In2O3 porous microtubes derived from orientedly assembled MIL-68-In tubes via facile water etching for enhanced NO2 sensing performance at low temperature

Abstract

The porous and tubular structure is conducive to improving performance of sensing materials. At present, how to obtain sensitive materials with unique porosity and high surface activity by green, low-cost and simple synthesis methods is still a challenge. In this work, novel In₂O₃ porous microtubes were obtained by water etching of MIL-68-In and calcination methods for the first time. The as-prepared microtubes exhibit excellent NO₂ sensitivity at 50 ℃ (S=156 to 3 ppm NO₂), and the limit of detection is 50 ppb. The sensor also has good NO₂ detection ability in the actual environment. The excellent NO₂ sensing performance at low temperature is closely related to high surface activity of In₂O₃ porous microtubes. Combined with TPD, in-stiu DRIFT and XPS technologies, the NO₂ sensing mechanism was detailed analyzed. This work provides useful guidance for constructing high performance NO₂ sensor. The excellent NO₂ sensing performance at low temperature makes a positive contribution to promoting the application of metal oxide sensors in environmental detection.