Growth of porous ZnO single crystal hierarchical architectures with ultrahigh sensing performances to ethanol and acetone gases

Three-dimensional (3D) porous ZnO hierarchical architectures have been fabricated through annealing the zinc hydroxide carbonate precursor, which was obtained by a one-pot hydrothermal process with the assistance of carbon nano-fiber and cetyltrimethyl ammonlum bromide (CTAB). The ZnO hierarchical architectures are assembled from porous single crystal ZnO nanosheets. Experiment evidence reveals that carbon nano-fiber plays an important role in the formation of 3D hierarchical architectures. The growth mechanism of the 3D porous ZnO hierarchical architectures has been proposed based on control experiments. Gas sensing test results show that as prepared 3D porous ZnO hierarchical architectures exhibit superior sensing performance to ethanol and acetone. The sensor response to 100 ppm ethanol and acetone are 340 and 362 at the optimum operating temperature of 370 °C and 300 °C, respectively. The superior gas sensing performances are attributed to the unique 3D porous hierarchical architectures structure, the single crystal nature and the exposed polar crystal faces of ZnO nanosheet.