Efficient Room Temperature Hydrogen Gas Sensor Using ZnO Nanoparticles-Reduced Graphene Oxide Nanohybrid

In this work, a highly sensitive room-temperature hydrogen gas-sensor based on reduced graphene oxide (rGO) and zinc oxide nanoparticles (ZnO NPs) nanohybrid structure is reported. ZnO NPs were grown by chemical deposition method while the rGO layer was produced by the electrochemical exfoliation using tetramethyle ammonium hydroxide (TMAH) as organic solvent and then drop-casted on the ZnO NPs layer.The detailed morphological [Field Emission Scanning Electron Microscope (FESEM)] and structural [Raman and X-ray Photoelectron Spectroscopy (XPS)] analysis were carried out to compare different properties of pristine ZnO NPs and rGO-ZnO NPs hybrid structure.The rGO-ZnO NPs nanohybrid sensor with a Pd-Ag (70 %) catalytic contact was tested for five different hydrogen concentrations (e.g. 100, 500, 1000, 5000 and 10000 ppm) in synthetic air at room temperature (RT). The sensor showed 484.1 % response magnitude with 21.04 s and 47.09 s response and recovery time at 100 ppm H2. A comparative study explaining the role of rGO-ZnO heterojunction co-relating the experimental findings has also been presented. The physics behind this room temperature sensing has been discussed thoroughly with supportive band diagram.