Preparation Of SnO₂ Nanomaterials And Their Gas-Sensing Performance

As an n-type semiconductor oxide with a wide band gap(Eg = 3.6 e V), SnO2 is well-known for its potential applications in transparent conductive electrodes and transistors, Li-ion batteries, dye-sensitized solar cells and ultrasens itive gas sensors. SnO2 nanomaterial is attracting a great deal of attention due to its unique properties and novel applications. Therefore, the development of high sensitivity, fast response, low detection limit, high selectivity gas sensors are urgent issue to be solved.The subject clue of this thesis is the synthes is of porous SnO2 nanomaterials. The mesoporous SnO2 was synthesized by soft-templating method and hard-templating method, respectively. And the their gas-sensing properties have also been studied. Moreover, Zn2 Sn O4 nanomaterials have been successfully fabricated by using a simple hydrothermal route.The main results are listed as following:1. The mesoporous SnO2 nanomaterials were synthes ized by softtemplating method, using stannic chloride(Sn Cl4?5H2O) as the stannous source, hexadecyl trimethyl ammonium bromide(CTAB) as structuredirecting agent. The effect of different calc ination temperature on the morphology and gas sensitive performance of SnO2 was examined. The results show that the synthesized mesoporous SnO2 materials owned good crystallinity when calc ined at 400℃. Comparing with SnO2 nanoparticles, the mesoporous SnO2 fabricated at 400℃ presented better response, recovery performance, and gas sensitivity. Furthermore, when gas sensitive test temperature was 200℃, the mesoporous SnO2 showed better sensitivity for ethanol selectively than CO, H2, gasoline and acetone.2. The mesoporous SnO2 nanopartic les were synthes ized by hardtemplating method, using mesoporous silica(MCM-41) as the hard template, stannous chloride(Sn Cl2?2H2O) as stannous source. The synthesized SnO2 nanopartic les showed excellent sensitivity to ethanol selectively when the test temperature is 160℃. Moreover, the sensitivity of it increased with the increasement of ethanol, and the sensitive stability of it is preferable.3. The optimum synthes is method of Zn2 Sn O4 nanomaterials has been obtained through investigating the tin sources, the reaction temperature, alkali sources, p H values, the kinds of surface active agents, and so on. The results show that when stannic chloride(Sn Cl4?5H2O) as the tin source reacted with zinc acetate(Zn(Ac)2?2H2O), which required high reaction temperature. The Zn2 Sn O4 with pure phase was fabricated when the reaction temperature attained 200℃. When sodium stannate(Na2Sn O3?3H2O) as the stannous source reacted with Zn(Ac)2?2H2O, which required relatively low reaction temperature. When the reaction temperature attained 160℃, the Zn2 Sn O4 with pure phase was fabricated, which owns more uniform morphology than the previous one.