ZnO-SnO_2纳米复合氧化物的制备、表征及其气敏性质的研究(英文)

Preparation, Characterization and Gas Sensing Properties of ZnO-SnO_2 Nanocomposites

本文用可控湿化学共沉淀法研制了ZnO-SnO2纳米晶体复合气敏材料并考察其对有毒气体CO和NO2的气敏性质。用TEM、BET和XRD等方法表征了纳米复合物的粒度、形貌、比表面、热稳定性和相稳定性。研究了制备的可控参数,如金属阳离子总浓度、沉淀pH值和老化时间等对复合物气敏性质的影响。研究结果表明,该纳米复合氧化物具有化学均一性,高度热稳定和相稳定性,对CO和NO2具有高的灵敏度和选择性,其气敏性质依赖于复合物组成、焙烧温度和操作温度。通过2wt%金属Cd的掺杂和10wt%Al2O3氧化物的表面包覆大大提高了气体的灵敏度和选择性。用程序升温吸脱附研究了纳米复合物表面对气体的吸脱附性能,并探讨了气敏机理。

Novel gas sensing materials of ZnO-SnO2 nanocomposites were developed using controlled coprecipitation and their sensitivity and selectivity were tested by the detection of environmentally toxic gases. Through manipulating the reaction conditions, such as the Sn/Zn cation ratio, metal salt total concentration, precipitation pH and aging time etc., the nanocrystalline composites with chemical homogeneity and superior thermal stability were successfully prepared and the optimized synthesis parameters have been established. The results showed that these nanocomposites exhibited high sensitivity and selectivity for the detection of CO and NO2, and the sensitivity was dependent on the composition of nanocomposites, calcination and operating temperatures. The sensing performance was greatly enhanced by the introduction of a small amount of Cd or Al2O3 oxide coatings. The gas sensing mechanism of the nanocomposites was also discussed by temperature-programmed desorption (TPD) studies.