Abstract: 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.

Key words: Mesoporous tin oxide, Double-template method, Homogeneous precipitation method,
Electrochemical impedance spectroscopy