Synthesis, characterization and sensing application of novel semiconductor oxides

Mesoporous SnO2 with high surface areas were synthesized using a cationic surfactant (N-cetyl-N,N,N-trimethylammonium bromide) as a synthetic template. Acidity of the starting synthesis slurry was used as one of the controlling parameters for the synthesis. After the SnO2 was synthesized at pH 7.15, it was calcined at 723 K for 10 h in air. It had a BET surface area of 156.8 m(2) g(-1) with a pore diameter of 38.4 Angstrom. Infrared spectroscopy (FTIR) and thermal analysis techniques (thermogravimetry and differential thermal analysis) showed that the surfactant was incorporated in the mesopores of SnO2 and calcination in air at 673-723 K was needed to remove the surfactant completely from the mesopores. The effects of SnO2 surface area on its gas sensing properties were also investigated. It was observed that SnO, with higher surface areas had much higher sensitivities to hydrogen at 573 K. (C) 1998 Elsevier Science B.V.