

In order to overcome the increasingly serious air pollution,it is generally believed that gas sensors play an irreplaceable role in the real-time and accurate detection of different toxic gases.Composite metal oxides composed of two?or more?metals have become hot topics in the field of materials science due to their unique morphology and excellent physicochemical properties.Sensors made of doped modified composite metal oxides are relatively less of a concern than the reported single metal oxides.Herein,complex metal oxide Zn₂SnO₄,BiFeO₃ and metal oxides SnO₂ had been chosen as main research material.Meanwhile many approaches had been adopted to enhance the gas sensing performance,including synthesis hollow/porous structure,rare earth elements doping,noble metal modifying and formation heterostructure.These strategies positively influenced the morphology,specific surface area,grain size and photoelectric properties of the materials,we ultimately realized the sensing performance improvement.This work was divided into the two parts.?1?ZTO/SnO₂ and Y doped ZTO/SnO₂ microcubes have been synthesized via a hydrothermal route.Compared with sensors based on ZTO/SnO₂ microcubes,the Y doped ZTO/SnO₂ microcubes had an optimum sensing performance to 100 ppm formaldehyde?HCHO?,for instance lower working temperature?210°C?and better response?46.07?.The response recovery time is 21/17 s.The enhancement of its gas sensitivity is mainly attributed to the fact that Y ion doping provides more active sites and reduces the band gap value.In addition,the heterojunction between Zn2SnO4 and SnO2 is also an important reason for the improvement of gas sensitivity.?2?The Pr doped BiFeO₃ nanofibers were prepared through single-capillary electrospinning method.We tested its crystal structure,morphology and chemical composition using various characterization methods.Gas sensing tests showed that the optimum operating temperature of the Pr-doped BiFeO₃ hollow nanofiber sensor was190°C.The response to 50 ppm formaldehyde was 17.6 and the response recovery time was 17 and 19 s.The excellent gas sensitivity is mainly attributed to the fact that Pr ion doping provides more oxygen vacancies and the hollow nanofiber structure provides a larger specific surface area.