Facile synthesis of nanoparticle packed In 2 O 3 nanospheres for highly sensitive NO 2 sensing

Nanoparticle packed In 2 O 3 nanospheres are successfully synthesized via a facile one-step solvothermal method followed by annealing. The structure and morphology of the as-synthesized samples are characterized via X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Moreover, the NO 2 gas sensing properties of the nanoparticle packed In 2 O 3 nanospheres are further investigated. The sensor shows excellent selectivity, high response (217.5 to 500 ppb), superior stability and repeatability at the optimum operating temperature of 120 °C with a limit of detection lower than 10 ppb. Thus, this type of material is promising for low concentration NO 2 gas-sensing.