WO2017012281A1 - 一种等离子化学气相合成法制备纳米石墨烯粉体的方法 - Google Patents
一种等离子化学气相合成法制备纳米石墨烯粉体的方法 Download PDFInfo
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- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
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- the invention relates to a method for preparing nano graphene powder, in particular to a method for preparing nano graphene powder by plasma chemical vapor phase synthesis method.
- the method has the least number of graphene layers (2-10 layers), The structure is complete, the single layer has large diameter, low oxygen content, no sulfur, low content of metal impurities, and can realize continuous industrial production, and belongs to the field of chemical technology.
- Graphene is a two-dimensional material composed of a single layer of carbon atoms. Since its discovery in 2004, it has continuously demonstrated its excellent performance. Graphene is favored for its excellent light transmittance, large thermal conductivity, and extremely low resistivity. It is known as the next generation material that triggered the industrial revolution.
- the main methods for preparing graphene include mechanical stripping method, solvent stripping method, chemical vapor deposition method, crystal epitaxial growth method, redox method and the like.
- the first two stripping methods have low production efficiency: the chemical vapor deposition method and the crystal epitaxial growth method have high cost, complicated operation, and cannot produce large-area graphene; while the redox method has a low cost and simple process, but the prepared graphene The structure defects are large and the content of impurities is large. Therefore, it is imperative to develop a new graphene production process.
- the invention aims to provide a method for preparing nano graphene powder by plasma chemical vapor phase synthesis method, which has the advantages of small number of layers, complete structure, low oxygen content, no sulfur content and large-scale industrialization by plasma chemical vapor phase synthesis.
- Production of graphene Compared with the graphene oxide prepared by chemical oxidation and stripping of graphite powder in the prior art, the conjugated network has no serious functionalization, and does not require reduction treatment and other chemical modification, and the obtained graphene product Integrity and conductivity far exceed that of graphene oxide.
- the method for preparing nano graphene powder by the plasma chemical vapor phase synthesis method of the invention is as follows:
- methane as a raw material, nitrogen gas is introduced into the top, and methane is ionized into carbon ions and hydrogen ions under the ionization of the plasma arc, wherein the carbon ions are re-arranged in the reactor to form a structurally complete graphene powder.
- the hydrogen ion is combined into a hydrogen gas discharge, and the reaction is calculated by the gas flow meter, and the graphene powder is guided into the powder collector through the air flow. No catalyst or reducing agent needs to be added during the entire production process.
- the partial pressure of methane is 0.8-0.9 MPa
- the flow rate is 8 m 3 ⁇ h -1
- the partial pressure of nitrogen is 0.5-0.6 MPa
- the flow rate is 11 m 3 ⁇ h -1 .
- the plasma generator uses nitrogen as the working medium; the plasma generator has a working voltage of 280-300V and a direct current of 190-200A; the plasma arc temperature can reach 3000 °C, and the output power can reach 150kw.
- the methane is subjected to impurity removal treatment to achieve a purity of 98% or more to ensure the purity of graphene:
- the working voltage of the plasma generator is 280-300V and the load current is 190-200A.
- the reaction chamber starts to generate under the ionization of the positive electrode 4 of the plasma generator and the negative electrode 5 of the plasma generator. Plasma arc.
- the plasma arc temperature is raised to 3000 ° C, at which time the temperature in the reactor reaches 900 ° C.
- the methane partial pressure is set to 0.8-0.9 MPa, and the methane gas enters the reaction furnace 3, and the methane starts to ionize into carbon atoms and hydrogen atoms and rearranges.
- the powder Under the action of the air guiding device 7, the powder is discharged from the discharge pipe 6 by gravity sedimentation and then reaches the powder collector 8. After it is completely cooled, the graphene powder can be obtained.
- Figure 1 is a transmission electron microscope (TEM) photograph of graphene prepared by the present invention, showing that the graphene is slightly wrinkled and well dispersed.
- FIG. 2 is a high-resolution transmission electron microscope (HRTEM) photograph of graphene prepared by the present invention. It can be seen from the figure that graphene has good stratification, and the test results show that the graphene sheet layer has a small layer structure. Has a larger diameter structure.
