The enhanced NO sensing properties of SnO nanoparticles/reduced graphene oxide composite.

Multiple techniques were utilized to characterize the structure and morphology of the SnO/reduced graphene oxide (rGO) composite, in which the composite was prepared by a facile one-pot microwave-assisted hydrothermal method. As a result, SnO nanoparticles with diameters of 3-5 nm were anchored uniformly on both sides of the rGO sheets. Meanwhile, a series of resistive-type gas sensors based on SnO/rGO composite and pure SnO were fabricated and tested for analyzing the effects on introducing rGO. The results revealed that, the composite exhibited obviously enhanced gas sensing properties towards NO with high response, fast response and recovery speed, and good selectivity and reproducibility. At 75 °C, the response of the composite to 350 ppb NO was about 6.6 times of that to pure SnO. In addition, the response and recovery time of the sensor was greatly reduced from 39.2/54.7 to 6.5/1 min, and the detecting limit of the sensor was even as low as 50 ppb. Provided with the enlarged surface area and local p-n heterojunctions, the synergistic effect of SnO nanoparticles and rGO contributed to the enhanced gas sensing properties of SnO/rGO composite.