熔盐体系组成对二氧化碳电化学合成新型碳材料形貌影响

doi:10.16085/j.issn.1000-6613.2018-2309

摘要/Abstract

摘要：

以碳酸盐为电解质，以铁、镍、镍铬合金等廉价金属材料为电极，研究构建了高温熔盐电解池，将CO₂一步法转化为新型碳材料，并考察了熔盐组成及配比、电解温度、电流密度、电极材料等实验条件对碳材料形貌结构的影响。采用X射线能谱分析仪（EDS）、扫描电镜（SEM）、透射电镜（TEM）、比表面积测试仪（BET）、X射线衍射仪（XRD）及拉曼光谱仪（Raman）等手段对碳材料的元素组成、形貌结构、比表面积、结晶度、有序度等特性进行表征分析。研究结果表明，450～600℃温度范围内，电解多元混合熔盐体系主要生成无定形碳；同时，电解温度、电流密度、电解质组成及配比等对碳产物的比表面积具有明显影响；通过改变电解质体系，辅以调控电流密度及电解温度等实验参数，可实现碳纳米管、碳球及蜂窝状多孔碳等特定形貌碳材料的可控合成，其中碳纳米管的石墨化程度较高，且由碳原子组成的层状六方石墨晶体排列规则有序。

关键词: 二氧化碳, 熔融碳酸盐, 碳纳米管, 碳球, 蜂窝状多孔碳

Abstract:

This research aims to provide a feasible route to achieve the CO₂ reduction and utilization. With carbonate used as electrolyte, and inexpensive Fe, Ni and Ni-Cr as electrodes, a molten carbonate electrolyzer is established and CO₂ is facilely converted into novel carbon materials. Moreover, the impact of the electrolyte conformation, electrolytic temperature, current density and electrode material on the morphology of the synthesized carbon products are studied. Electron dispersive spectroscope (EDS), scanning electron microscope (SEM), transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET) analyzer, X-ray diffractometer (XRD) and Raman spectroscope (Raman) are employed to characterize the element composition, morphology & structure, BET surface area, crystallinity and graphite crystal regularity of the prepared carbon materials. The results demonstrate that hybrid carbonates electrolysis under 450℃ to 600℃ prefers amorphous carbons generation. BET surface area significantly depends on the applied temperature, current density and electrolyte composition, where lower temperature and elevated current density provide carbon products with a higher BET surface area. Moreover, the ambient CO₂ could be controllably transformed into carbon materials with desirable microstructures such as carbon nanotubes, carbon spheres and honeycomb-like carbon through regulating the electrolytic parameters of electrolyte conformation, temperature, electrode materials, etc. Of all the synthetic carbon materials, carbon nanotubes exhibit the highest graphitization and the most ordered hexagonal graphite crystals. This work demonstrates a feasible route for the direct CO₂ conversion and facile synthesis of nanostructured carbons, fitting well with the sustainable concept.

Key words: carbon dioxide, molten carbonates, carbon nanotubes, carbon spheres, honeycomb-like carbon

中图分类号:

O646

李志达,李金莲,吴红军. 熔盐体系组成对二氧化碳电化学合成新型碳材料形貌影响[J]. 化工进展, 2019, 38(9): 4174-4182.

Zhida LI,Jinlian LI,Hongjun WU. Impact of molten salts conformation on the morphology of the electrochemically synthesized carbon materials[J]. Chemical Industry and Engineering Progress, 2019, 38(9): 4174-4182.

