Synthesis of SrTiO₃ Nanopowder by Sol-Gel-Hydrothemal Method for Gas Sensing Application

Strontium titanate (SrTiO₃) nanopowder has been synthesized through a sol-gel-hydrothermal method. The X-ray diffraction studies of SrTiO₃ nanopowder have shown that the as-prepared powder was single phase, crystalline, and has a cubic perovskite structure (ABO₃) with a lattice constant a = 3.903 Å. The particle size calculated from FWHM was ∼22 nm. SrTiO₃ nanopowder was examined using thermo gravimetric analysis; differential thermal analysis and UV-visible absorption spectroscopy. The transmission electron microscopic investigations have shown that the particle size of the as-prepared powder has a mean size of 34 nm. Then highly sensitive and selective sensors to H₂S based on glass substrate were fabricated successfully by screen-printing technique. Sensitivity, selectivity, response time, and recovery time of the sensors were systematically investigated as a function of operating temperature, using H₂S, CO, CO₂, H₂, Cl₂, LPG, C₂H₅OH, O₂, NH₃ and NO₂ as test gases. The sensitivity was found to lie below and around the ppm level for H₂S gas at 150 °C.