Facile Synthesis of Polyaniline/Carbon-Coated Hollow Indium Oxide Nanofiber Composite with Highly Sensitive Ammonia Gas Sensor at the Room Temperature.

Hollow carbon-coated In 2 O 3 (C#In 2 O 3 ) nanofibers were prepared using an efficiently combined approach of electrospinning, high-temperature calcination, and hydrothermal process. The polyaniline (PANI)/hollow C#In 2 O 3 nanofiber composites were synthesized used hollow C#In 2 O 3 nanofibers worked as a core through the in situ chemical oxidative polymerization. The morphology and crystalline structure of the PANI/hollow C#In 2 O 3 nanofiber composite were identified using wide-angle X-ray diffraction and transmission electron microscopy. The gas-sensing performances of the fabricated PANI/hollow C#In 2 O 3 nanofiber composite sensor were estimated at room temperature, and the response value of the composite sensor with an exposure of 1 ppm NH 3 was 18.2, which was about 5.74 times larger than that of the pure PANI sensor. The PANI/hollow C#In 2 O 3 nanofiber composite sensor was demonstrated to be highly sensitive to the detection of NH 3 in the concentration range of 0.6~2.0 ppm, which is critical for kidney or hepatic disease detection from the human breath. This composite sensor also displayed superior repeatability and selectivity at room temperature with exposures of 1.0 and 2.0 ppm NH 3 . Because of the outstanding repeatability and selectivity to the detection of NH 3 at 1.0 and 2.0 ppm confirmed in this investigation, the PANI/hollow C#In 2 O 3 nanofiber composite sensor will be considered as a favorable gas-sensing material for kidney or hepatic disease detection from human breath.