Amorphous Carbon-Loaded WO3 Nanosheet Arrays for ppb-Level NO2 Sensing with Improved Anti-Humidity Property

Metal-oxide-based gas sensors have attracted considerable interest due to their low cost, high sensitivity, quick response, and ease of miniaturization and integration. Unfortunately, metal oxides are susceptible to the interference of moisture, which brings about hydroxyl poisoning of the sensing layer and decrement in baseline resistance and sensor performance. In this study, WO₃ films were modified with a porous amorphous carbon layer. The as-loaded amorphous carbon layer improves simultaneously the adsorption capacity of WO₃ and hydrophobicity of the surface, which endows the composite films with not only surpassing NO₂ sensitivity at the parts per billion level but also enhanced immunity to humidity. The incorporation of amorphous carbon with metal oxides is expected to be a general route for the fabrication of high performance, antihumidity gas sensors.