Efficient Gas-Sensing for Formaldehyde with 3D Hierarchical Co₃O₄ Derived from Co₅-Based MOF Microcrystals

Detecting formaldehyde at low operating temperature and maintaining long-term stability are of great significance. In this work, a hierarchical Co₃O₄ nanostructure has been fabricated by calcining Co₅-based metal-organic framework (MOF) microcrystals. Co₃O₄-350 particles were used for efficient gas-sensing for the detecting of formaldehyde vapor at lower working temperature (170 °C), low detection limit of 10 ppm, and long-term stability (30 days), which not only is the optimal value among all reported pure Co₃O₄ sensing materials for the detection of formaldehyde but also is superior to that of majority of Co₃O₄-based composites. Such extraordinarily efficient properties might be resulted from hierarchically structures, larger surface area and unique pore structure. This strategy is further confirmed that MOFs, especially Co-clusters MOFs, could be used as precursor to synthesize 3D nanostructure metal oxide materials with high-performance, which possess high porosity and more active sites and shorter ionic diffusion lengths.