Preparation of porous flower-like graded structure Co ₃ O ₄ /g-C ₃ N ₄ and its ethanol gas-sensitive properties

The porous flower-like structure of Co 3 O 4 and Co 3 O 4 /g-C 3 N 4 composites derived from the cobalt-based metal organic framework (MOF) were prepared by one-step hydrothermal method and high temperature calcination, and the gas sensitivity of the synthesized samples to ethanol gas was tested. The structure and morphology of the synthesized samples were characterized via X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and N 2 adsorption-desorption. The gas-sensitive properties of the synthesized samples for ethanol gas were tested. It was demonstrated that the response of Co 3 O 4 /g-C 3 N 4 to 100 ppm ethanol at 220°C was 36.33, which was 1.5 times higher than that of pure Co 3 O 4 . In addition, this gas sensor exhibited excellent selectivity, good repeatability, and long-term stability for ethanol. The gas-sensitive properties of the Co 3 O 4 /g-C 3 N 4 graded structure towards ethanol were attributed to the unique porous graded structure of the material, the large specific surface area and the p-n heterojunction. This method provided a new idea for the porous flower-like hierarchical structure of metal oxide semiconductors (MOS) derived from MOFs.