Preparation of nano-scale titania thick film and its oxygen sensitivity

Titania is a very important material for oxygen sensors. In this work, nano-scale titania films were prepared on alumina substrates by screen print. After being calcined at 800°C, all films became rutile. The oxygen sensing properties were studied and compared with the film made from micro-scale titania. The resistance of films were examined at various temperature and oxygen partial pressures. It was found that the nano-scale film demonstrated better properties than micro-scale film for use as an oxygen sensor. The oxygen sensitivity was obviously improved (13%) when the grain size was nano-scale. The improvement of oxygen sensitivity of nano-scale film may profit from its large surface area, which provides a high oxygen vacancy concentration.