MOF-derived Co3O4 hierarchical porous structure for enhanced acetone sensing performance with high sensitivity and low detection limit

Metal organic frameworks (MOFs) with unique interior structure play a significant role in the field of gas-sensing. In this research, Co 3 O 4 - x hierarchical porous structure is successfully prepared by the solvothermal method and subsequent heat treatment using MOF as a sacrificial template. The effect of cobalt sources with different proportions of cobalt nitrate and cobalt chloride on the morphology, structure and gas-sensing of as-prepared Co 3 O 4 - x ( x  = 0, 1, 2, 3) samples is characterized and investigated in details by various techniques of XRD , Raman, SEM, TEM, BET and XPS . The findings demonstrate that the typical Co 3 O 4 -2 sensor exhibits a significantly higher response (27.6) than Co 3 O 4 -0 (6.1) to 50 ppm acetone at 140 °C. Furthermore, Co 3 O 4 -2 sensor exhibits fairly low detection limit of 0.1 ppm, superior selectivity, repeatability, and long-term stability. The optimized acetone-sensing capability of the as-obtained Co 3 O 4 - x samples may be ascribed to the hierarchical porous structure composed of the adhered nanoparticles due to the slow dissolution of CoCl 2 ·6H 2 O, which is beneficial to increasing electron transport channels, thus improving gas sensitivity. The work provides a new idea for the preparation of respiratory monitoring materials for diabetic patients.