▎ 摘　　要

Graphene quantum dots (GQDs) were prepared by pyrolysis of citric acid. The sizes of the as-prepared GQDs were in the range of 2-4 nm. The GQDs/alpha-Fe2O3 composites were prepared by loading GQDs with alpha-Fe2O3 via a one-step facile hydrothermal method. The GQDs/alpha-Fe2O3 composites were characterized by XRD, TGA, FTIR, Raman, SEM and TEM, respectively. The sensor devices were fabricated using the GQDs/alpha-Fe2O3 composites as sensing materials. The effect of the amount of GQDs in the composites on the gas-sensing responses of the materials and the gas-sensing selectivity was investigated. The experimental results revealed that the sensor based on GQDs/alpha-Fe2O3 (S-15) composite exhibited high sensitivity and good selectivity to TMA vapor. The responses of the sensor based on GQDs/alpha-Fe2O3 (S-15) composite to 1000 ppm and 0.01 ppm TMA vapor attained 1033.0 and 1.9 at 270 degrees C, respectively. The response time and recovery time for 0.01 ppm TMA vapor were only 6 s and 4 s, respectively. (C) 2016 Published by Elsevier Inc.