图/表 9

参考文献 28

1	JOHNSSON F . Perspectives on CO₂ capture and storage[J]. Greenhouse Gases Science & Technology, 2011, 1(2): 119-133.
2	PIRES J C M , MARTINS F G , ALVIM-FERRAZ M C M , et al . Recent developments on carbon capture and storage: an overview[J]. Chemical Engineering Research & Design, 2011, 89(9): 1446-1460.
3	姚蔓莉, 董艳艳, 谢菁, 等 . 聚乙烯亚胺修饰的氧化硅纳米管基吸附剂的制备及其CO₂吸附应用[J]. 物理化学学报, 2014, 30(4): 789-796.
	YAO M L , DONG Y Y , XIE J , et al . Preparation of polyethylenimine-functionalized silica nanotubes and their application for CO₂ adsorption[J]. Acta Physico-Chimica Sinica, 2014, 30(4): 789-796.
4	KOOHESTANIAN E , SADEGHI J , MOHEBBI-KALHORI D , et al . A novel process for CO₂ capture from the flue gases to produce urea and ammonia[J]. Energy, 2018, 144: 279-285.
5	IIJIMA T , YAMAGUCHI T . K₂CO₃-catalyzed direct synthesis of salicylic acid from phenol and supercritical CO₂ [J]. Applied Catalysis A: General, 2008, 345(1): 12-17.
6	SUN B C , WANG X M , CHEN J M , et al . Synthesis of nano-CaCO₃ by simultaneous absorption of CO₂ and NH₃ into CaCl₂ solution in a rotating packed bed[J]. Chemical Engineering Journal, 2011, 168(2): 731-736.
7	LIM M, HAN G C , AHN J W, et al . Environmental remediation and conversion of carbon dioxide (CO₂) into useful green products by accelerated carbonation technology[J]. International Journal of Environmental Research and Public Health, 2010, 7(1): 203-228.
8	DELIMARSKII Y K , GORODYSKII A V , GRISHCHENKO V F . Cathode liberation of carbon from molten carbonates[J]. Doklady Akademii Nauk, 1964,156: 650-651.
9	INGRAM M D , BARON B , JANZ G J . The electrolytic deposition of carbon from fused carbonates[J]. Electrochimica Acta, 1966, 11(11):1629-1639.
10	YIN H Y , MAO X H , TANG D Y , et al . Capture and electrochemical conversion of CO₂ to value-added carbon and oxygen by molten salt electrolysis[J]. Energy & Environmental Science, 2013, 6(5): 1538-1545.
11	IJIJE H V , SUN C G , CHEN G Z . Indirect electrochemical reduction of carbon dioxide to carbon nanopowders in molten alkali carbonates: process variables and product properties[J]. Carbon, 2014, 73(7): 163-174.
12	MASSOT L , CHAMELOT P , BOUYER F , et al . Studies of carbon nucleation phenomena in molten alkaline fluoride media[J]. Electrochimica Acta, 2003, 48(5): 465-471.
13	KAWAMURA H , ITO Y . Electrodeposition of cohesive carbon films on aluminum in a LiCl-KCl-K₂CO₃ melt[J]. Journal of Applied Electrochemistry, 2000, 30(5): 571-574.
14	SONG Q S , XU Q , WANG Y , et al . Electrochemical deposition of carbon films on titanium in molten LiCl-KCl-K₂CO₃ [J]. Thin Solid Films, 2012, 520(23): 6856-6863.
15	IJIJE H V , LAWRENCE, R C, SIAMBUN N J , et al . Electro-deposition and re-oxidation of carbon in carbonate-containing molten salts[J]. Faraday Discussions, 2014, 172: 105-116.
16	REN J W , LI F F , LAU J, et al . One-pot synthesis of carbon nanofibers from CO₂ [J]. Nano Letters, 2015, 15(9): 6142-6148.
17	DOUGLAS A , MURALIDHARAN N , CARTER R , et al . Sustainable capture and conversion of carbon dioxide into valuable multiwalled carbon nanotubes using metal scrap materials[J]. ACS Sustainable Chemistry & Engineering, 2017, 5(8): 7104-7110.
18	WU H J , LI Z D , JI D Q , et al . Effect of molten carbonate composition on the generation of carbon material[J]. RSC Advances, 2017, 7(14): 8467-8473.
19	LI Z D , YUAN D D , WU H J , et al . A novel route to synthesize carbon spheres and carbon nanotubes from carbon dioxide in a molten carbonate electrolyzer[J]. Inorganic Chemistry Frontiers, 2018, 5(1): 208-216.
20	吴红军, 李志达, 谷笛, 等 . 电化学转化二氧化碳制备碳纳米材料及表征[J]. 东北石油大学学报, 2016, 40(2): 85-89.
	WU H J , LI Z D , GU D , et al . Preparation and characterization of carbon nano-materials obtained from electrochemical conversion of CO₂ [J]. Journal of Northeast Petroleum University, 2016, 40(2): 85-89.
21	TANG D Y , YIN H Y , MAO X H , et al . Effects of applied voltage and temperature on the electrochemical production of carbon powders from CO₂ in molten salt with an inert anode[J]. Electrochimica Acta, 2013, 114: 567-573.
22	IJIJE H V , LAWRENCE R C , CHEN G Z . Carbon electrodeposition in molten salts: electrode reactions and applications[J]. RSC Advances, 2014, 4(67): 35808-35817.
23	DENG B W , TANG J J , MAO X H , et al . Kinetic and thermodynamic characterization of enhanced carbon dioxide absorption process with lithium oxide-containing ternary molten carbonate[J]. Environmental Science & Technology, 2016, 50(19): 10588-10595.
24	IJIJE H V , CHEN G Z . Electrochemical manufacturing of nanocarbons from carbon dioxide in molten alkali metal carbonate salts: roles of alkali metal cations[J]. Advances in Manufacturing, 2016, 4(1): 23-32.
25	LICHT S , WU H J , HETTIGE C , et al . STEP cement: solar thermal electrochemical production of CaO without CO₂ emission[J]. Chemical Communications, 2012, 48(48): 6019-6021.
26	KHANG D Y , XIAO J L , KOCABAS C , et al . Molecular scale buckling mechanics in individual aligned single-wall carbon nanotubes on elastomeric substrates[J]. Nano Letters, 2008, 8(1): 124-130.
27	LICHT S , DOUGLAS A , REN J W , et al . Carbon nanotubes produced from ambient carbon dioxide for environmentally sustainable lithium-ion and sodium-ion battery anodes[J]. ACS Central Science, 2016, 2(3): 162-168.
28	WU H J , LI Z D , JI D Q , et al . One-pot synthesis of nanostructured carbon materials from carbon dioxide via electrolysis in molten carbonate salts[J]. Carbon, 2016, 106: 208-217.

