A series of polyaniline and sodium dodecanesulfonate co-intercalated layered double hydroxides (LDH/PANI/SDS) have been obtained by a coprecipitation method. The composites have been named LiAl-LDH/PANI/SDS, MgAl-LDH/PANI/SDS, and NiAl-LDH/PANI/SDS according to the composition of the LDH nanosheets. The structure and chemical composition of the composites have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetry and differential thermal analysis. It has been observed that SDS serves as both the interlayer anion and the template for the formation of LDH sheets, which induces the co-intercalation of PANI. All the composites have been incorporated into humidity sensors and humidity sensing experiments have been conducted. It has been found that the humidity sensors based on LDH/PANI/SDS demonstrate good humidity properties with good linearity, low hysteresis, good stability and rapid response compared with PANI alone. The sensing mechanism of the composites has also been discussed.

•One source precursor was applied for the preparation of ZnO/ZnFe2O4 composite.•Sensing to triethylamine vapor was enhanced by light irradiation.•Light irradiation lowered the working temperature of ZnO/ZnFe2O4 gas sensor.Light irradiation enhanced ZnO/ZnFe2O4 sensors for triethylamine gas detections have been reported in this paper. ZnO/ZnFe2O4 composites with a hexagonal nanostructure were synthesized by calcination of Zn, Fe layered double hydroxides (Zn2Fe-LDH) at certain temperatures. Focusing on the general problem that the metal oxide gas sensors for triethylamine detection often have high working temperatures around 200 °C, the assistance approach of light irradiation has been conducted in our work. Under the light irradiation, the gas sensing measurement indicates that the sample calcined at 600 °C shows considerable response to triethylamine at the working temperature of 80 °C. For comparison, the introduction of light irradiation has lowered the working temperature markedly, which might have potential to monitor TEA in industrial production in the future.