槽电压对CaCl_(2)基熔盐电化学转化CO_(2)制备碳材料的影响

Effect of cell voltage on electrochemical conversion of CO_(2)to carbon materials in CaCl_(2)based molten salt

以氯化钙基熔盐为电解质,将CO_(2)电化学转化为碳材料,考察了槽电压、熔盐组成对碳材料制备的影响。借助X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDS)、激光显微拉曼光谱(Raman)等分析手段对碳材料的物相、形貌结构、元素分布、石墨化程度等特性进行表征。结果表明:在800℃CaCl_(2)-5%(质量分数)CaO熔盐中,槽电压为1.9 V的电解产物形貌为薄片状,碳质量分数为98.24%,随着槽电压升高,产物倾向于形成棒状结构且棒状产物长度增加;采用熔点更低的CaCl_(2)-NaCl-KCl-5%(质量分数)CaO三元熔盐进行电解,降低了制备碳材料的能耗,减轻了阳极的腐蚀,所得产物主要形貌为纳米管状、颗粒状和球状。槽电压对产物形貌的影响显著;高槽电压使得反应过程电流更大,电化学反应动力学加快,所得碳材料的石墨化程度更低。

Using calcium chloride-based molten salt as electrolyte,CO_(2)was electrochemically converted into carbon materi⁃als.The effects of electrolysis voltage and molten salt composition on the preparation of carbon materials were investigated.The phase,morphology,element distribution,graphitization degree and other characteristics of carbon materials were char⁃acterized by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray energy dispersive spectroscopy(EDS),laser micro Raman spectroscopy(Raman)and other analysis methods.The results showed that in the CaCl_(2)-5%CaO molten salt at 800℃,the electrolytic produccts with the cell voltage of 1.9 V had thin morphology and the carbon con⁃tent was 98.24%.With the increase of voltage,the products were tended to form rod like structures and the length of rod like products was increased.The ternary molten salt CaCl_(2)-NaCl-KCl-5%CaO with a lower melting point was used for electroly⁃sis,which reduced the energy consumption for preparing carbon materials and reduced the corrosion of anodes.The main morphologies of the products obtained were nanotube,granular and spherical.The effect of electrolysis voltage on the prod⁃uct appearance was significant.The high cell voltage could increase the current of the reaction process,accelerate the elec⁃trochemical reaction kinetics,and lower the degree of graphitization of carbon materials.