Au decoration of vertical hematite nanotube arrays for further selective detection of acetone in exhaled breath.

Highlights • The synthesis of high performance gas sensors based on hematite nanotubes with Au catalyst has been demonstrated. • The Au decorated hematite gas sensor exhibits highly sensitive detection to acetone. • The highly improved sensitivity and selectivity in wet air are attributed to the spill-over effect by the Au catalyst. Abstract Vertically ordered hematite nanotubes decorated with Au nanoparticles are synthesized by a facile electrochemical anodization method and self-agglomeration of Au films. Au decoration significantly enhances the response of hematite nanotubes to acetone at 350 °C and the response to acetone is 2.4 times higher than the response to ethanol, the counterpart target gas. The Au nanoparticles decorated hematite nanotubes exhibit unprecedentedly high and selective responses to acetone at 350 °C with 50% relative humidity condition (calibrated at room temperature, 25 °C). The enhanced gas sensing properties in a humid condition were attributed to the spillover effect by Au nanoparticles and high porosity of hematite nanotubes with a large surface-to-volume ratio. These results indicate that Au nanoparticles decorated hematite nanotubes are promising for use in high quality sensor materials for breath analyzers to diagnose diabetes mellitus. [ABSTRACT FROM AUTHOR]