Preparation And Application Of Biomass-based Nitrogen-carbon Materials

1)A novel activated carbon-based prepared from profusely available bio-mass material?rape straw?by hydrothermal carbonization-activation,activated carbon-based materials is employed for malachite green from aqueous solution.The study of the sorption kinetics indicates that the adsorption on malachite green by active carbon?AC?and nitrogen-doped carbon?L-NAC?,which following the pseudo-second-order model.The malachite green adsorption by AC and L-NAC showed three phase in the intraparticle diffusion model,which the internal transfer might be the rate-limiting step.The adsorption isotherms experimental date were analyzed by the Langmuir,Freundlich and Temkin models,and the equilibrium date was well described by the Langmuir isotherm models.The results showed that the adsorbents possessed excelent adsorption abilities to malachite green.The adsorption behaviors of adsorbents based on AC and L-NAC materials for malachite green from aqueous solutions were investigated in this paper.Adsorbents were characterized by X-ray diffraction?XRD?,scanning electron microscopy?SEM?,N₂ adsorption-desorption?BET?,X-ray photoelectron spectroscopy?XPS?.2)N-doping and high surface area are considered as most important properties for an ideal electrode material in high performance supercapacitors.Herein,we report a simple synthetic strategy to obtain a high surface area(2853.5 m² g^-1)and well developed micro/mesopores.The materials?NAC-3?were fabricated by carbonization of the walnut shell and nitrogen resources mixtures followed by KOH activation.The optimized material NAC-3 shows a high specific capacitance of 316.7 F g^-1 at 0.5 A g^-1 and a promising rate performance retaining 175.4 F g^-1at 10 A g^-1,delivering a high energy density is 10.5 W h kg^-1 at a power density of 225 W kg^-1at 0.5 A g^-1 and remained 7.2 W h kg^-1 at 4495.0 W kg^-1 at 10 A g^-1.Stable capacitance retention over 82%for 1000 cycles is also achieved at 1 A g^-1.The effect morphology,structure and electrochemical were studied by X-ray diffraction?XRD?,scanning electron microscopy?SEM?,N₂ adsorption-desorption,X-ray photoelectron spectroscopy?XPS?,elemental analyzer?EA?,roman spectra?RS?,and evaluated using cyclic voltammetry?CV?,galvanostatic charge-discharge?GCD?,and electrochemical impedance spectroscopy?EIS?.