▎ 摘　　要

The polyol method has been employed to fabricate a palladium-doped graphene-tin oxide composite as a highly sensitive and selective carbon monoxide gas sensor. The ratio of graphene-SnO2 which is used in this research is 1:1, while the concentration of Pd doping is varied at 0.1%, 0.5%, and 1%. X-ray diffractometry (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) have been used to analyze crystallinity and morphology of all samples. Thick-film Pd-doped graphene-SnO2 has been fabricated using the spin-coating method on an alumina substrate. Investigation of the effect of Pd doping on a 30-ppm CO sensor shows increasing response from 88.11 to 92.99% after adding 0.1% Pd at a working temperature of 150 degrees C. At 50 degrees C, responses of the composite graphene-SnO2 with 0.1%, 0.5%, and 1% Pd are 19.32%, 32.00%, and 24%, respectively. While at 250 degrees C, sensor responses of graphene-SnO2 composites with 0.1%, 0.5%, and 1% Pd are 99.89%, 92.93%, and 75.06%, respectively. Among the samples, the 0.1% Pd-doped graphene-SnO2 composite shows the highest response; as a result, 0.1% Pd becomes the optimum concentration of Pd doping. Moreover, the 0.1% Pd-doped graphene-SnO2 composite shows good sensor sensitivity at 1.73%/ppm and great selectivity toward CO gas.