Highly conductive titanium oxide nanotubes chemical sensors

Nb-TiO2 nanotubes arrays have been prepared by anodisation of Nb-Ti metallic films. After the annealing treatment the nanotubes are crystallized in the anatase phase. Conductance increased of several orders of magnitude thanks to the introduction of Nb. We have prepared conductometric sensors and evaluated their sensing properties towards different gases. Functional measurements demonstrated very good sensing performances towards ethanol, acetone and carbon monoxide. The gas sensing performances has been tested as a function of the dimensions of the nanotubes showing an improvement in chemical sensing as the internal diameter of the tubes get smaller.