Oxygen vacancies induced by lanthanum-doped indium oxide nanofibers for promoted temperature-dependent triethylamine and formaldehyde sensing

A novel TEA and HCHO dual-function temperature-dependent sensing material (3La-In₂O₃) with ultra-high sensitivity was developed via a facile electrospinning process. Though rare earth doped in In₂O₃-based sensors have been widely reported, the low sensitivity, poor selectivity and high operating temperature remain restrict their application. Herein, the In₂O₃ nanofibers with different contents of La³⁺ ions are firstly obtained by a facile electrospinning process. The sensing performance investigation confirms that the 3% La/In molar ratio of La³⁺ doped in In₂O₃ nanofibers are more appropriate as the sensing material for TEA and HCHO detection. The 3La-In₂O₃ exhibits greatest response value of 3721.60–10 ppm TEA and 1469.65–10 ppm HCHO at their best working temperature (100 ℃ and 160 ℃), approximately 23.85-fold and 10.85-fold higher than that of pristine In₂O₃ nanofibers. In addition, the excellent selectivity, repeatability, and long-term stability ensure the further application of the 3La-In₂O₃-based sensor in actual environment. The promoted sensing performance is mainly ascribed to the more oxygen vacancies, the increasing specific surface area, the smaller grain size of In₂O₃ nanofibers induced by La³⁺ doping. The DFT results demonstrate the beneficial effect of La and oxygen vacancies on the improved target gas adsorption energy.