p-Type hydrogen sensing with Al- and V-doped TiO(2) nanostructures

Doping with other elements is one of the efficient ways to modify the physical and chemical properties of TiO(2) nanomaterials. In the present work, anatase TiO(2) nanofilms doped with Al and V elements were fabricated through anodic oxidation of Ti6Al4V alloy and further annealing treatment. Hydrogen sensing behavior of the crystallized Ti-Al-V-O nanofilms at various working temperatures was investigated through exposure to 1,000 ppm H(2). Different from n-type hydrogen sensing characteristics of undoped TiO(2) nanotubes, the Al- and V-doped nanofilms presented a p-type hydrogen sensing behavior by showing increased resistance upon exposure to the hydrogen-containing atmosphere. The Ti-Al-V-O nanofilm annealed at 450°C was mainly composed of anatase phase, which was sensitive to hydrogen-containing atmosphere only at elevated temperatures. Annealing of the Ti-Al-V-O nanofilm at 550°C could increase the content of anatase phase in the oxide nanofilm and thus resulted in a good sensitivity and resistance recovery at both room temperature and elevated temperatures. The TiO(2) nanofilms doped with Al and V elements shows great potential for use as a robust semiconducting hydrogen sensor.