Carbon Nanotubes: Unique and Promising Prospects

Since it was first discovered by NEC Japan in 1991, carbon nanotubes have developed into new functional materials and structural materials with excellent performance. At present, all countries in the world are competing to invest in R&D in preparation and application, and they are expected to occupy the commanding heights in this field. Scientists predict that carbon nanotubes will become the most promising one-dimensional nanomaterials, nanoelectronic device materials, and next-generation flat panel display materials in the 21st century.

High-tech applications have great potential

Yan Zuolong, a researcher of Chengdu Organic Chemicals, Chinese Academy of Sciences, affirmed that “carbon nanotubes can be used in many high-tech fields.” He specifically stated: “The once-catalyzed application of carbon nanotubes is expected to greatly increase the activity of the reaction and Selectivity produces enormous economic benefits."

In addition, due to its special structure and dielectric properties, carbon nanotubes exhibit strong broadband microwave absorption properties, as well as light weight, variable electrical conductivity, high temperature oxidation resistance, and good stability. , is a promising ideal microwave absorber, it may be used for invisible materials, electromagnetic shielding materials or darkroom absorbing materials.

Due to their large specific surface area and large surface atomic ratio, carbon nanotubes exhibit special electronic and surface effects. As a new member of the nanomaterial family, the special structure and surface properties of carbon nanotubes, excellent hydrogen storage capacity, and metal and semiconductor conductivity have great potential for hydrogenation, dehydrogenation, and selective catalytic reactions. .

Research and exploration aimed at low-cost preparation

To realize industrial applications of carbon nanotubes, it is first necessary to solve the problem of mass production at a low cost.

The researcher of Institute of Metals, Chinese Academy of Sciences stressed that: “At present, there are two major problems in carbon nanotube research: First, there is a lack of in-depth understanding of the growth mechanism, which limits the controllable preparation and quantitative production of carbon nanotubes; second, the lack of scale applications. Technological exploration.” This has also presented researchers with multiple challenges, such as the low cost, large-scale controllable preparation of single-walled, double-walled carbon nanotubes, the controlled preparation and regulation of carbon nanotube structures, and the growth mechanism of carbon nanotubes. Elucidation, the construction and assembly of carbon nanotube devices, the comprehensive utilization of excellent performance of carbon nanotubes, and the development of large-scale application technologies.

Yu Zuolong's researcher introduced that there are currently three methods for preparing carbon nanotubes, namely arc discharge, laser ablation, and fixed-bed catalytic cracking. As a whole, the carbon nanotubes produced by the first two methods coexist with other forms of carbon products, and there are deficiencies in separation, purification, low yield, and difficulty in scale; the catalysts used in the third method must be in the form of thin layers. There will be good results when it is unfolded, otherwise the utilization of the catalyst will be low, and the output will also be difficult to increase.

"To achieve mass production of carbon nanotubes, we must first solve the problem of continuous catalyst release and the timely derivation of catalysts and products." Yu Zuolong said. Their research shows that the continuous preparation of carbon nanotubes can be achieved through a special reaction device and process, so as to achieve the purpose of low-cost, large-scale preparation of carbon nanotubes. For example, the use of a moving bed catalytic cracking reactor enables the continuous manufacture of carbon nanotubes of a design size, thereby significantly reducing production costs and providing assurance for the industrial application of carbon nanotubes.

Many world-leading achievements in China

During the interview, the reporter learned that Chinese scientists have devoted great efforts in the field of carbon nanotubes. New discoveries and new applications have emerged in an endless stream and many world-leading results have been achieved. For example, the Si Si Shen Academician of the Physics Institute of the Chinese Academy of Sciences (1996) developed a method for effectively preparing large-area, high-density, and oriented carbon nanotubes in 1996, which opened the way for the preparation of arrayed carbon nanotubes. Subsequently, the research group also successively produced the longest and finest carbon nanotubes.

Also in 1996, Chengdu Organic Chemicals Co., Ltd. started the research on carbon nanotube preparation technology; in June 2000, for the first time in the world, it realized the continuous batch production of carbon nanotubes; in November 2001, it was the largest in Asia at that time. Carbon nanotube production base. Today, the company has 7 patents for carbon nanotubes that cover manufacturing processes, catalysts, and devices. The carbon nanotube products developed have reached 33 varieties, involving different diameters, lengths, purity, and surface groups. Product Series.

In 2009, a carbon nanotube preparation method invented by the research group of Tang Tao, a researcher of Changchun Institute of Applied Chemistry at the Chinese Academy of Sciences, obtained the authorization of the US Trademark Patent Office on the basis of six Chinese invention patents. This achievement organically combines the high-efficiency carbonization technology of polymers with the preparation technology of carbon nanomaterials, and opens up new ways for synthesizing carbon nanomaterials, improving the flame-retardant properties of polymers, and recycling high-value recycled plastics.

In 2008, the College of Chemistry and Chemical Engineering of Xiamen University developed a new catalyst and technology for the preparation of carbon nanotubes. So far, Xiamen University has jointly developed new polymer composite materials with carbon nanotubes, high-performance carbon nanotube capacitors/batteries, and carbon nanotube catalyst materials. In June 2010, Xiamen University invested a 100 kg high-purity, multi-walled carbon nanotubes production facility in Kuqa Chemical Park in Xinjiang. The product has been used by more than 20 universities and research institutes at home and abroad as research materials.