Porous Zn-doped In2O3 nanobelts for ppb level acetone sensing at low operating temperature

Porous zinc doped indium oxide (Zn-In 2 O 3 ) nanobelts were synthesized using a straightforward hydrothermal method. The effects of different metal doping (Zn, Sn, Sm, Yb, Cu) and various concentrations of Zn on the morphology and gas-sensing properties of In 2 O 3 were investigated. The gas sensing evaluations reveal that among all tested sensors, the porous 7.5% Zn-In 2 O 3 nanobelt sensor exhibits the highest response, reaching 127 (S= R a / R g ) to 50 ppm acetone at a low operating temperature of 140°C, which is approximately 21 times greater than that of pure In 2 O 3 . Additionally, this sensor demonstrates rapid response/recovery time, a low detection limit of 40 ppb, good selectivity, excellent repeatability, and long-term stability toward acetone. In-situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and density functional theory (DFT) calculations are employed to elucidate the mechanisms behind the enhanced gas-sensing performance of the porous Zn-In 2 O 3 nanobelts. The superior gas-sensing characteristics are attributed to the distinctive porous nanobelt architecture, abundant oxygen vacancies, large specific surface area, and the effects of Zn doping.