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物理化学学报  2019, Vol. 35 Issue (2): 208-214    DOI: 10.3866/PKU.WHXB201802121
论文     
CO2熔盐电化学转化碳材料的电化学特性
谷雨星,杨娟,汪的华*()
Electrochemical Features of Carbon Prepared by Molten Salt Electro-Reduction of CO2
Yuxing GU,Juan YANG,Dihua WANG*()
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摘要:

基于对熔融碳酸盐体系中电化学还原CO2所得碳材料(electrolytic-carbon,EC)的形貌、结构、组成的认识,以粉末微电极循环伏安法测试为基础,在稀溶液中对EC的本征电化学行为进行了考察,以揭示这类碳材料的界面电化学特性。实验发现,在典型条件(450 ℃、4.5 V槽压)下制备的电解碳(450 ℃-4.5 V-EC)的伏安行为有别于多壁碳纳米管、石墨烯、石墨、乙炔黑等常见碳材料,在负电位区表现出显著的“双电层充放电响应迟滞”现象。通过考察溶液pH值、电位扫描速率、阴阳离子种类对这一现象的影响,发现pH和电解液组成都不影响这一现象的出现;电解液浓度提高和低扫描速率时滞后现象减弱,表明迟滞充放电是这类碳材料的本征特性,与其表面含氧官能团及其对阳离子的特性吸附密切相关。实验进一步研究了不同电解条件下制备的EC所展现的电化学特性吸附及电容性质,发现随着熔盐温度的升高,EC对电解液中阳离子的特性吸附能力降低,而相同温度不同槽压下制备的EC特性吸附能力相近,表现出相似的电容特性,这与EC的含氧量和比表面积有关。电解碳所展现的独特电容特性对其潜在的应用或可提供有价值的线索和指导。

关键词: CO2转化碳材料熔盐粉末微电极电化学特性特性吸附    
Abstract:

The molten salt CO2 capture and electrochemical transformation (MSCC-ET) process is a potentially efficient method for CO2 utilization, which can convert CO2 into value-added carbon and oxygen with a current density of 100–1000 mA cm-2. The electrolytic carbon (EC) prepared through the MSCC-ET process is highly electrically conductive and forms flexible microstructures. These structures show excellent adsorption ability towards environmental pollutants and high energy storage capacity when used in supercapacitors. Although the morphology, structure, and application of EC prepared under different electrolysis conditions have been previously reported, their intrinsic electrochemical properties have not yet been elucidated. Powder microelectrodes (PMEs) are useful for studying the electrochemical kinetics of various powdery materials. In this study, we systematically investigated the electrochemical properties of ECs obtained using molten Li2CO3-Na2CO3-K2CO3 under different temperature and electrolysis voltage conditions by cyclic voltammetry (CV) with a carbon powder microelectrode in 10 mmol L-1 Na2SO4. The electrochemical behavior of the EC obtained at 450 ℃ and a cell voltage of 4.5 V (450 ℃-4.5 V-EC) differs significantly from that of other carbon materials, i.e., multi-walled carbon nanotubes, graphene, graphite, and acetylene black. In addition to a much larger charging-discharging capacity, unusual hysteresis of the charge/discharge current response of ECs in the negative potential region (-0.6 to -0.2 V vs SCE) was observed. This phenomenon was eliminated by annealing the material under Ar at 550 ℃, demonstrating that the unique electrochemical behavior of ECs is closely related to the oxygen-containing groups on its surface. Furthermore, CVs of EC-PME were compared in solutions with different pH, Na2SO4 concentrations, and other ions. The pH of the solution did not affect the CVs, excluding a redox mechanism involving the surface functional groups. Hysteresis was weakened by a certain degree at slower potential sweep speeds (< 10 mV s-1) or in higher concentrations of electrolyte (100 mmol L-1 Na2SO4). The onset potential for discharging was negatively shifted in electrolytes with a larger cation ((NH4)2SO4) and was unaffected by larger anions (Na2S2O8). This indicates that the hysteresis is more likely related to the specific adsorption of cations, caused by the unique surface properties of EC. It should be noted that the specific surface area and oxygen concentration of EC can be adjusted by the electrolysis temperature and cell voltage. Generally, the Brunauer–Emmett–Teller (BET) specific surface area and oxygen content decrease with increasing temperature and the BET-area increases with increasing cell voltage. The CVs of ECs prepared at different cell voltages were similar, but the adsorption capacity decreased for those prepared at higher temperatures (550 and 650 ℃). Interestingly, the specific capacitance of the ECs is much higher at negative potentials (-0.6 to 0 V vs. SCE) than that at positive potentials (0 to 0.6 V vs. SCE). Therefore, it is anticipated that a better capacitance performance can be achieved when the ECs are used as a negative electrode material in supercapacitors.

