| Carbon nanofibers（CNFs）with large specific surface area,large aspect ratio,good electrical conductivity and unique one-dimensional nanostructures have promising applications in energy storage,catalysis and sensors.And carbon nanofibers can be modified by various physical and chemical methods to construct functionalized composite films due to their unique base graphite surface and edge surface.Firstly,the continuous nanofiber film with cobalt 2-methylimidazole（ZIF-67）nanoparticles embedded in the polyacrylonitrile（PAN）was prepared by simply electrospinning.Then,CNFs/Co nanofibers film was synthesized via the pre-oxidation and carbonization.Finally,two-dimensional Mo S2 nanosheets was vertically grown on the nanofibers and Co S2 nanoparticles from cobalt metal were dispersed on the nanosheets and nanofibers,building a network self-support composite film（CNFs/Co S2/Mo S2）.This method was simple and low-cost and can control the loading of Mo S2 by controlling molybdenum source concentration.The surface morphology,internal structure and elemental distribution of the samples were analyzed by a series of characterization methods,s uch as scanning electron microscope,transmission electron microscope,X ray diffraction analysis and X ray photoelectron spectroscopy.The gas sensor based on CNFs/Co S2/Mo S2 was composed of carbon nanofibers as substrates of flexible conductive networks,Mo S2 nanosheets and Co S2nanoparticles act as sensitizer and catalyst,which exhibited excellent selectivity to NO and excellent stability.The response（-19%）of CNFs/Co S2/Mo S2 at 50 ppm NO was 2.7 times and 3.17 times of CNFs/Mo S2 and carbon nanofibers sensors.Moreover,the sensor had a low limit of detection down 1 ppm and linear in the gas concentration range of 1～100 ppm.In addition,the CNFs/Co S2/Mo S2 composite films can be bent to large angles repeatedly while maintaining stable response,indicating that the mechanical deformation had little effect on the performance of the sensor.Furthermore,the CNFs/Co S2/Mo S2 shown a specific capacitance of 640 F/g at the current density of 1 A/g,and it was still as high as 416 F/g at 8 A/g,which were52 and 3.06 times that of CNFs/Co S2 and CNFs/Mo S2.The CNFs/Co S2/Mo S2electrode expressed cycling ability with 80%capacitance retention after 2000 cycles of charge-discharge at current density of 8 A/g. |
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