Fully gravure-printed WO3/Pt-decorated rGO nanosheets composite film for detection of acetone

With the emergence of non-invasive disease diagnosis, the development of a specific volatile organic compounds (VOCs) gas sensors in exhaled breath is on-going. Described herein is a flexible and lightweight chemiresistor made of a thin film based on WO3/reduced graphene oxide (GO) nanosheets decorated with Pt nanoparticles, which were printed onto a flexible polyamide substrate by using gravure technique. In order to study the effect of graphene size on the performance of gas sensing, graphene with two sized such as large-sized reduced GO microsheets (GMs) and small-sized reduced GO nanosheets (GNs) were synthesized and used as modified materials incorporated into WO3-based system. The printed WO3/Pt-GNs sensor exhibits a good selectivity, a high response of 12.2 to 10 ppm acetone as well as a fast gas response/recovery time (14.1/16.8 s) at the operating temperature of 200 °C. The sensing performance is attributed to the exposed (002) facets of WO3 which were not wrapped into GNs, the massive p-n junction active sites at the WO3/GNs interface, as well as catalytic Pt nanoparticles. The printed WO3/Pt-GNs sensor is a promising candidate for selective, fast and sensitive detection of acetone at relatively low operating temperature.