High responsive n-butanol gas sensor based on MOFs-derived Cr₂O₃/RGO p-p heterojunctions materials

Metal-organic frameworks (MOFs)-derived metal oxide semiconductors (MOSs) have garnered significant interest for their potential use in gas-sensitive materials, owing to their distinctive properties. Despite this, gas sensors derived from MOFs are still hindered by issues such as low sensitivity or poor selectivity. In this research, we address these challenges by integrating MOF-derived Cr₂O₃ nanoparticles with reduced graphene oxide (RGO) nanosheets to form p-p heterojunction composites, which significantly enhance the sensing capabilities for n-butanol gas detection. We employed a gravity-induced sedimentation technique coupled with the hydrothermal method to grow Cr₂O₃ nanoparticles on RGO nanosheets. The RGO nanosheets not only act as a substrate to prevent the agglomeration and stacking of Cr₂O₃ nanoparticles but also facilitate the formation of Cr₂O₃/RGO p-p heterojunctions. Consequently, the fabricated Cr₂O₃/RGO sensor, with a GO weight fraction of 2.9 wt%, demonstrated an impressive response of 121.2–100 ppm n-butanol gas at 160°C, which is an eightfold increase over a sensor composed solely of Cr₂O₃. The theoretical detection limit was determined to be as low as 8.6 parts per billion (ppb). The study concludes with a discussion on the potential sensing mechanism of the Cr₂O₃/RGO composites that contribute to the enhanced performance. The findings of this research are expected to significantly advance the development and application of n-butanol detection technology.