Synthesis of three-dimensional flower-like hierarchical ZnO nanostructure and its enhanced acetone gas sensing properties

A three-dimensional (3D) flower-like hierarchical ZnO nanostructure was successfully synthesized via a facile and efficient hydrothermal method. The sample was characterized by XRD, FESEM, Raman, UV-vis DRS and Photoluminescence (PL) techniques. The XRD pattern revealed that the sample was well-crystallized in a hexagonal wurtzite structure. FESEM images showed that the as-prepared ZnO exhibited a nanosheet-assembled hierarchical flower-like ZnO nanostructure, which was self-assembled by thin and uniform nanosheets with a thickness of approximately 30 nm. Raman spectra exhibited that the sample kept the crystal structure of the bulk ZnO and possessed more surface defects. UVevis spectra showed that a significant blue-shift in the absorption edge for the as-prepared ZnO as compared to the commercial ZnO. PL spectra indicated that the concentration of surface oxygen vacancies in the as-prepared ZnO was much higher than that of the commercial ZnO. Furthermore, the nanosheet-assembled flower-like ZnO nanostructure exhibited excellent gas sensing properties towards acetone, indicating that the as-prepared ZnO architecture is a promising material for gas sensors. (C) 2015 Elsevier B.V. All rights reserved.