Key words: Electrolytic-carbon    Molten salts    Powder microelectrode    Electrochemical property    Specific adsorption
收稿日期: 2018-01-15 出版日期: 2018-02-12
中图分类号:  O646  
基金资助: 国家自然科学基金(21673162);国家自然科学基金(51325102);科技部国际科技合作专项(2015DFA90750)
通讯作者: 汪的华     E-mail: wangdh@whu.edu.cn
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引用本文:

谷雨星,杨娟,汪的华. CO2熔盐电化学转化碳材料的电化学特性[J]. 物理化学学报, 2019, 35(2): 208-214, 10.3866/PKU.WHXB201802121

Yuxing GU,Juan YANG,Dihua WANG. Electrochemical Features of Carbon Prepared by Molten Salt Electro-Reduction of CO2. Acta Phys. -Chim. Sin., 2019, 35(2): 208-214, 10.3866/PKU.WHXB201802121.

链接本文:

http://www.whxb.pku.edu.cn/CN/10.3866/PKU.WHXB201802121        http://www.whxb.pku.edu.cn/CN/Y2019/V35/I2/208

EC Specific surface area/(m2·g?1) Oxygen mass fraction/%
450 ℃-3.5 V 558.1 17.5
450 ℃-4.5 V 613.7 16.3
450 ℃-5.5 V 868.3 14.0
550 ℃-4.5 V 212.4 10.0
650 ℃-4.5 V 101.9 14.2
表1  不同EC的比表面积及氧含量
图1  粉末微电极填充碳粉前(a)、后(b)金相显微图,及微腔深度测量图(c),(d)
图2  粉末微电极及测试装置示意图
图3  不同碳材料CV测试对比
图4  550 ℃氩气气氛热处理12 h后450 ℃-4.5 V-EC的CV曲线
图5  450 ℃-4.5 V-EC在不同pH条件下(扫速:50 mV·s-1) (a)和10 mmol·L-1 Bu4NClO4-乙腈电解液中(扫描速率:100 mV·s-1) (b)的CV曲线
图6  450 ℃-4.5 V-EC在不同扫描速率(电解液:10 mmol·L-1 Na2SO4) (a)和扫描速率50 mV·s-1、100 mmol·L-1 Na2SO4电解液中(b)的CV曲线
图7  EC在不同极化状态下离子吸脱附示意图
图8  450 ℃-4.5 V-EC在10 mmol·L-1 (NH4)2SO4电解液(a)和10 mmol·L-1 Na2S2O8电解液(b)中的CV曲线
图9  不同熔盐温度下制备的EC的CV曲线(a);450 ℃不同槽压下制备的EC的CV曲线(b)
1 Bai X. F. ; Chen W. ; Wang B. Y. ; Feng G. H. ; Wei W. ; Jiao Z. ; Sun Y. H. Acta Phys. -Chim. Sin. 2017, 33, 2388.
doi: 10.3866/PKU.WHXB201706131
白晓芳; 陈为; 王白银; 冯光辉; 魏伟; 焦正; 孙予罕. 物理化学学报,, 2017, 33, 2388.
doi: 10.3866/PKU.WHXB201706131
2 Licht S. Adv. Mater. 2011, 23, 5592.
doi: 10.1002/adma.201103198
3 Yin H. Y. ; Mao X. H. ; Tang D. Y. ; Xiao W. ; Xing L. R. ; Zhu H. ; Wang D. H. ; Sadoway D. R. Energy Environ. Sci. 2013, 6, 1538.
doi: 10.1039/c3ee24132g
4 Tang D. Y. ; Yin H. Y. ; Mao X. H. ; Xiao W. ; Wang D. H. Electrochim. Acta 2013, 114, 567.
doi: 10.1016/j.electacta.2013.10.109
5 Kaplan B. ; Groult H. ; Barhoun A. ; Lantelme F. ; Nakajima T. ; Gupta V. ; Komaba S. ; Kumagai N. J. Electrochem. Soc. 2002, 149, D72.
doi: 10.1149/1.1464884
6 Ijije H. V. ; Lawrence R. C. ; Chen G. Z. RSC Adv. 2014, 4, 35808.
doi: 10.1039/c4ra04629c
7 Ge J. B. ; Wang S. ; Hu L. W. ; Zhu J. ; Jiao S. Q. Carbon 2016, 98, 649.
doi: 10.1016/j.carbon.2015.11.065
8 Ijije H. V. ; Sun C. ; Chen G. Z. Carbon 2014, 73, 163.
doi: 10.1016/j.carbon.2014.02.052
9 Tang J. ; Deng B. ; Xu F. ; Xiao W. ; Wang D. J. Power Sources 2017, 341, 419.
doi: 10.1016/j.jpowsour.2016.12.037
