Polyoxometalate-assisted in Situ Growth of ZnMoO4 on ZnO Nanofibers for the Selective Detection of Ppb-Level Acetone

One-dimensional (1D) semiconductor composite nanofibers (NFs) with large specific surface areas, high length-to-diameter ratios, and abundant interfacial active sites have received widespread attention. In this work, a rationally designed 1D composite NFs architecture for detecting acetone is synthesized via a two-step process based on electrospinning followed by a thermal oxidation method. Utilizing the polyoxometalate (POM) as a molecular platform with high negative charges to combine transition metal ions precursors, highly dispersed ZnMoO4 can be in situ grown on the ZnO. By adjusting the content of POM (H3PMo12O40, denoted as PMo12) in the precursor solution, we can obtain a series of ZnMoO4 decorated ZnO NFs (ZnMoO4-ZnO NFs). Compared with the pristine ZnO NFs, the ZnMoO4-ZnO NFs sensor exhibited excellent sensing characteristics over a wide range of acetone concentrations (50 ppb-50 ppm), such as high sensitivity , relatively low detection concentration, and high selectivity. The primary mechanism for the improved acetone gas sensing properties of the ZnMoO4-ZnO NFs could be ascribed to the available charge transfer and unique structure within ZnMoO4-ZnO NFs.