Gold functionalized MoO3 nano flakes for gas sensing applications

• Published in: Sensors and actuators. B, Chemical Vol. 269; pp. 331 - 339
• Main Authors: Munasinghe Arachchige, Hashitha M.M., Zappa, Dario, Poli, Nicola, Gunawardhana, Nanda, Comini, Elisabetta
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.09.2018
• Subjects: H2S detection; Metal oxide gas sensors; MoO3; Thermal evaporation; MoO3; Metal oxide gas sensors; H2S detection; Thermal evaporation
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2018.04.124

•Flakes-like (MoO3) successfully synthesized by evaporation-condensation method.•Au nanoparticles prevent the growth of thick layers of MoO3.•Au functionalization was performed on bare MoO3 nano flakes and enhance the gas sensing performance.•MoO3 NF nano flakes shows good sensitivity to Ethanol, Methanol, H2 and H2S and MoO3 nano flakes exhibit an excellent response to H2S. Molybdenum trioxide (MoO3) nano flakes (NF) with orthorhombic structure were synthesized by evaporation-condensation method using MoO3 powder as a raw material. Gold (Au) nanoparticles were used as a catalyst, preventing the growth of thick layers of MoO3. Furthermore, Au functionalization was performed by sputtering on pure MoO3 NF for a few seconds, decorating the flakes with Au nanoparticles. Chemical sensing performances were evaluated by introducing CO, NH3, Ethanol, NO2, Methanol, H2 and H2S gases in a syntetic air baseline with a relative humidity of 40% at 25 °C. MoO3 NF shows good sensitivity to Ethanol, Methanol, H2 and H2S gases. Owing to Au functionalization the devices exhibited an excellent response to H2S at an operating temperature of 400 °C: the response was 10 times higher than the pure MoO3, and the detection limit moved toward the ppb range.