Metal-organic framework-derived mesoporous rGO-ZnO composite nanofibers for enhanced isopropanol sensing properties

Metal-organic framework (MOF)-derived porous reduced graphene oxide (rGO)-ZnO composite nanofibers (NFs) were fabricated by using rGO and zeolitic imidazolate framework-8 (ZIF-8) as electrospun precursors. The prepared materials were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrum (XPS), ultraviolet photoelectron spec-troscopy (UPS), and the Brunauer-Emmet-Teller (BET) method, respectively. This innovative rGO-ZnO com-posite NFs integrated the advantages of two kinds of porous material (MOFs and NFs), thereby displayed high density and large-size mesopores. Sensing results indicated that the 3 mL rGO-ZnO NFs demonstrated good sensing properties characterized by higher isopropanol (IPA) sensing responses (2.8-fold improvement @ 50 ppm) and faster response/recovery times (14 s/39 s) in comparison with pure ZnO nanocages. In addition, good selectivity and stability towards IPA of the 3 mL rGO-ZnO NFs were also observed. High IPA sensing properties were attributed to the synergic coupling between rGO nanosheets and ZnO nanoparticles, as well as the unique MOF-derived 3D mesh nanofiber structure with large-size mesopores, high surface area, and anti-aggregation property. This study presents a new approach for constructing MOF-derived porous rGO-metal oxide compos-ite mesh NFs sensing materials with high-performances.