Room-Temperature Benzene Sensing with Au-Doped ZnO Nanorods/Exfoliated WSe2 Nanosheets and Density Functional Theory Simulations

A gold-doped zinc oxide (Au-ZnO)/exfoliated tungsten diselenide (exfoliated WSe2) nanocomposite-based gas sensor toward benzene with high sensing properties was demonstrated. Epoxy resin was used as the matrix of the Au-ZnO/exfoliated WSe2 nanocomposite sensor. The straw-shaped Au-ZnO was synthesized by the hydrothermal method, and WSe2 nanosheets (NSs) were prepared via hydrothermal and liquid-phase exfoliation methods. The properties of Au-ZnO/exfoliated WSe2 nanoheterostructures constructed by self-assembly technology have been confirmed via a series of characterization methods. The benzene-sensing performances of sensors were tested at 25 °C. Compared with Au-ZnO, WSe2, and their composites, the Au-ZnO/exfoliated WSe2 sensor has a significant performance improvement, including a higher response and linear fit degree, better selectivity and repeatability, and faster detection rate. The significantly enhanced sensing properties of the Au-ZnO/exfoliated WSe2 sensor can be ascribed to the doping of Au nanoparticles, the increase in the specific surface area and adsorption sites of NSs after exfoliation, and the cooperative interface combination of the ZnO/WSe2 heterojunction. Furthermore, the sensitivity mechanism of the composite sensor to benzene was explored by density functional theory simulations.