▎ 摘　　要

Pristine SnO2 nanoparticles (NPs) and its composite with reduced graphene oxide (SnO2 NPs/rGO) have been successfully synthesized using a facile hydrothermal method. Prepared samples are characterized by X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller analysis, and Raman and photoluminescence spectroscopy. The results show that the average crystallite size of SnO2 NPs with tetragonal rutile structure decreased from about 14 to about 8 nm during the formation of SnO2 NPs/rGO nanocomposite. The resultant SnO2 NPs/rGO nanocomposite exhibits high surface area of 128.52 m(2)/g and large pore volume of 0.14 cm(3)/g with uniform pore size of 4.39 nm. The existence of electronic interactions caused by the formation of p-n heterojunctions between p-rGO and n-SnO2 NPs is confirmed by analysis results. SnO2 NPs/rGO nanocomposite sensing responses toward 600-1700 ppm of ethanol vapor at 130 degrees C are about 14-33 times higher than those of pristine SnO2 NPs at 210 degrees C. The nanocomposite sensor exhibits very low response time of below 3 s, good selectivity, and excellent long-term stability with the response decay of about 4% after 4 months. The improved sensing characteristics in SnO2 NPs/rGO nanocomposite can be attributed to the formation of p-n heterojunctions, small particles size, large specific surface area, and high porosity.