Synthesis of Ag quantum dots sensitized WO3 nanosheets and their enhanced acetone sensing properties

Ag quantum dots (QDs) sensitized WO3 nanosheets have been synthesized by a facile two-step wet-chemical method and the subsequent annealing treatment. The structures, morphologies and surface compositions of the materials were characterized by XRD, FESEM, FETEM, and XPS techniques. FETEM results indicating that the monodispersed Ag QDs with an average size of 4.5 nm are uniformly coated on the surface of WO3 nanosheets. Gas sensing test results show that the gas sensing performance, including sensitivity, response/recovery rate, and selectivity of the Ag QDs sensitized WO3 nanosheet sensor were significantly improved as compared to the pristine WO3 nanosheet sensor. Analysis suggests that the enhanced gas sensing performance can be attributed to the electron sensitization and chemical sensitization of Ag QDs.