Enhanced methane sensing performance of Ag modified In2O3 microspheres

Abstract In2O3 and Ag/In2O3 with diverse doping content were synthesized by a solvothermal method and the subsequent calcination process. Some characterizing methods were used to ensure the obtained materials including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Such analysis indicated that all materials were synthesized successfully and mostly as-synthesized materials are formed with the diameter of 300-450 nm. A contrastive study for CH4 gas sensing performance of pure In2O3 and. Ag/In2O3 was carried out. The sensor test showed that, a high performance based on Ag-doping In2O3 microspheres toward CH4 was obtained. Especially, the 6%-Ag/In2O3 based sensor can detect 500 ppm CH4 with a high response of 27.46, which is about two times of pure In2O3 sensor. The sensors sensitized by Ag possessed a low operation temperature, a better selectivity, even could detect CH4 in a wide concentration range. The possible mechanism such as chemical sensitization and electronic sensitization of Ag nanoparticles was discussed. The 6%-Ag/In2O3 composite exhibited a superior detection performance, which is promising for a real-time CH4 sensor.