(Ti,Sn)O2 Nanopowders: Functional Properties for Gas Sensing

Great attention has been recently given to mixed metal oxides and solid solutions being promising candidates for gas sensing devices due the superior performances showed in comparison of their single-oxides counterparts [1]. This work focuses on the synthesis and the characterisation of TixSn1-xO2 (0.1 < x < 0.9, step 0.2) n-type semiconductor nanopowders and their sintered thick films. All materials were obtained via Symplectic Gel Coprecipitation (SGC) of stoichiometric Sn(4+) and Ti(4+) hydroalcoholic solutions and further calcination of the resulting xerogels. Calcination was performed at 550, 650, 850 or 1050°C, while the sintering of the film was carried out at 650, 750 or 850°C for 1h. Both type of thermal treatment were done under air flow conditions. The authors attempted to join advantages of SnO2, i.e. high sensitivity, and TiO2, i.e. gas response less affected by humidity than SnO2, and, possibly, to dump their disadvantages, i.e. poor selectivity for SnO2 , high resistivity and exaggerated grain growth for TiO2