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.