Abstract: Nanocrystalline ZnO-TiO₂ (~ 49-56 nm) was synthesized by hydrothermal method. Thick films were prepared by using synthesized nanocrystalline ZnO-TiO₂ (with molar ratio 9:1, 7:3 and 1:1) and their
gas sensing characteristics were investigated at different operating temperature. ZnO-TiO₂ thick film (with molar ratio 7:3) exhibited good response to H₂S as compared to other investigated compositions. Further, ZnO-TiO₂ thick films (with molar ratio 7:3) were modified by different concentrations of Fe₂O₃ and their H₂S
sensing characteristics were investigated. The 0.2M Fe₂O₃ modified ZnO-TiO₂ thick film (with molar ratio 7:3)
exhibited excellent H₂S sensing characteristics such as, high response (~ 314.67 at 40 ^oC), quick response
time (~ 8 s), less recovery time (~ 30 s), excellent repeatability and stability, good selectivity towards H₂S as compared to the other test gases like CO₂, LPG and NH₃ at 40 ^oC. The experimental results demonstrated that the Fe₂O₃ modified ZnO-TiO₂ Thick film is a very promising material to fulfills the practical requirement for the fabrication of H₂S sensors with good sensing characteristics.

Key words: Nanocrystalline, ZnO-TiO₂; Fe₂O₃, gas sensor, H₂S.

Cite: R. B. Pedhekar, F. C. Raghuwanshi, and V. D. Kapse, "Low Temperature H₂S Gas Sensor Based on Fe₂O₃ Modified ZnO-TiO₂ Thick Film," International Journal of Materials Science and Engineering, Vol. 3, No. 3, pp. 219-230, September 2015. doi: 10.17706/ijmse.2015.3.3.219-230