▎ 摘　　要

A chemical sensor composed of Ni/Fe3O4, graphene, and polyaniline with enhanced acetone sensing performance was synthesized. Three types of sensing materials were prepared via a hydrothermal route: nanorod-shaped Ni/Fe3O4 (NIF), Ni/Fe3O4 -graphene (NIFG), and Ni/Fe3O4 -graphene-polyaniline (NIFGP). Both graphene and polyaniline were added to confer sufficient electron conductivity upon the reaction with gas by decreasing the bandgap of the composite, while the hydrophobic polyaniline improved the structural integrity and insensitivity to ambient moisture. The NIFGP sensor fabricated based on these postulations showed a higher sensitivity for 0.001-400 ppm acetone than the NIF nanorods and excellent selectivity, showing a negligible response to toluene and ethanol. This sensor can be applied to the simple detection of diabetes non-invasively using urine and breath analysis. A mechanism for the enhanced acetone sensitivity of NIFGP is suggested.