Catalytic Preparation Of Carbon Nanomaterials From Soluble Starch And Application Research Of Supercapacitors

The preparation and application of carbon nanomaterials has always been an important research direction for researchers in the field of chemistry.With the increasingly severe environmental problems and the deepening of the national energy policy,the preparation of high-value carbon nanomaterials from renewable biomass carbon sources and the application of carbon nanomaterials in energy storage devices has become a hot issue urgently to be solved.In this paper,carbon nanotubes（CNTs）and hollow carbon nanospheres（HCNs）were prepared by Ni-Mo bimetallic catalyst with soluble starch as carbon source,which were respectively used as electrode materials for supercapacitor.The specific research content is as follows:Firstly,carbon nanotubes were synthesized by Ni-Mo/Al₂O₃ catalyst from soluble starch.The effects of different Ni and Mo content and reaction temperature on the morphology and yield of carbon nanotubes and the difference of electrochemical properties of electrode materials made from different carbon nanotubes were investigated.When the reaction temperature was 1000 ^oC,the amount of soluble starch was 10 g and the amount of catalyst was 1.5 g,the optimal catalyst ratio for the growth of carbon nanotubes was Ni-Mo-Al=11:0.1:1.A combination of Raman spectroscopy（Raman）,X-ray diffraction（XRD）,thermogravimetric analysis（TGA）and nitrogen isothermal adsorption analysis show that carbon nanotubes have the potential as electrode materials for supercapacitor.CNTs-11 showed maximum capacitance(210 F g^-1 at 2 m V s^-1),very small equivalent series resistance（0.75Ω）,and excellent cyclic stability（99%capacitance retention after 5000 cycles）in the 6 M KOH electrolyte.At the same time,with 1 M Na₂SO₄ solution as the electrolyte,CNTs-11 can provide 21.2 Wh kg^-1 energy density when the power density is 1728.2 W kg^-1,and the capacitance retention rate is 95%after 5000 cycles.Then,hollow carbon nanospheres were synthesis using MgO as catalyst base and soluble starch as carbon source.The effect of different Ni content and reaction temperature on the yield of hollow carbon nanospheres and the difference of electrochemical properties of electrode materials made from different hollow carbon nanospheres were investigated.When the reaction temperature was 1000 ^oC,the amount of soluble starch was 10 g and the amount of catalyst was 1.5g,the optimal catalyst ratio for the growth of hollow carbon nanospheres was Ni-Mo-Mg=2:0.06:1.A combination of Raman,XRD,TGA and nitrogen isothermal adsorption analysis shows that hollow carbon nanospheres have the potential as electrode materials for supercapacitor.HCNs-2 showed maximum capacitance(182 F g^-1 at 2 m V s^-1),small equivalent series resistance（0.99Ω）,and good cyclic stability（93%capacitance retention after5000 cycles）in the 6 M KOH electrolyte.At the same time,with 1 M Na₂SO₄ solution as the electrolyte,HCNs-2 can provide 16.7 Wh kg^-1 energy density when the power density is 1582.1W kg^-1,the capacitance retention rate is 88%after 5000 cycles.These results indicate that both carbon nanotubes and hollow carbon nanospheres can be used as electrode materials for supercapacitor.