Indirect electrochemical reduction of carbon dioxide to carbon nanopowders in molten alkali carbonates: Process variables and product properties
Indirect electrochemical reduction of carbon dioxide to carbon nanopowders in molten alkali carbonates: Process variables and product properties
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DOI：
10.1016/j.carbon.2014.02.052
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发表时间：
2014-07-01
期刊：
影响因子：
10.9
通讯作者：
Chen, George Z.
中科院分区：
文献类型：
--
作者：
Ijije, Happiness V.;Sun, Chenggong;Chen, George Z.
在3.0 ~ 5.0 V、540 ~ 700℃的CO2或N-2与CO2混合气氛下，在Li2CO3与K2CO3的熔融液（摩尔比：62:38）中电解碳沉积在低碳钢阴极上。在三电极电池中，用循环伏安法研究铂工作电极的还原和沉积过程。双电极电池有助于将电解变量（如温度和电压）与沉积速率、电流效率和沉积碳粉的性质联系起来。在研究中获得了高电流效率（>90%）和沉积速率(>0.11 g cm（-2) h(-1)）。用HCl溶液（2.3-7.8 mol / l(-1)）洗涤后，对电解沉积物进行元素分析，表明碳是主要元素（75-95 wt.%），氧（5-10 wt.%）和少量与电解槽材料有关的其他元素。根据电解和酸洗条件，热重法检测到相当低的起始燃烧温度（310-430℃）。在不同的工艺条件下沉积的碳样品在电子显微镜下显示出非晶态和各种纳米结构（片状、环状和准球形）。在5.0 V和540℃下沉积的碳的比表面积高达585 m(2) g（-1）。对能源消耗的分析提出了几种提高效率的方法，以便从二氧化碳中电解碳将具有商业吸引力。(C) 2014 Elsevier Ltd.版权所有。
Carbon was deposited on a mild steel cathode during electrolysis in the molten mixture of Li2CO3 and K2CO3 (mole ratio: 62:38) under CO2 or mixed N-2 and CO2 atmospheres at 3.0-5.0 V and 540-700 degrees C. In a three-electrode cell, cyclic voltammetry was applied on a platinum working electrode to study the reduction and deposition processes. A two-electrode cell helped correlate electrolysis variables, e.g. temperature and voltage, with the deposition rate, current efficiency, and properties of the deposited carbon powders. High current efficiency (>90%) and deposition rate (>0.11 g cm(-2) h(-1)) were achieved in the study. Elemental analysis of the electro-deposits, following washing with HCl solutions (2.3-7.8 molL(-1)), showed carbon as the dominant element (75-95 wt.%) plus oxygen (5-10 wt.%) and small amounts of other elements related to materials of the electrolytic cell. Thermogravimetry detected fairly low onset combustion temperatures (310-430 degrees C), depending on the electrolysis and acid washing conditions. Amorphous and various nanostructures (sheet, rings and quasi-spheres) were revealed by electron microscopy in carbon samples deposited under different process conditions. The specific surface area of the carbon deposited at 5.0 V and 540 degrees C was as high as 585 m(2) g(-1). An analysis of the energy consumption suggests several ways for efficiency improvement so that the electrolytic carbon from CO2 will become commercially attractive. (C) 2014 Elsevier Ltd. All rights reserved.