Porous cube-like In₂O₃ nanoparticles and their sensing characteristics toward ethanol

Porous cube-like crystalline In₂O₃ nanoparticles with an average diagonal length of 34.8 nm were fabricated by a laser ablation-reflux process to form In(OH)₃, followed by a calcination treatment to yield porous In₂O₃. HRTEM (high-resolution transmission electronic microscopy), XRD (X-ray diffraction), BET (Brunauer-Emmett-Teller), and XPS (X-ray photoelectron spectroscopy) analysis were used to characterize their crystalline structures, grain sizes, surface areas, and surface compositions. The as-prepared porous indium oxides were tested for their sensing properties toward ethanol. Non-porous In₂O₃ nanopowder (about 40 nm) was also examined in order to compare the results with the as-prepared porous In₂O₃ nanomaterials. The porous In₂O₃ exhibited much better performance than that of non-porosus In₂O₃, and showed enhanced sensitivity with a lower detection limit than other reported In₂O₃-based materials when exposed to ethanol. Good gas sensitivity and linear behavior as a function of ethanol concentration were observed in the porous In₂O₃ nanoparticles.