| The objective of this paper is introducing a novel routing to synthesize carbon materials by chemical reactions. The novelties and specialties of the paper are as follow:1. CaC2 as the central reactant was used directly to synthesize carbon materials through the chemical reactions between CaC2 and chlorohydrocarbon or C2H2O4·2H2O; 2. Carbon materials which possess high graphitization degree were obtained at lower temperature of 224-250?, this is the lowest temperatures as far as I know (CaC2 and CCl4 or CHCl3 were as reactants); 3. High-purity and uniform-size carbon nanospheres (CNSs) were obtained at lower temperature of 65?, this is the lowest temperature as far as I know (CaC2 and C2H2O4·2H2O were as reactants); 4. The reaction conditions (temperature, pressure) have a lillte effect on the results of the products, while using different reaction materials, the results of the products display some difference.5. The synthesizing process and set-up of this method are simple; the central materials of CaC2 are very cheap and facile; the synthese conditions are mild with lower temperatures (65-300?) than those in previous methods; and the theory carbon yield (21%) and experiment carbon yield (8.0-14.4%) are high, which can dramatically reduce costs.1. The experimental apparatus used to synthesize carbon spheres (CSs) and CNSs have three parts, including a 120ml stainless steel pressure vessel, an electrical heating furnace and a temperature controller. The pressure vessel was heated by an electrical heating furnace, and the temperature was adjusted and controlled by a temperature controller. All the reactants were weighted and put in the reactor in molar ratios, then the reactor was heated to temperatures of 65-300?, black, soft and cotton-like substance of CSs, CNSs, graphite and amorphous carbon were obtained. Afterwards, the products were characterized by scanning electron microscope (SEM, JSM-6360 LV); energy dispersive X-ray spectrometer (EDS) attached to SEM; transmission electron microscope (TEM, Tecnai G2 20 St and FEI Tecnai G2 F20 field emission TEM); X-ray diffractometer (XRD, Rigaku D/Max2550VB+) and Raman spectrometer (Labram-010, He-Ne laser,632.832 nm excitation).2. The?Gf and?Hf of the chemical reactions are negative at 298K and 500K, the chemical reactions are favorable thermodynamically and are heart-releasing reactions; therefore, lower temperatures are favorable for the progress of the reactions and the formation of the products. From carbon tetrachloride (CCl4) to trichloromethane(CHCl3) and dichloromethane (CH2Cl2), decreasing a Cl atom and adding an H atom, the molar ratios of calcium carbide (CaC2) to chlorohydrocarbon decrease and the reaction temperatures decrease in sequence (250?,224?,210?); the yield increase in sequence (20%,40%,95%); the size decrease and the size distributions are more uniform in sequence (100-2000nm,200-500nm,100-200nm); the experimental carbon yield decrease in sequence (14.4%,12.2%,8.0%), the carbon content of the CSs and CNSs increase in sequence (86.1%,87.1%, 94.7%)(wt%); whereas the graphitization degree of the samples decrease in sequence (81.4%,78.7%,0.0%).3. When CaC2 and oxalic acid (C2H2O4·2H2O) were used as the reactants, the synthesized CNSs were with unform size (60-120nm), high purity (>95%), high carbon contents (98%) and high experimental carbon yield (4%). The CNS size and size distribution changed little, when reactant molar ratio and the processing temperature were altered. Lower processing temperature and a suitable reactant molar ratio are beneficial for the formation of CNSs. Moreover, the size and size distribution of CNSs are the least when reactant molar ratio is 3:1 at 65?, while the yield is the greatest. |
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