Low-Temperature Detection of Sulfur-Hexafluoride Decomposition Products Using Octahedral Co3O4-Modified NiSnO3 Nanofibers

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.

Enhanced Acetone-Sensing Properties of Pt-Decorated In2O3 Hollow Microspheres Derived from Pt-Embedded Template

Pt-decorated In2O3 hollow microspheres were prepared using a template and reflux method. The size of the prepared carbon templates was adjusted from 200 nm to 1.3 μm by introducing chloroplatinic acid during the hydrothermal process. At the same time, Pt nanoparticles inside the carbon layer were protected from oxidation and agglomeration. Also, the folds created on the surface of the hollow sphere during shrinkage led to a substantial increase in specific surface area. The response of the In2O3-based sensor toward acetone was significantly enhanced by the addition of Pt decoration. This improvement can be attributed to the increased availability of active sites for the target gas and the consequential alteration of the energy band structure. In addition, high response sensitivity, rapid dynamic processes, long-term reliability, and selectivity have all been achieved. The detectable limit is less than 1 ppm, which might satisfy the 1.8 ppm threshold value in the exhaled breath of patients with diabetes. Consequently, the proposed sensor has great sensitivity and can detect low-concentration of acetone, making it an ideal choice for applications such as monitoring daily dietary intake, managing diabetes, and inspecting industrial production processes.