Toluene and ethanol sensing performances of pristine and PdO-decorated flower-like ZnO structures

The flower-like pristine (ZnO) and PdO-decorated ZnO (PdO-ZnO) materials with hierarchical structure were synthesized by a surfactant-free hydrothermal route and subsequent heat treatment. This method requires high concentrations of a zinc precursor (0.1 M) and introduction of an amount of PdO nanoparticles into the reaction system. The flower-like ZnO nanostructures comprises many aggregative rods with the diameter of about 200 nm. Having fabricated gas sensors based on the pristine and PdO-decorated flower-like ZnO, we find that the PdO-ZnO sensor exhibits a response of 100 ppm C7H8 and C2H5OH, which is about 4-5 times higher than that of pristine ZnO at the optimal operating temperature of 240 and 320 degrees C. The enhanced sensing performance demonstrates that the distinct increases in response are attributed to the sensitisation effect of PdO. The effects of PdO decorating on the sensing properties of flower-like ZnO structures have been investigated. (C) 2012 Elsevier B.V. All rights reserved.