The effect of Ag loading on gas sensor properties of TiO2 nanorods

Abstract In this work, volatile organic compounds gas sensing properties of Ag loaded n-type TiO2 nanorods (NRs) were investigated. TiO2 NRs were grown by facile and cost-effective seed mediated hydrothermal process on alumina substrates. Ag loading on TiO2 NRs was performed by thermal evaporation technique with three evaporation durations (30, 45, and 90 s). Morphological and structural characterizations were carried out by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy (XPS). Sensor characteristics of pristine and Ag loaded TiO2 NRs were investigated for the detection of acetone, ethanol, hydrogen cyanide, and hydrogen sulfide gases. The gas sensing mechanism highlighting the enhanced sensitivity to acetone with Ag loading is discussed in correlation with detailed XPS studies. Gas sensing measurements show that the Ag loading substantially enhanced the sensitivity and selectivity against acetone. Also, the catalytic effect of Ag on TiO2 NRs surface reduced the operating temperature. Ag loaded TiO2 NRs sensor offered a sensor response for 65 ppb (particle per billion) acetone while there was not any observed response for pristine TiO2 NRs at optimal operating temperature (200˚C). Moreover, Ag loaded TiO2 NRs provided highly selective and sensitive acetone sensing performance at 100˚C.