Pt-Ion Irradiated MoO3: Synthesis and its Applicability in Hydrogen Sensor Devices
Paulino Cordero, Leandro Guillermo
Fonseca, Luis (Consejero)
Gas sensors based on semiconducting metal oxides are commonly used in the markets of automotive, aerospace and logistic applications due to their stability and favorable response while monitoring toxic and combustible gases, being the main drawback their operating temperature. In particular, semiconducting molybdenum oxide (MoO3) has been proved to be highly sensitive to NO2, NH3, CO, H2, among others, in the temperature range between 300 °C and 450 °C. The goal of this work is to reduce the operating temperature of a MoO3 based sensor prototype by developing an oxide-metal composite with catalytic properties. Orthorhombic MoO3 microbelts were synthesized by Chemical Vapor Deposition in two stages using MoCl5 precursor powders. The as-synthesized material was liquid exfoliated to reduce sample’s thickness to the nanoscale and, at the same time, its electrical resistance. Finally, platinum ions were added by 9 keV Pt-ion irradiation to serve as catalyst during hydrogen gas exposure. XRD was used to confirm successful synthesis of the material; SEM to assess the thickness reduction and to retrieve EDS spectra to confirm successful Pt-ion deposition over liquid exfoliated MoO3. Pt-MoO3 samples were integrated to gold interdigitated electrodes and later heated at 300°C for 15 minutes to ensure connectivity between MoO3 and the electrodes, with the goal of performing gas sensing tests on the device. The sensor showed response to H2 gas at 100°C, 50°C and room temperature at different concentrations.