Room-temperature, high selectivity and low-ppm-level triethylamine sensor assembled with Au decahedrons-decorated porous α-Fe2O3 nanorods directly grown on flat substrate

Abstract

Chemiresistive based gas sensors with low operating temperature (e.g. room-temperature), high selectivity, and fast response for specific target gas are highly desired. Herein, we successfully construct triethylamine (TEA) gas sensors with gold (Au) decahedrons (DHs)-decorated porous α-Fe2O3 nanorods, which can work at 40 °C and exhibit high selectivity and low-ppm-level response. Porous α-Fe2O3 nanorods with high specific surface area are directly grown on seeded flat substrate with electrodes by a cost-effective hydrothermal method. Au DHs synthesized by one-pot polyol reaction method are deposited onto such α-Fe2O3 nanorods by spin-coating. Such Au DHs/α-Fe2O3 nanorods sensor working at temperature as low as 40 °C and relative humidity (RH) of 30% exhibits high response (17–50 ppm TEA), low detection concentration (∼1 ppm), and short response/recovery time (12/8 s), which are all much better than the control α-Fe2O3 nanorods sensor. When the RH increases, the sensor response decreases due to the water molecules adsorption. Furthermore, the enhanced sensing properties toward TEA are discussed in terms of the formation of Au/Fe2O3 metal/semiconductor Schottky contact and the catalytic activity of Au DHs.