石墨烯晶种法制备有序针状焦及电化学性研究

doi:10.15541/jim20130666

摘要/Abstract

摘要：

实验以石墨烯(Graphene, GE)为晶种, 精制煤沥青为原料, 通过程序控温, 对如何制备高含量的各向异性中间相条件进行了优化, 并将其用于制备半焦和针状焦研究。中间相和半焦的组织结构采用偏光显微镜进行了观察和分析, 针状焦用X射线衍射仪(XRD)和扫描电子显微镜(SEM)进行了观察, 并通过电化学工作站对半焦进行了电化学性质分析, 用循环伏安法对石墨微晶结构的有序性进行了分析。结果表明: 石墨烯的加入, 明显促进了中间相小球的形成, 显著提高了所制针状焦结构的有序性和电子的传输能力。其中, 当石墨烯加入量为原料的0.2wt%时, 得到的中间相小球数量最多且大小均匀, 半焦结构的纤维流域状结构成为其主要的显微组织。在相同的情况下, 同未加石墨烯相比较, 石墨烯的存在使制备的针状焦石墨化度提高了200%; 电荷迁移电阻减少65.3%。

关键词: 煤沥青, 石墨稀, 中间相, 半焦, 针状焦

Abstract:

Anisotropic mesophase pitch of the highest content were produced by using graphene (GE) as structural directing agent, and refined coal tar pitch as the raw material, and which was applied to prepare semi-coke and needle coke thereafter with the utilization of temperature controlling program. The textures of mesophase pitch and semi-coke were investigated by polarizing microscope, and the structure and morphology of needle coke were analyzed by X-ray diffraction analyzer and scanning electronic microscope, respectively. Its electrochemical properties were observed by electrochemical workstation and the microcrystallite structure was analyzed by cyclic voltammetry. The results showed that addition of graphene obviously accelerated the formation of meso-sphere and enhanced structural orientation of needle coke and the electric transporting capability. Especially, nearly the same size and the largest number of meso-sphere in the pitch were obtained when the mass percentage of graphene in feedstock reached 0.2wt%; and lots of fibrous texture in semi-coke can be observed. At the same conditions, the existence of graphene made the degree of graphitization of needle coke increase by 200% and the charge transfer resistance decrease by 65.3%, as comparing with that without graphene.

Key words: coal pitch, graphene, mesophase, semi-coke, needle coke

中图分类号:

TQ532
TQ522

解小玲, 曹青, 郭良辰, 钟存贵. 石墨烯晶种法制备有序针状焦及电化学性研究[J]. 无机材料学报, 2014, 29(9): 979-984.

XIE Xiao-Ling, CAO Qing, GUO Liang-Chen, ZHONG Cun-Gui. Preparation and Electrochemical Properties of Ordered Needle Coke with Graphene as an Inoculating Seed[J]. Journal of Inorganic Materials, 2014, 29(9): 979-984.

图/表 10

表1 中温沥青(CTP)和精制煤沥青(FCTP)的元素分析

Table 1 Elemental analyses of coal tar pitch (CTP) and refined coal tar pitch (FCTP)

Sample	Elemental analyses/wt%					H/C	QI (I)
Sample	C	H	O	N	S	H/C	QI (I)
CTP	93.00	4.53	0.73	0.94	0.83	0.58	5.12
FCTP	73.61	5.63	19.83	0.80	0.13	1.12	0.01

表2 石墨烯主要性质

Table 2 Main characteristics of graphene

Thickness/nm	Diameter/nm	Layers	Density/(g•m^-3)	Specific area/ (m²•g^-1)	C / wt%	O / wt%
0.34-3.4	30-50	<10	0.07	178	97	3

图1 制备中间相过程中控制的温度路线图

Fig. 1 Parameters of controlling temperature used in the meso-phase preparation process

图2 不同石墨烯含量所得中间相煤沥青的偏光显微照片

Fig. 2 Polarized micrographs of the mesophase produced from FCTP-GE (a) Without GE; (b) 0.1wt% GE; (c) 0.15wt% GE; (d) 0.2wt% GE; (e) 0.3wt% GE

图3 不同石墨烯含量所得半焦的偏光显微照片

Fig. 3 Polarized micrographs of the semi-coke with different contents of graphene (a) Without GE; (b) 0.1wt% GE; (c) 0.15wt%zw GE; (d) 0.2wt% GE; (e) 0.3wt% GE

图4 不同石墨烯含量所得针状焦的XRD图谱

Fig. 4 XRD patterns of the needle cokes with different contents of graphene (a) Without GE; (b) 0.1wt% GE; (c) 0.15wt% GE; (d) 0.2wt% GE; (e) 0.3wt% GE

Table 3 Structural parameters of needle cokes

Graphene/wt%	2θ/(°)	d₀₀₂/nm	Β/nm	L_c/nm	G/ %
0	25.606	3.476	0.518	0.287	/
0.10	26.109	3.4102	0.513	0.319	34.65
0.15	26.195	3.399	0.487	0.345	47.67
0.20	27.269	3.2676	0.287	1.073	200.46
0.30	26.943	3.3065	0.477	0.491	155.23

