Facile two step synthesis of chemiresistive sensor based on γFe2O3—activated carbon composites for room temperature alcohol vapour detection.

Here in this research, Activated Carbon (AC)-γFe2O3 composite structures were prepared by pyrolysis of bamboo at 700–1000 °C temperatures. Characterization of the as-obtained samples by field-emission scanning electron microscopy, Raman spectroscopy, and X-ray diffraction analysis confirmed the formation of AC-γFe2O3 composite. The alcohol sensing performance of the composite structure at room temperature was investigated for different ethanol concentrations, which showed self-activated faster response/recovery, improved range of detection, and sensitivity. Ethanol sensing by the drop-casted AC-γFe2O3 films on a glass substrate was tested for various ethanol concentrations ranging from 50 to 500 ppm in water. The chemiresistive p-n-type heterojunctions formed between AC and γFe2O3 were attributed to the room temperature alcohol sensing performance of the material. AC-γFe2O3 prepared at 700 °C showed better sensitivity of 49% for 500 ppm ethanol concentration. The quickest response time was found to be 26 s for 100 ppm ethanol concentration with a recovery time of 15 s. [ABSTRACT FROM AUTHOR]