- HRTEM transmission electron microscope
- Figure 3 is a high angle annular dark field image (HAADF) of the filtered graphene showing that the graphene crystallizes well.
- HAADF high angle annular dark field image
- Figure 4 is an XRD pattern of graphene, and it can be seen that the peaks are very concentrated.
- FIG. 5 is a photograph of selected area electron diffraction (SAED) of graphene prepared by the present invention showing diffraction rings of graphite and graphene.
- SAED selected area electron diffraction
- Fig. 6 is an elemental detection report of graphene, in which the element content is extremely small.
- Figure 7 is a Raman spectrum of graphene prepared by the present invention.
- Figure 8 is a reaction apparatus for preparing graphene of the present invention.
- 1 methane feed pipe 1 methane feed pipe, 2 top blowing nitrogen feed pipe, 3 reaction furnace, 4 plasma generator positive electrode, 5 plasma generator negative electrode, 6 discharge pipe, 7 air intake device, 8 powder collector.
- the methane feed pipe 1 is connected to the liquid methane tank, and the top blowing nitrogen feed pipe 2 is connected to the liquid nitrogen tank.
- the methane is subjected to impurity removal treatment to achieve a purity of 98% or more to ensure the purity of graphene:
- the working voltage of the plasma generator is 280V and the load current is 190A.
- the plasma arc starts to be generated in the reaction chamber under the ionization of the positive electrode 4 of the plasma generator and the negative electrode 5 of the plasma generator.
- the plasma arc temperature is raised to 3000 ° C, at which time the temperature in the reactor reaches 900 ° C.
- the methane partial pressure is set to 0.8 MPa, and the methane gas enters the reaction furnace 3.
- the methane starts to ionize into carbon atoms and hydrogen atoms and rearranges.
- the powder is discharged from the discharge pipe 6 by gravity sedimentation to the powder collector 8, and after it is completely cooled, the graphene powder can be obtained.
- the methane is subjected to impurity removal treatment to achieve a purity of 98% or more to ensure the purity of graphene;
