ZnO/activated carbon composites based gas sensor for flotation gases detection

At present, there is still a lack of monitoring of the gases produced in the flotation process in mines. As these gases with low concentration are mainly produced by flotation reagents, and the single metal oxide semiconductor based gas sensors are difficult to meet the requirements of use. Activated carbon is a porous material that is cheap and widely available, which can make enough flotation gases adsorb on the surface of gas sensing materials and change the sensor’s conductivity obviously. In this work, ZnO/activated carbon composites were synthesized by a facile one-pot hydrothermal method. The crystal structure, morphology, nanosize and chemical composition of the samples were investigated by XRD, FESEM, TEM, Raman spectroscopy, XPS and BET, respectively. The results showed that the gas sensing materials based on ZnO/activated carbon composites were able to detect the flotation gases such as butyl xanthate and terpineol. The gas sensor based on ZnO/activated carbon (10/1.5) composite reached the best response value of 28.90 at 75 ℃ for 1 ppm butyl xanthate gas, 8.67 at 100 ℃ for 0.5 ppm terpineol gas, as well as good reproducibility, which is potential for practical detection of flotation gases.