Characterization of three-dimensional reduced graphene oxide/copper oxide heterostructures for hydrogen sulfide gas sensing application

Three-dimensional reduced graphene oxide (3D-rGO) structures decorated with CuO particles (GCu) are synthesized through a simple and scalable method for detection of hydrogen sulfide (H₂S) gas. For characterization and investigation of porous structure various techniques were employed. Decorated 3D structures demonstrated higher sensitivity and selectivity in comparison to pure structure. Optimized structure for sensing was obtained through introducing different amounts of CuO. The GCu heterostructures containing 35 μmol of CuO powder demonstrated reproducible response of about 30% to the concentration of 10 ppm at room temperature, while complete recovery was obtained through heating to 150 °C. Sensing behaviour of the samples to H₂S gas was investigated at temperatures in the range of 25–150 °C and in different relative humidity levels from 3 to 80%. We discussed the sensing model based on the adsorption of H₂S molecules on the additives, and electron injection to the sample, resulting in the electrical resistance enhancement.