介孔SnO2的结构表征及其湿敏性能

以十六烷基三甲基溴化铵、十二胺为模板剂, 采用双模板法及均相沉淀法, 分别制备了介孔结构的SnO2. BET测试结果表明, 双模板法制备的介孔SnO2平均孔径、孔容和比表面积分别为4.9 nm、0.213 m3·g-1和172.9 m2·g-1, 而均相沉淀法合成产物孔径分布的离散程度较大, 孔容和比表面积降至双模板法的66.0%和21.8%. 以叉指电极为工作电极集电体, 利用交流阻抗技术测定了所得SnO2的湿敏性能. 结果表明, 与均相沉淀法制备的SnO2 相比, 双模板法制得SnO2的双电层电荷传递阻抗、双电层电容及Warburg扩散系数随湿度变化的幅度更明显, 表明其具有较好的湿敏性能. 对介孔结构特征与湿敏性能相关性研究表明, 具有较大孔容和比表面的介孔SnO2可改善材料的感湿性能.

Structural Characteristics and Humidity Sensing of Mesoporous SnO2

Adouble-template (DT)method using hexadecyl trimethyl ammoniumbromide (CTAB) and dodecylamine (ODA) as templates and a homogeneous precipitation (HP) method were used to prepare mesoporous-SnO2. The BET characterization showed that the average diameter, total pore volume, and surface area of the DT-processed sample were 4.9 nm, 0.213 m3·g-1, and 172.9 m2·g-1, respectively. The sample prepared by the HP method had a considerably non-uniform distribution of pore size, while the total pore volume and surface area decreased to 66.0% and 21.8% of the corresponding value of the DT-processed material. Electrochemical impedance spectroscopy (EIS) was introduced to test the humidity sensing of the sensor made by the mesoporous-SnO2, using interdigitated electrodes as a working electrode. It was found that the charge transferring resistance, the electric double layer capacity, and the Warburg diffusive coefficient of the DT-processed sample generally exhibited a more significant change than that of the HP-processed sample, indicating that the DT-processed sample possessed a higher sensitivity to humidity. A closer look at the correlation between structural features and humidity sensing revealed that the humidity sensing of the sensor could be improved by obtaining the mesoporous SnO2 with higher pore volume and surface area.