新型室温硫化氢纳米传感器的制备及性能

Fabrication and Characteristics Investigation of a Novel Nanosensor for Sulfuretted Hydrogen Operating at Room Temperature

采用溶胶-凝胶法在叉指金电极表面制备纳米二氧化钛（TiO2）多孔薄膜,并用浓度为2.5×104 mol/ L的花青素对其进行敏化,制备了一种能在室温条件下检测硫化氢（H2 S）的高灵敏度传感器.从材料的光谱特性、微观结构和传感器的灵敏度等方面对该传感器的性能进行了评价,并讨论了传感器的响应机理以及温度和湿度对灵敏度的影响.结果表明,材料表面的可见吸收光谱比花青素红移了约50 nm,吸收能力有所提高；纳米 TiO2颗粒呈层状堆积排列,颗粒之间具有较多缝隙,比表面积大.在室温下,该气体传感器对浓度为5~50 mL/ m3的 H2 S 具有良好的敏感特性,传感器灵敏度与 H2 S 浓度呈线性相关,相关系数为0.939,响应时间为50~70 s,恢复时间为160~180 s.计算和测试结果表明,环境湿度约为50%时传感器的灵敏度最佳；在10~50℃范围内,温度与传感器的灵敏度存在负相关性.该方法为简单、经济制备室温条件下工作的气体传感器提供了新思路和新方法.

A sulfuretted hydrogen sensor operating at room temperature based on pigment-sensitized TiO2 films was fabricated. TiO2 was prepared by sol-gel method and deposited on glass slides containing gold electrodes. The film was then immersed in a 2. 5 ×10-4 mol/ L ethanol solution of cyanidin to absorb the pigment. For characterization of texture, UV-Vis diffuse reflectance spectra, field emission scanning electron microscopy, sulfuretted hydrogen adsorption-desorption measurements and temperature, humidity measurements were adop-ted. The results demonstrate that the sol-gel layers show a high porosity, a slightly more compact material close to the substrate. The cyanidin-sensitized TiO2 nanosheets exhibit a clear red shift（50 nm） compared with cyanidin. The hybrid organic-inorganic formed film can detect sulfuretted hydrogen reversibly at room tempera-ture. The sensitivity of the films increased almost linearly with increasing the concentrations of sulfuretted hy-drogen（R2 =0. 939）. The response time to increasing concentrations of the sulfuretted hydrogen is about 50 ~70 s, and the corresponding values for decreasing concentrations 160 ~ 180 s. At low humidity, sulfuretted hy-drogen could be ionized by the cyanidin on the TiO2 film and thereby decrease in the proton concentration at the surface. The resistance response to sulfuretted hydrogen of the sensors was nearly independent on tempera-ture from 10 ℃ to 50 ℃. This preliminary work proposes simpler and cheaper processes to fabricate gas sensor for room temperature applications.