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采用溶胶凝胶法制备了纯TiO2和掺杂质量分数为5%,7%和9%CuO的TiO2纳米粉体,并对样品进行了不同温度(500,700和900℃)的退火处理。通过涂敷法制备成气敏元件,利用XRD和SEM对样品的结构和表面形貌进行了表征,并利用气敏测试系统检测其气敏特性。研究了CuO掺杂质量分数和退火温度对TiO2厚膜气敏性能的影响,进一步讨论了TiO2厚膜的气敏机理。结果表明:CuO的掺杂有效抑制了TiO2晶粒的生长,增加了对光子的利用率,降低了工作温度,提高了气敏特性。700℃退火后,质量分数为7%的CuO掺杂TiO2样品的结晶尺寸达到14.5 nm,气敏元件表现出对丙酮蒸汽单一的选择性,灵敏度为3 567,响应和恢复时间均为2 s。
Pure TiO2 and doped TiO2 nano-powders doped with 5%, 7% and 9% CuO were prepared by sol-gel method. The samples were annealed at different temperatures (500, 700 and 900 ℃). The gas sensing element was prepared by coating method. The structure and surface morphology of the sample were characterized by XRD and SEM. The gas sensing properties were also measured by gas sensing system. The effects of CuO doping mass fraction and annealing temperature on the gas sensing properties of TiO2 thick films were investigated. The gas sensing mechanism of TiO2 thick films was also discussed. The results show that CuO doping effectively inhibits the growth of TiO2 grains, increases the utilization of photons, decreases the working temperature and improves the gas sensing properties. After annealing at 700 ℃, the crystal size of CuO-doped TiO2 with 7% mass fraction reached 14.5 nm. The gas sensor showed a single selectivity to acetone vapor with a sensitivity of 3 567 and a response and recovery time of 2 s.