- the working voltage of the plasma generator is 300V and the load current is 200A.
- the plasma arc starts to be generated in the reaction chamber under the ionization of the positive electrode 4 of the plasma generator and the negative electrode 5 of the plasma generator.
- the plasma arc temperature is raised to 3000 ° C, at which time the temperature in the reactor reaches 900 ° C.
- the methane partial pressure is set to 0.9 MPa, and the methane gas enters the reaction furnace 3.
- the methane starts to ionize into carbon atoms and hydrogen atoms and rearranges.
- the powder is discharged from the discharge pipe 6 by gravity sedimentation to the powder collector 8, and after it is completely cooled, the graphene powder can be obtained.
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Abstract
一种等离子化学气相合成法制备纳米石墨烯粉体的方法,以甲烷为原料,以氮气为工作介质,甲烷在等离子弧的电离作用下电离为碳离子和氢离子,其中碳离子在反应器内重新呈网络状排布从而生成结构完整的石墨烯粉体,氢离子结合为氢气排出,石墨烯粉体经过气流引导进入收粉器中。该方法制备的石墨烯层数少(2-10层),结构完整,单层片径大,含氧量低、不含硫、金属杂质含量低,并可实现连续化产业化生产。
Description
本发明涉及一种纳米石墨烯粉体的制备方法,具体地说是一种等离子化学气相合成法制备纳米石墨烯粉体的方法.该方法制备的石墨烯层数少(2-10层),结构完整,单层片径大,含氧量低、不含硫、金属杂质含量低,并可实现连续化产业化生产,属于化工技术领域。
石墨烯(Graphene)是一种由单层碳原子构成的二维材料.自从2004年被发现以来,不断向世人展现出它优异的性能。石墨烯因其出色的透光率,巨大的导热系数,极低的电阻率而备受亲睐,被誉为引发产业革命的下一代材料。目前,制备石墨烯的主要方法有:机械剥离法、溶剂剥离法、化学气相沉积法、晶体外延生长法、氧化还原法等等。其中,前两种剥离法生产效率低:化学气相沉积法和晶体外延生长法成本高、操作复杂且无法生产大面积石墨烯;而氧化还原法虽成本底、工艺简单,但制备出的石墨烯结构缺陷较大且杂质含量较多。因此,开发出一种新的石墨烯生产工艺势在必行。
三、发明内容
本发明旨在提供一种等离子化学气相合成法制备纳米石墨烯粉体的方法,通过等离子化学气相合成法制备出层数少、结构完整、含氧量低、不含硫、可大规模产业化生产的石墨烯。与现有技术中将石墨粉末经化学氧化及剥离而制备出的氧化石墨烯相比,其共轭网络无严重的官能化,不需要经过还原处理以及其他的化学修饰,得到的石墨烯产物的完整性及导电力远远超过氧化石墨烯。
本发明等离子化学气相合成法制备纳米石墨烯粉体的方法如下:
以甲烷作为原料,通入顶吹氮气,甲烷在等离子弧的电离作用下电离为碳离子和氢离子,其中碳离子在反应器内重新呈网络状排布从而生成结构完整的石墨烯粉体,氢离子结合为氢气排出,通过气体流量计计算反应完全,石墨烯粉体经过气流引导进入收粉器中。整个生产过程中不需添加任何催化剂、还原剂。
反应过程中,甲烷的分压为0.8-0.9MPa,流速为8m3·h-1;氮气的分压为0.5-0.6MPa,流速为11m3·h-1。
等离子发生器以氮气为工作介质;等离子发生器的工作电压280-300V,直流电流190-200A;等离子弧温度可达到3000℃,输出功率可达150kw。
反应方程式为:
CH4→C+2H2
具体反应过程如下:
1、对甲烷进行除杂处理,使其纯度达到98%以上从而保证石墨烯的纯度:
2、接通等离子发生器电源,等离子发生器的工作电压280-300V、负载电流190-200A,反应室内在等离子发生器正极4和等离子发生器负极5的电离作用下开始产生
等离子弧。
3、打开顶吹氮气输料管2,氮气分压设定为0.5-0.6MPa。
4、将等离子弧温度升至3000℃,此时反应炉内温度达到900℃。
5、打开甲烷输料管1,甲烷分压设为0.8-0.9MPa,使甲烷气体进入反应炉3,甲烷开始电离为碳原子与氢原子并重新排列。
6、10分钟后关闭等离子发生器电源,并将反应炉冷却至室温。
7、关闭甲烷输料管1与顶吹氮气输料管2。
