WO3 Nanowires Loaded with Cobalt Oxide Nanoparticles, Deposited by a Two-Step AACVD for Gas Sensing Applications

Abstract A two-step procedure was implemented to obtain tungsten oxide nanowires (WO3) doped with cobalt oxide nanoparticles employing W(CO)6 and the metal-organic precursor Co(acac)2. In the first step, tungsten oxide nanowires were grown at 400 oC using an aerosol assisted chemical vapor deposition system (AA-CVD) and subsequently annealed at 500 oC for 2 hours in dry air. Then, cobalt oxide loading (at different dose levels) of the nanowires was performed via a second AA-CVD process. These hybrid nanomaterials were grown on top of commercial alumina substrates that comprised interdigitated electrodes and a heating element. The response of these nanomaterials toward H2S, ethanol H2 and ammonia is investigated and discussed. Co-loaded tungsten oxide is well suited for detecting ammonia under dry conditions and hydrogen sulfide in humid environments.