Extreme Changes in the Electrical Resistance of Titania Nanotubes with Hydrogen Exposure

Extremely sensitive, drift‐free, and robust hydrogen sensors based on titania nanotube arrays (see Figure) are reported. Very large changes in the electrical conductivity of the nanotubes upon exposure to hydrogen gas have been measured, over one order of magnitude greater than the previous record. Dependence of the electrical conductivity on both temperature and nanotube pore size is found.