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Tungsten oxide nanostructures functionalized with gold or platinum NPs are synthesized and integrated, using a single-step method via aerosol-assisted chemical vapour deposition, onto micro-electromechanical system (MEMS)-based gas-sensor platforms. This co-deposition method is demonstrated to be an effective route to incorporate metal nanoparticles (NP) or combinations of metal NPs into nanostructured materials, resulting in an attractive way of tuning functionality in metal oxides (MOX). The results show variations in electronic and sensing properties of tungsten oxide according to the metal NPs introduced, which are used to discriminate effectively analytes (C2H5OH, H2, and CO) that are present in proton-exchange fuel cells. Improved sensing characteristics, in particular to H2, are observed at 250 °C with Pt-functionalized tungsten oxide films, whereas non-functionalized tungsten oxide films show responses to low concentrations of CO at low temperatures. Differences in the sensing characteristics of these films are attributed to the different reactivities of metal NPs (Au and Pt), and to the degree of electronic interaction at the MOX/metal NP interface. The method presented in this work has advantages over other methods of integrating nanomaterials and devices, of having fewer processing steps, relatively low processing temperature, and no requirement for substrate pre-treatment. [ABSTRACT FROM AUTHOR]

Abstract: A new method of synthesising nano-particle-functionalised nanostructured materials via Aerosol Assisted Chemical Vapour Deposition (AACVD) has been used to grow WO3 nano-needles. Co-deposition of Gold (Au) nanoparticles with WO3 nano-needles has been implemented to deposit a sensing layer, which has shown surface plasmon resonance. The performed optical and structural studies had demonstrated that these materials have a high potential for an optical gas sensing. [Copyright &y& Elsevier]

A new method of synthesising nanoparticle-functionalised nanostructured materials viaAerosol Assisted Chemical Vapour Deposition (AACVD) has been developed. Co-deposition of Au nanoparticles with WO3nanoneedles has been used to deposit a sensing layer directly onto gas sensor substrates providing devices with a six-fold increase in response to low concentrations of a test analyte (ethanol). [ABSTRACT FROM AUTHOR]

Abstract: We have prepared tungsten oxide films decorated with gold particles on Si substrates by aerosol assisted chemical vapor deposition (AACVD) and characterized them using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). SEM shows that the films are composed of needle-like structures and TEM shows that both the needles and the gold particles are crystalline. XPS indicates the presence of oxygen vacancies, i.e. the films are WO3−x , and hence the deposited material is composed of semiconducting nanostructures and that the interaction between the gold particles and the WO3 needles surface is weak. The synthesis of semiconducting tungsten oxide nanostructures decorated with metal particles represents an important step towards the development of sensing devices with optimal properties. [Copyright &y& Elsevier]

A new method of synthesising nanoparticle-functionalised nanostructured materials via Aerosol Assisted Chemical Vapour Deposition (AACVD) has been developed. Co-deposition of Au nanoparticles with WO(3) nanoneedles has been used to deposit a sensing layer directly onto gas sensor substrates providing devices with a six-fold increase in response to low concentrations of a test analyte (ethanol).