Doped TiO2-Nanotubular Sensor Electrodes for Gas Sensing Applications

Abstract

Relying on its unique properties, titanium dioxide is employed in a versatility of applications, gas sensing being one of them. Low temperature synthesis of doped TiO2-coatings and their nano-structuring enhance these properties. It is reported that the use of one-dimensional (1-D) nanostructures instead of nano-crystalline films yields more than 2-fold increase in efficiency by improving the sensing properties. Nano-tubular sensing electrodes improve sensing performance due to high surface to volume ratio and thus enabling strong interaction between the surrounding gas and the sensing material. This work reports the synthesis of coatings having TiO2-nanotubes by AAO-templated and non-templated anodic oxidation method. Using these coatings gas sensor devices was fabricated and their sensing properties were analyzed towards reducing and oxidizing gases. Long-term stability of the nano-structures was investigated to determine the life-time of sensors. Additionally trivalent additive doped TiO2 nanotubes were synthesized by AAO-templated sol-gel method and phase sequences with composition and temperature were analysed. Sensor properties obtained with various compositions and synthesis methods were compared.