Hydrogen sensing properties of Pd loaded TiO$_2$ nanorods


Abstract: The hydrogen sensing performance of palladium (Pd) catalyst loaded TiO$_2$ nanorods based sensors were investigated. TiO$_2$ nanorods were grown on Al$_2$O$_3$ substrate by a facile hydrothermal process. TiO$_2$ nanorods (NRs) were functionalized with Pd metal by RF magnetron sputtering. Samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques for structural and morphological analysis. Sensor measurements toward H$_2$ and some volatile organic compounds (VOCs) such as acetone, ethanol, xylene and toluene were performed by varying gas concentrations at different temperatures. The sensors were found to exhibit excellent sensitivities towards different hydrogen concentrations ranging from 25 to 1000 ppm in air. The effects of different operating temperatures on the sensing performance of the devices were studied in the range of 100-200$^{\circ}$C. It was observed that the 2 nm Pd?loaded and 4 nm Pd-loaded sensors were approximately 12 and 44 times more sensitive than the pristine TiO$_2$ nanorods sensor, respectively. The effect of temperature dependence on sensor response and the influence of the metal loading for hydrogen sensing are presented and discussed.

Keywords: Chemiresitive gas sensor, H$_2$ sensor, TiO$_2$ nanorods, Pd loading, surface functionalization, surface modification

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