10 Ge J. B. ; Hu L. W. ; Wang W. ; Jiao H. D. ; Jiao S. Q. ChemElectroChem 2015, 2, 224.
doi: 10.1002/celc.201402297
11 Groult H. ; Kaplan B. ; Lantelme F. ; Komaba S. ; Kumagai N. ; Yashiro H. ; Nakajima T. ; Simon B. ; Barhoun A. Solid State Ionics 2006, 177, 869.
doi: 10.1016/j.ssi.2006.01.051
12 Mao X. H. ; Yan Z. P. ; Sheng T. ; Gao M. X. ; Zhu H. ; Xiao W. ; Wang D. H. Carbon 2017, 111, 162.
doi: 10.1016/j.carbon.2016.09.035
13 Novoselova I. A. ; Oliinyk N. F. ; Volkov S. V. ; Konchits A. A. ; Yanchuk I. B. ; Yefanov V. S. ; Kolesnik S. P. ; Karpets M. V. Phys. E: Low-Dimen. Syst. Nanostruct. 2008, 40, 2231.
doi: 10.1016/j.physe.2007.10.069
14 Song Q. ; Xu Q. ; Wang Y. ; Shang X. ; Li Z. Thin Solid Films 2012, 520, 6856.
doi: 10.1016/j.tsf.2012.07.056
15 Ren J. ; Li F. F. ; Lau J. ; Gonzalez-Urbina L. ; Licht S. Nano Lett. 2015, 15, 6142.
doi: 10.1021/acs.nanolett.5b02427
16 Deng B. W. ; Mao X. H. ; Xiao W. ; Wang D. H. J. Mater. Chem. A 2017, 5, 12822.
doi: 10.1039/c7ta03606j
17 Deng B. W. ; Tang J. J. ; Gao M. X. ; Mao X. H. ; Zhu H. ; Xiao W. ; Wang D. H. Electrochim. Acta 2018, 259, 975.
doi: 10.1016/j.electacta.2017.11.025
18 Cha C. S. ; Li C. M. ; Yang H. X. ; Liu P. F. J. Electroanal. Chem. 1994, 368, 47.
doi: 10.1016/0022-0728(93)03016-I
19 Zhao Y. D. ; Zhang W. D. ; Chen H. ; Luo Q. M. Anal. Sci. 2002, 18, 939.
doi: 10.2116/analsci.18.939
20 Zhao Y. D. ; Zhang W. D. ; Chen H. ; Luo Q. M. Sens. Actuators B 2003, 92, 279.
doi: 10.1016/s0925-4005(03)00312-5
21 Luo J. W. ; Zhang M. ; Pang D. W. Sens. Actuators B 2005, 106, 358.
doi: 10.1016/j.snb.2004.08.020
22 Zeng R. H. ; Li W. S. ; Lu D. S. ; Huang Q. M. J. Power Sources 2007, 174, 592.
doi: 10.1016/j.jpowsour.2007.06.120
23 Vivier V. ; Cachet Vivier C. ; Cha C. S. ; Nedelec J. Y. ; Yu L. T. Electrochem. Commun. 2000, 2, 180.
doi: 10.1016/S1388-2481(00)00004-7
24 Serghini Idrissi M. ; Bernard M. C. ; Harrif F. Z. ; Joiret S. ; Rahmouni K. ; Srhiri A. ; Takenouti H. ; Vivier V. ; Ziani M. Electrochim. Acta 2005, 50, 4699.
doi: 10.1016/j.electacta.2005.01.050
25 Rabbow T. J. ; Trampert M. ; Pokorny P. ; Binder P. ; Whitehead A. H. Electrochim. Acta 2015, 173, 24.
doi: 10.1016/j.electacta.2015.05.058
26 Luo H. ; Shi Z. ; Li N. ; Gu Z. ; Zhuang Q. Anal. Chem. 2001, 73, 915.
doi: 10.1021/ac000967l
27 Rabbow T. J. ; Whitehead A. H. Carbon 2017, 111, 782.
doi: 10.1016/j.carbon.2016.10.064
28 Jorgensen T. C. ; Weatherley L. R. Water Res. 2003, 37, 1723.
doi: 10.1016/s0043-1354(02)00571-7
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