Low-temperature growth of ZnO nanoparticles: photocatalyst and acetone sensor.
ABSTRACT Well-crystalline ZnO nanoparticles (NPs) were synthesized in large-quantity via simple hydrothermal process using the aqueous mixtures of zinc chloride and ammonium hydroxide. The detailed structural properties were examined using X-ray diffraction pattern (XRD) and field emission scanning electron microscope (FESEM) which revealed that the synthesized NPs are well-crystalline and possessing wurtzite hexagonal phase. The NPs are almost spherical shape with the average diameters of ∼ 50 ± 10 nm. The quality and composition of the synthesized NPs were obtained using Fourier transform infrared (FTIR) and electron dispersed spectroscopy (EDS) which confirmed that the obtained NPs are pure ZnO and made with almost 1:1 stoichiometry of zinc and oxygen, respectively. The optical properties of ZnO NPs were investigated by UV-vis absorption spectroscopy. Synthesized ZnO NPs were extensively applied as a photocatalyst for the degradation of acridine orange (AO) and as a chemi-sensor for the electrochemical sensing of acetone in liquid phase. Almost complete degradation of AO has taken place after 80 min of irradiation time. The fabricated acetone sensor based on ZnO NPs exhibits good sensitivity (∼ 0.14065 μA cm(-2) mM(-1)) with lower detection limit (0.068 ± 0.01 mM) in short response time (10s).
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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.Sensors & Transducers Journal (S&T e-Digest) (ISSN 1726-5479). 02/2012; 137(2-(ISSN 1726-5479)):165-175.
Article: Citrate Assisted Hydrothermal Synthesis of Single Crystalline ZnO Nanoparticles for Gas Sensor ApplicationSensors and Actuators B Chemical 01/2012; · 3.90 Impact Factor