Room temperature hydrogen sensitivities of a new type hydrogen sensor with Pd nanoclusters/TiO₂ nanotubes composite structure

A new type Pd nanoclusters/TiO₂ nanotubes composite structure hydrogen sensor was made of Pd nanoclusters, TiO₂ nanotubes and Ag as the electrodes. Microstructure of the sensor was characterized by scanning electron microscope (SEM), and it showed that the Pd nanoclusters were deposited on the top of TiO₂ nanotubes in isolation. Crystalline of composite analyzing was characterized by X-ray diffraction (XRD), and it showed that amorphous TiO₂ has been converted into anatase and rutile completely after annealing at 500℃. The hydrogen sensing characteristic was tested in series of hydrogen concentration at room temperature, and it revealed that the sensor has excellent response performance. The response time and sensitivity of the sensor was 3.8 s and 92.05%, respectively, at 8000 ppm hydrogen concentration. It was demonstrated that the fast response and high sensitivity hydrogen sensor can be made by using the Pd nanoclusters/TiO₂ nanotubes composite structure.