A study of the physical properties and gas‐sensing performance of TiO₂ nanofilms: Automated nebulizer spray pyrolysis method (ANSP)

Abstract

Automated nebulizer-sprayed TiO 2 nanofilms were deposited on the glass substrate by using different temperature (300, 350, 400, 450, and 500 8C). The effect of temperature on the structural study by XRD and AFM reveals that the amorphous nature turns to stabilized anatase tetragonal phase with an enhancement of the preferred orientation (101), particle size, average roughness of the topographical view and thickness (238, 279, 304, 362, and 397 nm) of the coated films. The morphological study by the FESEM method shows a crack and a void free micro grain particle due to the effect of temperature.An optical study shows the transmittances of all the samples gradually decreased and the redshift of absorption edges with decreased bandgap (3.67-3.35 eV) value is observed by the influence of temperature. The n-type semiconducting nature of TiO 2 nanofilms shows the voltage drop across the sensor element on exposure to the reducing gas. Among the various gases (CH 4 O, C 3 H 8 O, NH 3 , C 3 H 6 O) the reducing gas C 2 H 6 O exhibits a better response for a 500 8C coating temperature at an optimal operating temperature of 300 8C with an 150 ppm gas concentration.

Morphological Evolution of TiO2 Nanoparticle Deposited on QCM Sensor at Various Calcination Temperature

“…The anatase phase is more suitable for gas sensor material because it has a larger band gap energy, wider surface area, and strong oxidizing power. It is also stable against photo-corrosion and has more efficient electron transport than other types of TiO2 [10,11]. TiO2 was chosen as the sensor material because it has a lot of oxygen vacancies, high surface area morphology, high reactivity, and selectivity for CO, which is present in many hydrocarbon gases [7].…”