图5 不同石墨烯含量所得针状焦的SEM照片

Fig. 5 SEM images of the needle coke obtained from FCTP with different contents of graphene (a) Without GE; (b) 0.1wt% GE; (c) 0.15wt% GE; (d) 0.2wt% GE; (e) 0.3wt% GE

图6 不同石墨烯含量所得针状焦的循环伏安图

Fig. 6 Cyclic voltammograms of the needle coke with different contents of graphene (a) Without GE; (b) 0.1wt% GE; (c) 0.15wt% GE; (d) 0.2wt% GE; (e) 0.3wt% GE

图7 不同石墨烯含量所得针状焦的交流阻抗图

Fig. 7 EIS of the needle coke with different contents of graphene (a) Without GE; (b) 0.1wt% GE; (c) 0.15wt% GE; (d) 0.2wt% GE; (e) 0.3wt% GE

参考文献 19

[1]	KAWANO Y, FUKUDA T, KAWARADA T, et al. Suppression of puffing during the graphitization of pitch needle coke by boric acid. Carbon, 1999, 37(4): 555-560.
[2]	PRADA V, GRANDA M, BERMEJO J, et al. Preparation of novel pitches by tar air-blowing. Carbon, 1999, 37(1): 97-106.
[3]	PARK C W, YOON S H, OH S M. An EVS (electrochemical voltage spectroscopy) study for the comparison of graphitization behaviors of two petroleum needle cokes. Carbon, 2000, 38(9): 1261-1269.
[4]	LU C L, XU S P, GAN Y X. Effect of pre-carbonization of petroleum cokes on chemical activation process with KOH. Carbon, 2005, 43(11): 2295-2301.
[5]	YANG Y J, LIN Q L, HUANG Y Q, et al. Efficient preparation of mesocarbon microbeads by pyrolysis of coal-tar pitch in the presence of rosin. J. Anal. Appl. Pyrol., 2011, 91(2): 310-315.
[6]	LIN Q L, TANG H Y, LI C H, et al. Carbonization behavior of coal-tar pitch modified with lignin/silica hybrid and optical texture of resultant semi-cokes. J. Anal. Appl. Pyro., 2011, 90(1): 1-6.
[7]	CHENG X L, ZHA Q F, ZHONG J T, et al. Needle coke formation derived from co-carbonization of ethylene tar pitch and polystyrene. Fuel, 2009, 88(11): 2188-2192.
[8]	QIAO W M, YOON S H, MOCHIDA I. KOH activation of needle coke to develop activated carbons for high-performance EDLC. Energy Fuel, 2006, 20(4): 1680-1684.
[9]	NOVOSELOV K S, GEIM A K, MOROZOV S V, et al. Electric field effect in atomically thin carbon films. Science, 2004, 306(5696): 666-669.
[10]	NAM J A, NAHAIN A A, KIM S M, et al. Successful stabilization of functionalized hybrid graphene for high-performance antimicrobial activity. Acta Biomaterialia, 2013, 9(8): 7996-8003.
[11]	WANG C Y, MALLELA J, GARAPATI U S, et al. A chitosan-modified graphene nanogel for noninvasive controlled drug release. Nanomedicine:Nanotechnology, Biology, and Medicine, 2013, 9(7): 903-911.
[12]	BOLOTIN K I, SIKES K, JIANG Z, et al. Ultrahigh electron mobility in suspended grapheme. Solid State Commun., 2008, 146(9/10): 351-355.
[13]	MOROZOV S V, NOVOSELOV K S, KATSNELSON M I, et al. Giant intrinsic carrier mobilities in graphene and its bilayer. Phys. Rev. Lett. , 2008, 100(1): 016602-1-4.
[14]	ZIEGLER K. Minimal conductivity of graphene nonuniversal values from the Kubo formula. Phys. Rev. B, 2007, 75(23): 233407-1-4.
[15]	NAIR R, BLAKE P, GRIGORENKO A, et al. Fine structure constant defines visual transparency of graphene. Science, 2008, 320(5881): 1308.
[16]	CAO Q, XIE X L, LI J P, et al. A novel method for removing quinoline insolubles and ash in coal tar pitch using electrostatic fields. Fuel, 2012, 96(1): 314-318.
[17]	何曼君,张红东. 高分子物理. 上海: 复旦大学出版社, 2007: 38-51.
[18]	ZHU YANWU, MURALI SHANTHI, STOLLER MERYL D, et al. Carbon-based supercapacitors produced by activation of grapheme. Science, 2011, 332(24): 1537-1541.
[19]	ZHAO Y, LI P, WANG X B. Influence of initial biofilm growth on electrochemical behavior in dual-chambered mediator microbial fuel cell. Journal of Fuel Chemistry and Technology, 2012, 40(8): 967-972.