High sensitive gas sensor based on Pd-loaded WO3 nanolamellae

An impregnation method has been proposed to prepare Pd-loadedWO3 nanolamellae for the gas sensing application. WO3 nanolamellaewere synthesized via an acidificationmethod and impregnatedwithH(2)Pd(2)Cl(4) solution followed by an ammoniawashing treatment. Themicrostructure and H2 sensing characteristics of the Pd-loaded WO3 nanolamellae were investigated. Electronmicroscopy studies revealed that PdO particles have been deposited on the surfaces ofWO(3) with a diameter ranging from3 to 15 nm. With quite a small amount of Pd, the sensor resistivity was greatly enhanced and it demonstrated an extremely large response to the reduced gas. It was found that sensing response at low temperature increased dramatically with a rise in the gas concentration for Pd-loaded sensors. However, the sensor response at high temperature quickly saturated with increasing the H-2 concentration for larger amount of Pd loading. An enhanced combustion effect of Pd and chemical adsorbed water could be responsible for such a saturation of sensing response at high temperatures. (C) 2013 Elsevier B.V. All rights reserved.