Constructing of Bi2O3-In2O3 nanofibers for sensitive detection of freshness gas markers in aquatic products

In order to quickly and accurately detect and then evaluate the freshness of fish, trimethylamine is used as a landmark gas for detection. In this study, an alternative trimethylamine chemosensor based on Bi 2 O 3 -In 2 O 3 nanofibers (NFs) was synthesized successfully through the electrospinning method. The structure, morphology and chemical states of Bi 2 O 3 -In 2 O 3 NFs were characterized. The results of gas sensing tests indicated that after doping In 2 O 3 with 3 % Bi 2 O 3 , the sensor displays better sensitivity to trimethylamine (48.6–100 ppm), which was 2.9 times higher than pure In 2 O 3 (NTs) gas sensor (16.4) at the optimal operating temperature of 250 °C. Under low concentrations of trimethylamine (0.5 ppm), the 3 % Bi 2 O 3 -In 2 O 3 NFs sensor still has a specific sensitivity (1.3). The increased sensitivity of 3 % Bi 2 O 3 -In 2 O 3 NFs sensor is attributed to the increase of oxygen vacancy, which can be confirmed by XPS and UV- vis methods. The sensor sensitivity decreased as the relative humidity increased, but the response remained at approximately 10 even under a high humidity environment of 90 %. The excellent performances towards trimethylamine indicate that 3 % Bi 2 O 3 -In 2 O 3 NFs are prospective candidates for trimethylamine gas sensor fabrication.