Porous nanosheet-assembled Zn3Mo2O9 microflowers for high-selectivity detection of ethanol vapor.

• Porous Zn3Mo2O9 microflowers assembled with cross-linked nanosheets are synthesized using a facile hydrothermal method combined with calcination. • Porous flower-like microstructures are constructed by numerous cross-linked nanosheets as building blocks. • Gas sensor based on porous Zn3Mo2O9 microflowers exhibits good sensing performances for volatile organic gases (VOCs), especially for the high selectivity of ethanol gas. • The larger available surface area, favorable hierarchical flower-like microstructure assembled by cross-linked nanosheets, larger pore size, and higher relative percentage of the OC and OV, and oxidative catalytic activation of metal elements all jointly contribute to superior sensing performances. Porous Zn 3 Mo 2 O 9 microflowers assembled with cross-linked nanosheets were synthesized using a facile hydrothermal method combined with calcination. Compared to pure MoO 3 nanorod sensor, the Zn 3 Mo 2 O 9 sensor exhibited a stronger response of 58.3 toward 100 ppm ethanol at 220 °C, with a shorter response/recovery times (10 s/14 s). The excellent stability and repeatability of the Zn 3 Mo 2 O 9 sensors were also demonstrated. The detected limit for the ethanol vapor was as low as 29 ppb. The superior ethanol sensing properties were attributed to favorable porous microflowers assembled by cross-linked nanosheets, higher porosity, large specific surface area, higher relative percentage of the O C and O V , and oxidative catalytic activation. This was advantageous for providing abundant surface active sites for the adsorption of gas molecules, as well as accelerating the oxidation of more ethanol molecules between oxygen species and ethanol gas. This study provides practical application for detecting alcohol gases. Porous flower-like Zn 3 Mo 2 O 9 microstructures consisting of uniform cross-linked nanosheets were synthesized using a facile hydrothermal method combined with calcination. The porous Zn 3 Mo 2 O 9 microflowers sensors presented a higher response (58.3), shorter response–recovery times (10 s/14 s), and lower working temperature (220 °C) for 100 ppm ethanol gas. The Zn 3 Mo 2 O 9 microflowers sensors also showed good responses toward other alcohol gases such as isopropanol, and methanol. The superior ethanol sensing properties were attributed to favorable porous microflowers assembled by cross-linked nanosheets, higher porosity, larger specific surface area, higher relative percentage of the O C and O V , and oxidative catalytic activation. [Display omitted] [ABSTRACT FROM AUTHOR]