Sensing Enhancement of Gold Nanoparticles Doped-TiO₂ Thin Films as H₂S Gas Sensor

Abstract

Titanium dioxide and gold nanoparticles were synthesized using an environmentally friendly method to deposit undoped and Au-doped TiO2 thin films on silicon and glass substrates via the spray pyrolysis technique. The effect of the Au nanoparticles concentrations on structural, morphological, and hydrogen sulfide (H2S) gas sensing characteristics of TiO2 thin films were investigated. An X-ray diffraction pattern confirmed the polycrystalline structure of the films deposited on glass and Si substrates with a dominant rutile phase and the formation of additional mixed-phases of Ti-Au bonding. According to a Field Emission-Scanning Electron Microscopy investigation, the cluster size ranged from 20 to 180 nm depending on the concentration of AuNPs. The sensing response of the prepared films was tested against H2S at different operating temperatures. The effect of growing a mixture of titanium-gold phases as a suitable catalyst for hydrogen sulfide sensitivity is also discussed.