Nanostructured TiO2-based mixed metal oxides prepared using microemulsions for carbon monoxide detection

Abstract

Nanostructured powders of Nb-doped TiO2 (TN) and SnO2 mixed with Nb-doped TiO2 in two different atomic ratios-10 to 1 (TSN 101) and 1 to 1 (TSN 11)-were synthesized using the reverse micelle microemulsion of a nonionic surfactant (brine solution/1-hexanol/Triton X-100/cyclohexane). The powders were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Thick films were fabricated for gas sensors and characterized by XRD analysis and field emission scanning electron microscopy (FE-SEM). The effects of the film morphology and firing temperature in the range 650-850 °C on CO sensitivity were studied. The best gas response, expressed as the ratio between the resistance in air and the resistance under gas exposure (R air/R gas), was measured for TSN 11 at 11 for 1,000 ppm CO exposure. All types of sensors showed good thermal stability. The electrochemical impedance spectroscopy (EIS) measurements were performed in different gas atmospheres (air, O2, CO and NO 2) to better understand the electrical properties of the nanostructured mixed metal oxides. © 2007 Springer Science+Business Media, LLC

Synthesis of CuO@NiO core-shell nanoparticles by homogeneous precipitation method

“…For the synthesis of mixed metal oxide nanoparticles, different methods such as homogenous precipitation [15][16][17], coprecipitation [18,19], impregnation [20], sol-gel [21,22], sonochemical [23], micro-emulsion [24], hydrothermal [25], thermal decomposition [26] and chemical vapor deposition [27] have been employed. Among the reported preparation methods, solution based ones possess some advantages; they lead to materials with fine particle size, high purity and good homogeneity.…”