Hydrogen Sensing with Ni-Doped TiO(2) Nanotubes

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, Ni-doped TiO(2) nanotubes were fabricated through anodic oxidation of NiTi alloy and further annealing treatment. The hydrogen sensing properties of the nanotube sensor were investigated. It was found that the Ni-doped TiO(2) nanotubes were sensitive to an atmosphere of 1,000 ppm hydrogen, showing a good response at both room temperature and elevated temperatures. A First-Principle simulation revealed that, in comparison with pure anatase TiO(2) oxide, Ni doping in the TiO(2) oxide could result in a decreased bandgap. When the oxide sensor adsorbed a certain amount of hydrogen the bandgap increased and the acceptor impurity levels was generated, which resulted in a change of the sensor resistance.