8.在引风装置7的作用下,粉体由出料管6经过重力沉降除杂处理后到达收粉器8,待其完全冷却后即可得到石墨烯粉体。
本发明制备的石墨烯具有以下优点:
1、单层片径大:由电镜照片可以直观看出,由等离子气相化学合成法生产的石墨烯不仅层数少,而且片径大,通用性极好。
2,纯度高:由于整个合成过程中不添加任何催化剂,因此其纯度高,杂质含量少。
3、层数少:石墨烯的高分辨透射电镜(HRTEM)照片显示该石墨烯为少层结构(2-10层)。
4、结构完整:经过滤波处理的石墨烯高角环形暗场像(HAADF),显示该石墨烯结晶良好。
5、成本低:以甲烷为原料,以等离子气相化学合成为合成方法大大降低了生产成本,已达到2kg/h的单线生产能力,
图1是本发明制备的石墨烯的透射电子显微镜(TEM)照片,显示该石墨烯略有褶皱,分散良好。
图2是本发明制备的石墨烯的高分辨透射电镜(HRTEM)照片,从图中可看出,石墨烯具有较好的分层,通过测试结果得知,石墨烯片层为少层结构,有较大的片径结构。
图3是经过滤波处理的石墨烯的高角环形暗场像(HAADF),显示该石墨烯结晶良好。
图4是石墨烯的XRD图,可以看出其波峰非常集中突出。
图5是本发明制备的石墨烯的选区电子衍射(SAED)照片,显示了石墨和石墨烯的衍射环。
图6是石墨烯的元素检测报告,可见其中元素含量极少。
图7是本发明制备的石墨烯的拉曼谱图。
图8是本发明制备石墨烯的反应装置。其中,1甲烷输料管,2顶吹氮气输料管,3反应炉,4等离子发生器正极,5等离子发生器负极,6出料管,7引风装置,8收粉器。甲烷输料管1与液态甲烷罐连接,顶吹氮气输料管2与液氮罐连接。
以下结合附图对本发明的技术方案进行说明,应当了解,此处所描述的实施例仅用于说明和解释本发明,并不限定本发明。
实施例1:
1、对甲烷进行除杂处理,使其纯度达到98%以上从而保证石墨烯的纯度:
2、接通等离子发生器电源,等离子发生器的工作电压280V、负载电流190A,反应室内在等离子发生器正极4和等离子发生器负极5的电离作用下开始产生等离子弧。
3、打开顶吹氮气输料管2,氮气分压设定为0.5MPa。
4、将等离子弧温度升至3000℃,此时反应炉内温度达到900℃。
5、打开甲烷输料管1,甲烷分压设为0.8MPa,使甲烷气体进入反应炉3,甲烷开始电离为碳原子与氢原子并重新排列。
6、10分钟后关闭等离子发生器电源,并将反应炉冷却至室温。
7、关闭甲烷输料管1与顶吹氮气输料管2。
8、在引风装置7的作用下,粉体由出料管6经过重力沉降除杂处理后到达收粉器8,待其完全冷却后即可得到石墨烯粉体。
实施例2:
1、对甲烷进行除杂处理,使其纯度达到98%以上从而保证石墨烯的纯度;
2、接通等离子发生器电源,等离子发生器的工作电压300V、负载电流200A,反应室内在等离子发生器正极4和等离子发生器负极5的电离作用下开始产生等离子弧。
3、打开顶吹氮气输料管2,氮气分压设定为0.6MPa。
4、将等离子弧温度升至3000℃,此时反应炉内温度达到900℃。
5、打开甲烷输料管1,甲烷分压设为0.9MPa,使甲烷气体进入反应炉3,甲烷开始电离为碳原子与氢原子并重新排列。
6、10分钟后关闭等离子发生器电源,并将反应炉冷却至室温。
7、关闭甲烷输料管1与顶吹氮气输料管2。
8、在引风装置7的作用下,粉体由出料管6经过重力沉降除杂处理后到达收粉器8,待其完全冷却后即可得到石墨烯粉体。
表1实施例1制备得到的石墨烯的性能检测数据
由表1可见,气相合成的石墨烯的纯度非常高,相对现在市面上流行的氧化法合成的石墨烯,其氧含量及硫含量要小很多,且结构完整性、比表面积等也得到很大的改善。
需要注意的是,以上所举的是本发明具体实施的例子。而本发明在原料的选择以及等离子体工质的选择上可以有许多变形。本领域的技术人员从本发明中所导出或发展的变形,均在本发明的保护范围之内。
Claims (5)
- 一种等离子化学气相合成法制备纳米石墨烯粉体的方法,其特征在于:以甲烷为原料,以氮气为工作介质,甲烷在等离子弧的电离作用下电离为碳离子和氢离子,其中碳离子在反应器内重新呈网络状排布从而生成结构完整的石墨烯粉体,氢离子结合为氢气排出,石墨烯粉体经过气流引导进入收粉器中。
- 根据权利要求1所述的方法,其特征在于:反应过程中,甲烷的分压为0.8-0.9MPa,氮气的分压为0.5-0.6MPa。
- 根据权利要求1或2所述的方法,其特征在于:反应过程中,甲烷的流速为8m3·h-1,氮气的流速为11m3·h-1。
- 根据权利要求1所述的方法,其特征在于:等离子发生器的工作电压280-300V,直流电流190-200A。
- 根据权利要求1所述的方法,其特征在于:反应过程中等离子弧温度设置为3000℃。
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CN112028059A (zh) * | 2020-09-09 | 2020-12-04 | 宁波中冶电子科技有限公司 | 一种石墨烯的制备装置及其应用 |
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