The studies of clad removed fibre optic gas sensor based on mnco2o4 mgco2o4 feco2o4 and nico2o4 nano particles as high performance ethanol and acetone gas detection at room temperature using hydrothermal method

Abstract

consumption, natural observation, monitoring of air and gas quality, especially in the detection of explosion and dangerous gases. These sensors are attracted keenly by researchers to get rid of air pollution and security issues in the world. There are several techniques being used to sense gases such as gas chromatography, FTIR, mass spectrometer, semiconductor gas sensor and so on. Among all, gas sensors based on semiconducting materials provide excellent gas sensing efficiency than gas detecting methods. Recently, fiber optic based chemical sensor method is also used. The operation is simple and easily fetched even in the unstable situation. In the optical fiber based sensor, the transmitted light is used to investigate the properties of the refractive index and retention. On the other hand, metal oxide based gas sensors are facilitated due to their potential applications in monitoring of air and gas quality, detection of gases inflammation, defense security and soon. Gas sensing efficiency is mainly based on the surface of the prepared sensors, morphology, internal structure and surface area. Therefore, several semiconducting based metal oxide sensors such as SnO2, V2O5 and WO3, Sm2O3, Bi2O3 and ZnO are intensively studied and documented in the literatures because of their physico-chemical properties, good conductivity and reasonable oxygen deficiency. Out of all metal semiconductors, ternary metal oxides can be a suitable candidate to combine unique compounds and properties. Recently, spinel cobalt oxides were much considered as gas sensing materials due to their suitable physico-chemical property, mechanical stability and high reactivity to various gas atmospheres relatively at room temperature (RT). Spinel cobalt oxides such as MnCo2O4, MgCo2O4, FeCo2O4 and NiCo2O4 possess enhanced properties such as high conductivity, thermally and structurally stable and good absorption of oxygen on their surfaces. The thesis is organized as eight chapters. The first chapter is the introduction of nanomaterials, their pr