Preparation Of Partial Graphitic Carbon Nanofibers And Their Catalytic Performance For NO Oxidation

In recent years,the concentration of NOx in air is ascending year by year with the acceleration of industrialization process and with increasing of motor vehicle quantity,which becomes serious to environment and health.Thus,it is important to study and develop novel materials for NOx removal.In this work,the carbon nanofibers(CNFs)are prepared by electrospinning,and the different CNFs with local graphitization were obtained by adding graphene oxide(GO)and treatment of catalytic graphitization at low temperature.The CNFs with excellent properties for NO catalytic oxidation at room temperature were obtained by adjusting and controlling the specific surface area(SSA),pore structure and degree of graphitization.The GO and PAN as precursors were used to prepare C/C hybrid nanofibers by an electrospinning process,during the treatment in NH3,GO sheets were reduced to form rGO which as active sites embedding in CNFs.Compared to the pure PAN-based CNFs,the rGO/PAN hybrid nanofibers enable higher catalytic activity for NO oxidation.The influence of relative amount of GO on NO catalytic property also was study,when the amount of GO is 5 wt% NO present the highest conversion rate(Rc)to NO2,up to 47.5%,and the highest additive amount of GO in PAN is 30 wt%.a large amount of nitrogen-containing functional groups can be introduced in CNFs by NH3 treatment,which can improve the catalytic activity for NO oxidation obviously,compared to H2 O treatment the Rc was promoted 7.9% additionally.The graphene based nanofibers was obtained by electrospinning GO and PAN precursors followed by NH3 treatment at 900 and 950? with 20,30,40 and 50 min,in which,the GO was prepared with flake graphite.A large number of mesopores were introduced by NH3 treatment at 950?,which lead the SSA declined clearly.The degree of graphitization for CNFs depends on the temperature and time with NH3 treatment.The highest Rc was obtained by NH3 treatment 50 min at 900?,get to 49.5%,which in proportion to the degree of graphitization.Compared to the pure CNFs,the graphene based CNFs can enhance the Rc of NO 13% additionally.The excellent effect for PAN based CNFs was gained by addition of AAI and treated at 1000?.When the treat temperature is fixed,the addition amount of AAI has little effect on catalytic graphitization,and while the amount of AAI is fixed,the treat temperature play an key role on catalytic graphitization.It can be observed from the CNFs there is less than 10 nm thick graphite stripe twine around Fe particle,which make the CNFs forming the graphite structure.The SSA can be increased up to 1300 m2/g by NH3 treatment at 900?,which is two times of that treated at 1000?.While the addition amount of AAI get to 15 wt%,the CNFs achieved the highest Rc for NO catalytic oxidation at room temperature,the value is 61%.