In2O3-SnO2 hybrid porous nanostructures delivering enhanced formaldehyde sensing performance

Novel In2O3-SnO2 hybrid sensing nanostructures with porous nature were successfully prepared and characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM). Gas sensing properties of the fabricated sensor based on the as-prepared In2O3-SnO2 hybrid nanostructures were systematically investigated and compared with those of pure SnO2. The hybrid nanostructures containing 3% In2O3 exhibit the highest response value of 30.7-100 ppm formaldehyde at 100 °C, which was 14 times higher than that of pure SnO2. Moreover, gas sensors based on the as-prepared In2O3-SnO2 hybrid nanostructures also exhibit high stability and good selectivity for formaldehyde. The enhanced sensing performances of formaldehyde were mainly attributed to the formation of n-n heterojunctions and the synergistic interaction between In2O3 and SnO2.