Fabrication of PdNPs Doped TiO2 Nanotubes by Electroless Deposition as Hydrogen Sensor

Haidar Hameed Hamdan, Ghuson Hameed Mohammed

Titania nanotubes thin films have been prepared by electrochemical anodization of Ti foil at room temperature (~25ºC), in ethylene glycol base electrolyte with 0.5wt.% NH4F and 4wt% deionized water at 30V at time 3hr and then PdNPs-doped TiO2 nanotube arrays  at different deposition ratio were carried out by electroless deposition. These tubes are well aligned and organized into high-density uniform arrays. The average tube diameter, ranging in size from 61 to 74 nm, the length of the tube 2.13 µ, and ranging in size of wall thickness from 21 to 29 nm. A possible growth mechanism is presented. The TiO2 nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy (EDX.( The gas sensing was studied at the operating temperatures ranging from 25-350°C in different concentration hydrogen atmospheres ranging from (15, 30, 45, 60, 75ppm) H2. It was found that the TiO2 doped with Pd sensing film showed higher response of H2, with faster response time (within second) than pure TiO₂ sensing film. The response increased and the response time decreased with increasing of H2 concentration.