Simple Synthesis of ZnCo2O4 Nanoparticles as Gas-sensing Materials

Sensor and Transducers 01/2011; 134:95-106.
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    ABSTRACT: Semiconductive nanoparticles of CdFe2O4 were synthesized by a solution combustion technique. This process is a convenient, environment friendly, inexpensive and efficient for the preparation of CdFe2O4 nanomaterial. The synthesized material is characterized by Thermo gravimetric Differential analysis (TG/DTA), X-ray Diffraction studied (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques. Conductance response of the nanocrystalline CdFe2O4 thick film is measured by exposing the film to reducing gases like ethanol, acetone, ammonia, H2S and hydrogen. The sensor exhibited a fast response and a good recovery. The results demonstrated that CdFe2O4 can be used as a gas-sensing material which has a high sensitivity and good selectivity to ethanol gas at 200 ppm.
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    ABSTRACT: Nanocrystalline Zinc oxide powder was prepared by co-precipitation method. Thick films of pure ZnO was prepared by screen-printing technique for sensor application. Different characterization techniques have been employed, such as, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The gas sensing properties were studied towards reducing gas CO. It is observed that the nanoparticles of ZnO show high sensitivity to CO at operating temperature.
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    ABSTRACT: The preparation, characterization and gas sensing properties of pure nanocrystalline LaCrO3 mixed oxide semiconductors have been investigated. The mixed oxides were obtained by mixing lanthanum nitrate, chromium nitrate and glycine in the 1:1:2 proportions respectively. Synthesized materials were characterized by X-ray diffraction (XRD), Infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). LaCrO3 was observed to be sensitive to acetone gas. Upon exposure to acetone gas, the barrier height of LaCrO3 intergranular regions decreases markedly due to the chemical transformation of LaCrO3 into well conducting electrons leading to a drastic decrease in resistance. The crucial gas response 200 ppm was found to acetone gas at 200 0C and no cross response was observed to other hazardous and polluting gases. The effects of microstructure on the gas response, selectivity, response and recovery of the sensor in the presence of acetone gas were studied and discussed.


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May 20, 2014