Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites

摘要

As an ethanol sensing material, the composites of In2O3-SnO2 were composed of In2O3 microflowers and SnO2 nanoparticles. Both In2O3 microflowers and SnO2 nanoparticles were synthesized by hydrothermal method and then mixed in an ultrasonic environment. The morphology and phase composition of the as-synthesized samples were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results on gas sensing properties showed that when the mass ratio of In2O3 and SnO2 was 2 : 1, the sensor based on the as-prepared In2O3-SnO2 composite exhibited high response and good selectivity to ethanol at 250 degrees C. The response to 100 ppm ethanol gas was 53.2. UV illumination stabilized the responses of the sensors while the relative humidity increased. The gas sensing mechanism proposed was that the addition of SnO2 to In2O3 enhanced the catalytic activity for the ethanol reaction, which changed the electrical resistance of the materials. Besides, the morphology was helpful to the gas reaction on the surface of the sensing materials.