Effects of Surfactants on the Performance of CeO2 Humidity Sensor

Abstract EN

Nanosized CeO2 powders were synthesized via hydrothermal method with different types of surfactants (polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB), and sodium dodecylbenzenesulfonate (SDBS)).

X-ray diffraction, Raman spectroscopy, and transmission electron microscopy were utilized to characterize the phase structures and morphologies of the products.

The sample with CTAB as surfactant (CeO2-C) has the largest specific surface area and the smallest particle size among these three samples.

The humidity sensor fabricated by CeO2-C shows higher performance than those used CeO2-P and CeO2-S.

The impedance of the CeO2-C sensor decreases by about five orders of magnitude with relative humidity (RH) changing from 15.7 to 95%.

The response and recovery time are 7 and 7 s, respectively.

These results indicate that the performance of CeO2 humidity sensors can be improved effectively by the addition of cationic surfactant.