T/K	碳酸盐	E _C/V	E _CO/V	E _M/V
400	Li₂CO₃	-2.26	-2.94	-3.67
	Na₂CO₃	-3.04	-3.97	-3.24
	K₂CO₃	-3.61	-4.73	-3.32
800	Li₂CO₃	-1.79	-2.12	-3.07
	Na₂CO₃	-2.60	-3.21	-2.65
	K₂CO₃	-3.13	-3.91	-2.70
1200	Li₂CO₃	-1.45	-1.49	-2.56
	Na₂CO₃	-2.22	-2.52	-2.09
	K₂CO₃	-2.68	-3.13	-2.01

T/K	碳酸盐	E _C/V	E _CO/V	E _M/V
400	Li₂CO₃	-2.26	-2.94	-3.67
	Na₂CO₃	-3.04	-3.97	-3.24
	K₂CO₃	-3.61	-4.73	-3.32
800	Li₂CO₃	-1.79	-2.12	-3.07
	Na₂CO₃	-2.60	-3.21	-2.65
	K₂CO₃	-3.13	-3.91	-2.70
1200	Li₂CO₃	-1.45	-1.49	-2.56
	Na₂CO₃	-2.22	-2.52	-2.09
	K₂CO₃	-2.68	-3.13	-2.01

电解质	温度/℃	电流密度/mA·cm^-2	比表面积/m²·g^-1
Li-Na-K（质量分数33.3%∶33.3%∶33.3%）	450	100	440
	500	100	267
	550	100	194
	600	50	34.5
		100	46.5
		200	69.1
Li-Na-K（质量分数61%∶22%∶17%）	600	100	25.7
Li-Na（质量分数50%∶50%）	600	100	44.9
Li-K（质量分数50%∶50%）	600	100	19.5

