Facile synthesis of Ag nanoparticles-decorated WO3 nanorods and their application in O2 sensing

Here we describe a two-step aerosol-assisted chemical vapor deposition (AACVD) synthesis method for the fabrication of Ag nanoparticles (NPs) decorated WO3 nanorods (NRs), evaluating the use of different organometallic silver precursors. Physical property characterization techniques including XRD, SEM, TEM, and XPS were carried out to investigate the composition and morphology of the pristine WO3 NRs and functionalized WO3 NRs with Ag NPs. The results showed that uniform WO3 NRs were obtained with a length of 600 nm to several μm and a diameter of 100–200 nm, and Ag NPs were well-dispersed on the surface of WO3 NRs with the size of 6–20 nm. The nanostructured WO3 thin films were synthesized and integrated directly onto alumina platforms via the AACVD method to fabricate gas sensors. Gas sensing performance was investigated towards different O2 concentrations between 1% and 20% at various operating temperatures. The sensing response revealed that an increase in baseline resistance was observed for the Ag-decorated WO3 sensors fabricated by using organometallic silver precursors, and the decoration of Ag NPs on WO3 sensors improved sensing properties as compared to the undecorated ones. The possible formation process and sensing mechanism of the Ag NPs decorated WO3 NRs are proposed.