High Response Gas Sensors for Formaldehyde Based on Er-doped In2O3 Nanotubes

Pure and Er-doped In 2 O 3 nanotubes were systematically fabricated by using a single nozzle eletrospinning method followed by calcination . The as-synthesized nanotubes were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectrometry and X-ray powder diffraction (XRD). Compared with pure In 2 O 3 nanotubes, Er-doped In 2 O 3 nanotubes exhibit improved formaldehyde sensing properties at 260 °C. The response of Er-doped In 2 O 3 nanotubes to 20 ppm formaldehyde is about 12, which is 4 times larger than that of pure In 2 O 3 nanotubes. The response and recovery times of Er-doped In 2 O 3 nanotubes to 20 ppm formaldehyde are about 5 and 38 s, respectively. Furthermore, the response of Er-doped In 2 O 3 nanotubes to 100 ppb formaldehyde is 2.19.