LAUSR

Abstract A series of the rGO decorated hollow Co 3 O 4 spheres were fabricated via a solvothermal-combination-calcination process with no template. The morphological and crystal structure analysis were carried out through several characterization techniques, including SEM, TEM, XRD and XPS. The results indicate that the hollow Co 3 O 4 microspheres were assembled by nanoparticles with an average diameter of 20 nm and adhered uniformly on rGO nanosheets. According to the gas sensing test, 3 wt% rGO-Co 3 O 4 hollow spheres showed a higher substantial response to 100 ppm ethanol reaching up to 13.5, which is 3.7 times than the pristine Co 3 O 4 at 180 °C. In addition, it also exhibited short response-recovery time and good reproducibility. The enhanced sensing properties probably come from the synergy between rGO and Co 3 O 4 , mesoporous structure, and its high specific surface area (108.2 m 2 /g). This facile method could be used for the fabrication of many advanced materials for sensors, capacitors and electrodes.