Novel Mixed Phase SnO2 Nanorods Assembled with SnO2 Nanocrystals for Enhancing Gas-Sensing Performance toward Isopropanol Gas
Novel Mixed Phase SnO2 Nanorods Assembled with SnO2 Nanocrystals for Enhancing Gas-Sensing Performance toward Isopropanol Gas
复制标题
与 SnO2 纳米晶体组装的新型混合相 SnO2 纳米棒可增强对异丙醇气体的气敏性能
DOI：
10.1021/jp501550w
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发表时间：
2014-05-08
影响因子：
3.7
通讯作者：
Djerdj, Igor
中科院分区：
文献类型：
--
作者：
Hu, Dan;Han, Bingqian;Djerdj, Igor
介绍了一种新型混合相(即四方相和正交相)共存的SnO2纳米棒的合成及其气敏性能。以SnCl2心点2H(2)0和PEG400为前驱体，采用化学沉淀法合成SnC2O4，经焙烧得到混合相SnO2纳米棒。得到的纳米棒呈由球形混合相SnO2纳米晶组成的多晶，具有较高的比表面积。结果表明，焙烧温度是决定正交相含量的关键参数。将合成的化合物作为间接加热结构传感器的敏感材料，测试了它们对异丙醇、丙酮、酒精和甲醛等挥发性有机化合物(VOCs)的检测能力。气敏测试表明，这种混合相SnO2纳米棒具有很高的气敏应用前景，因为正交相的存在显著提高了异丙醇的气敏响应(在1000ppm异丙醇时S=61.5%，响应时间和恢复时间分别为4和10 S)。在255℃的最佳操作温度下，所制备的具有最高正交相含量的两相SnO2纳米棒对异丙醇气体具有良好的气体响应、选择性和稳定性。灵敏度的提高归因于平均半径小于SnO2的德拜屏蔽长度7 nm的小的正交相SnO2晶体的存在。
The synthesis and the gas sensing properties of novel mixed phase (i.e., tetragonal and orthorhombic phase) coexistence SnO2 nanorods are presented. The mixed phases SnO2 nanorods were obtained by calcinations of SnC2O4 synthesized with a chemical precipitation method using SnCl2 center dot 2H(2)0 and PEG 400 as precursors. The resulting nanorods appear as polycrystalline composed of spherical mixed phases SnO2 nanocrystals and have a high surface area. It was observed that the calcination temperature was the key parameter determining the content of the orthorhombic phase. The as-synthesized compounds were used as sensing materials of the sensors of indirect heating structure and tested for their ability to detect volatile organic compounds (VOCs), such as isopropanol, acetone, alcohol, and formaldehyde. Gas sensing tests showed that these mixed phases SnO2 nanorods are highly promising for gas sensor applications, as the gas response for isopropanol was significantly enhanced by the presence of orthorhombic phase (S = 61.5 at 1000 ppm isopropanol and response time and recovery time of 4 and 10 s). The as-prepared two phases SnO2 nanorods with the highest content of the orthorhombic phase exhibit excellent gas response, selectivity, and stability toward isopropanol gas at the optimized operating temperature of 255 degrees C. The enhancement in sensitivity is attributed to the presence of small orthorhombic SnO2 crystals with average radius shorther than the Debye screening length of 7 nm for SnO2.