Enhanced acetone sensing of MOFs derived Co3O4-ZIF hierarchical structure under the strategy of internal construction and external modification

Co3O4-ZIF-x (x = 0,1,2,3) composites have been prepared by in-situ growth of ZIF membrane on MOFs-derived hierarchical porous Co3O4 by the solvothermal method with adjusting the ratio of dimethylimidazole. The effects of ZIF membrane on Co3O4 structure and acetone-sensing properties are investigated by the techniques of XRD, Raman, SEM, TEM, BET, XPS and performance testing, and the possible gas-sensing enhancement mechanism is analyzed. The results show that the typical Co3O4-ZIF-1 sensor has the maximum response of 77.8–50 ppm acetone at 180 °C, the short response/recovery time of 7/35 s, and the low detection limit of 0.1 ppm (3.28). It also has the reliable acetone selectivity against to other interfering gases, as well as good repeatability and high stability. Its enhanced acetone-sensing property may be attributed to the synergistic effect of the improved surface state, high specific surface area, adjustable pore size and rich reaction activation sites, which caused by the hierarchical porous structure of MOFs-derived Co3O4 and the gas adsorption and enrichment effect of ZIF membrane, promoting the further reaction and diffusion of acetone. The “internal construction and external modification” role of MOFs playing in Co3O4 provides a new idea for designing high performance sensing materials.