Investigation the AMOST effect on the sensitivity of CeO2/Ni-Al layered double hydroxide composite based sensors

Layered double hydroxides (LDHs) suffer from aggregation and agglomeration despite their unique layered structure, high porosity, and large specific surface area. This feature has limited the use of LDH structures in the field of gas sensors. In order to solve this limitation in this study, (CeO2)(x)/Ni-Al LDH and (CeO2)(x)/Ni-Al-AMO LDH composites (AMO: Aqueous Miscible Organic) were prepared based on ceria nanorods in three different size during hydrothermal and co-precipitation processes. The characteristics of the composites have been investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Mott-Schottky (MS). The gas sensing performance of the sensors was investigated at room temperature (25 degrees C), relative humidity (40 % RH) and in the range of 25-300 ppm for three VOCs (including methanol, ethanol and acetone). According to the obtained results, AMO solution increases the sensitivity and decreases the response/recovery times due to the provision of surface active sites. Thus, the proposed approach makes it possible to prepare a sensor with improved performance. Finally, the response mechanism was discussed based on the heterojunction theory.