Hybrid two-dimensional nanostructured hydrogen gas sensors

Two-dimensional (2D) nanostructured materials such as reduced graphene oxide (rGO) are highly promising for hydrogen (H2) sensing due to their narrow bandgap, number of active sites, and high surface area. Detection of hydrogen gas, a renewable and clean source of energy, in the atmosphere is of great importance in maintaining safety at all stages of hydrogen production, storage and use. In this work, a novel conductometric sensor has been developed based on hybrid 2D nanostructured rGO doped with Pd nanoparticles (Pd/rGO) to evaluate its sensing performance towards hydrogen with different concentrations (up to 1%). Various sensing parameters including sensitivity, response/recovery time, stability, and low detection limit have been investigated throughout the experiment. We also evaluate performance of the developed sensors at different operating temperatures (room temperature up to 120°C). Material properties of hybrid Pd/rGO film including surface morphologies, crystallinity, molecular vibration, functional groups, and oxidation states are sufficiently analysed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), profilometer, X-ray diffraction (XRD), and Raman spectroscopy. Furthermore, fundamental sensing mechanism governing the interactions between Pd/rGO and the hydrogen molecules are studied. It is anticipated that materials and techniques described in this work offers solutions to develop highly sensitive and portable hydrogen sensors with low power consumption and low fabrication and operation cost.