Facile assembly of Au nanoparticles modified hierarchical mesoporous In2O3 for highly sensitive ethanol gas detection.

Flower-like In(OH) 3 was synthesized by a facile homogeneous precipitation method and subsequently calcined at 300 °C to prepare nanosheets assembled 3D flower-like mesoporous In 2 O 3 , which was then modified with Au nanoparticles via sol-immobilization method to produce 3D hierarchical mesoporous Au/In 2 O 3 for ethanol detection. The as-prepared Au/In 2 O 3 were carefully characterized by XRD, SEM, HRTEM and XPS techniques. The flower-like structure was assembled by many ultrathin coarse mesoporous In 2 O 3 nanosheets, and Au nanoparticles with an average size of 3.3 nm were evenly dispersed on In 2 O 3 nanosheets. The 3D flower-like mesoporous 1%Au/In 2 O 3 has a high specific surface area of about 130 m2 g−1 and shows the best sensitivity to ethanol among the flower-like mesoporous Au/In 2 O 3 materials. It can sensitively detect ethanol gas at a relatively low temperature of 160 °C with a response of 115–50 ppm ethanol, increased by nearly 11 times compared to In 2 O 3 at 210 °C. The 3D flower-like mesoporous 1%Au/In 2 O 3 also has good selectivity to ethanol with response about 9.4, 26.1, 20.9 and 29.5 times higher than that to acetone, methanol, toluene and xylene, and it displays excellent linear relationship between the response and the ethanol concentration. The markedly improved sensitivity and selectivity of the 3D flower-like mesoporous 1%Au/In 2 O 3 results from both the electronic sensitization and chemical sensitization effects of Au nanoparticles. In short, the 3D flower-like mesoporous 1%Au/In 2 O 3 possesses excellent sensitivity, selectivity, repeatability, linear relationship and long-term stability at 160 °C. Therefore, the obtained 3D flower-like mesoporous 1%Au/In 2 O 3 has great potential for ethanol gas detection. [Display omitted] • 3D flower-like mesoporous In 2 O 3 was synthesized via facile precipitation and calcination process. • 3D flower-like mesoporous Au/In 2 O 3 was prepared by sol-immobilization method. • 3D flower-like mesoporous Au/In 2 O 3 showed excellent ethanol sensing performance. [ABSTRACT FROM AUTHOR]