电解质	温度/℃	电流密度/mA·cm^-2	比表面积/m²·g^-1
Li-Na-K（质量分数33.3%∶33.3%∶33.3%）	450	100	440
	500	100	267
	550	100	194
	600	50	34.5
		100	46.5
		200	69.1
Li-Na-K（质量分数61%∶22%∶17%）	600	100	25.7
Li-Na（质量分数50%∶50%）	600	100	44.9
Li-K（质量分数50%∶50%）	600	100	19.5

[1]	杨寒月, 孔令真, 陈家庆, 孙欢, 宋家恺, 王思诚, 孔标. 微气泡型下向流管式气液接触器脱碳性能[J]. 化工进展, 2023, 42(S1): 197-204.
[2]	王胜岩, 邓帅, 赵睿恺. 变电吸附二氧化碳捕集技术研究进展[J]. 化工进展, 2023, 42(S1): 233-245.
[3]	时永兴, 林刚, 孙晓航, 蒋韦庚, 乔大伟, 颜彬航. 二氧化碳加氢制甲醇过程中铜基催化剂活性位点研究进展[J]. 化工进展, 2023, 42(S1): 287-298.
[4]	郑谦, 官修帅, 靳山彪, 张长明, 张小超. 铈锆固溶体Ce_0.25Zr_0.75O₂光热协同催化CO₂与甲醇合成DMC[J]. 化工进展, 2023, 42(S1): 319-327.
[5]	戴欢涛, 曹苓玉, 游新秀, 徐浩亮, 汪涛, 项玮, 张学杨. 木质素浸渍柚子皮生物炭吸附CO₂特性[J]. 化工进展, 2023, 42(S1): 356-363.
[6]	孙玉玉, 蔡鑫磊, 汤吉海, 黄晶晶, 黄益平, 刘杰. 反应精馏合成甲基丙烯酸甲酯工艺优化及节能[J]. 化工进展, 2023, 42(S1): 56-63.
[7]	王耀刚, 韩子姗, 高嘉辰, 王新宇, 李思琪, 杨全红, 翁哲. 铜基催化剂电还原二氧化碳选择性的调控策略[J]. 化工进展, 2023, 42(8): 4043-4057.
[8]	刘毅, 房强, 钟达忠, 赵强, 李晋平. Ag/Cu耦合催化剂的Cu晶面调控用于电催化二氧化碳还原[J]. 化工进展, 2023, 42(8): 4136-4142.
[9]	黄玉飞, 李子怡, 黄杨强, 金波, 罗潇, 梁志武. 光催化CO₂和CH₄重整催化剂研究进展[J]. 化工进展, 2023, 42(8): 4247-4263.
[10]	娄宝辉, 吴贤豪, 张驰, 陈臻, 冯向东. 纳米流体用于二氧化碳吸收分离研究进展[J]. 化工进展, 2023, 42(7): 3802-3815.
[11]	白亚迪, 邓帅, 赵睿恺, 赵力, 杨英霞. 变温吸附碳捕集机组标准化测试方案探讨及性能实验[J]. 化工进展, 2023, 42(7): 3834-3846.
[12]	龚鹏程, 严群, 陈锦富, 温俊宇, 苏晓洁. 铁酸钴复合碳纳米管活化过硫酸盐降解铬黑T的性能及机理[J]. 化工进展, 2023, 42(7): 3572-3581.
[13]	许春树, 姚庆达, 梁永贤, 周华龙. 氧化石墨烯/碳纳米管对几种典型高分子材料的性能影响[J]. 化工进展, 2023, 42(6): 3012-3028.
[14]	吕超, 张习文, 金理健, 杨林军. 新型两相吸收剂-离子液体系统高效捕获CO₂[J]. 化工进展, 2023, 42(6): 3226-3232.
[15]	顾诗亚, 董亚超, 刘琳琳, 张磊, 庄钰, 都健. 考虑中间节点的碳捕集管路系统设计与优化[J]. 化工进展, 2023, 42(6): 2799-2808.