Dewyani Patil

Highly sensitive and fast responding CO sensor based on Co3O4 nanorods

Co(3)O(4) nanorods (diameters approximately 6-8 nm and lengths approximately 20-30 nm) were synthesized for the first time through a simple co-precipitation/digestion method by calcination of cobalt hydroxyl carbonate in air and their CO gas sensing properties were investigated. The Co(3)O(4) nanorods exhibited outstanding gas sensing characteristics such as, higher gas response (approximately 6.55-50 ppm CO gas at 250 degrees C), extremely rapid response (approximately 3-4s), fast recovery (approximately 5-6s), excellent repeatability, good selectivity and lower operating temperature (approximately 250 degrees C). Furthermore, the Co(3)O(4) nanorods are able to detect up to 5 ppm for CO with reasonable sensitivity (approximately 3.32) at an operating temperature 250 degrees C and they can be reliably used to monitor the concentration of CO over the range (5-50 ppm). The experimental results clearly demonstrate the potential of using the Co(3)O(4) nanorods as sensing material in the fabrication of CO sensors. Plausible CO sensing mechanism of the Co(3)O(4) nanorods is also discussed.

Investigation of poly(o-anisidine)-SnO2 nanocomposites for fabrication of low temperature operative liquefied petroleum gas sensor

Poly(o-anisidine)-tin oxide (POA-SnO2) nanocomposites has been investigated for the fabrication of low temperature operative (100 °C) liquefied petroleum gas (LPG) sensor. The POA-SnO2 nanocomposites have been synthesized through an in situ chemical polymerization of o-anisidine in presence of SnO2 nanoparticles. The POA-SnO2 nanocomposite shows better LPG sensing properties than that of pure POA. The nanocomposite with 50 wt. % SnO2 exhibits an excellent LPG sensing characteristics at the operating temperature of 100 °C such as higher relative gas response (∼23.47% to 3.4% of LPG), extremely rapid response (∼6 s), fast recovery (∼33 s), good reproducibility, and remarkable selectivity. The application of POA-SnO2 nanocomposites for fabrication of the LPG sensor was demonstrated.

Poly(o-anisidine) films on mild steel: electrochemical synthesis and biosensor application

Poly(o-anisidine) (POA) films were synthesized on mild steel from an aqueous oxalic acid solution by electrochemical polymerization of o-anisidine using cyclic voltammetry. These films were characterized by cyclic voltammetry, UV?visible absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The enzyme glucose oxidase (GOx) was entrapped into the POA film by a physical adsorption method. The resulting POA?GOx films were characterized by UV?visible absorption spectroscopy, FTIR and SEM. The amperometric response of the POA?GOx films was measured as a function of glucose concentration in phosphate buffer solution (pH 7.3). The POA?GOx films exhibited a fast amperometric response (1?5?s) and a linear response in the range of 2?20?mM glucose. The maximum current density and Michaelis?Menten constant of POA/GOx films were found to be ~406??A?cm?2 and 1.03?mM, respectively. The shelf stability, operational stability and thermal stability of these films were also investigated.