Reduced graphene oxide/hierarchical flower-like zinc oxide hybrid films for room temperature formaldehyde detection

We report a potential method to improve the room temperature formaldehyde (HCHO) gas-sensing properties of the layer-by-layer self-assembled reduced graphene oxide (rGO) film by introducing a special hierarchical flower-like zinc oxide (ZnO) structure. Hierarchical flower-like ZnO structures are developed by one step hydrothermal synthesis methods. Both rGO and rGO/ZnO sensitive films respond at once when exposed to HCHO at room temperature. The gas-sensing responses to 2-10 ppm formaldehyde are enhanced in rGO/ZnO hybrid films compared with pure rGO films. The enhanced formaldehyde gas-sensing responses are attributed to the more adsorption sites on the surface of the rGO/ZnO hybrid films and the reduced barrier height for the electron transfer during the gas sensing process. (C) 2015 Elsevier B.V. All rights reserved.