Hefei Research Institute takes carbon composite coated transition metal carbide nanoparticle synthesis

Researcher Liang Changhao, a researcher at the Hefei Institute of Physical Science, Chinese Academy of Sciences, recently made progress in the synthesis of carbon-coated transition metal carbide (TMC/C) nanoparticles. The relevant results were published in the full text in the Carbon magazine (Carbon, 2016, 100, 590-599).

Transition metal carbide (TMC) is a special material with covalent bonds, ionic bonds and metal bonds coexisting, so it exhibits unique electrical and mechanical properties. However, during the application process, the carbon on the surface of the material is easily oxidized, resulting in a change in the surface structure of the material, which ultimately affects its physical and chemical properties. In addition, nano-scale TMCs are prone to aggregation during application, resulting in recrystallization of the material and a reduction in catalytically active sites. In recent years, carbon-coated nanomaterials have received much attention because of their unique physical and chemical properties, such as surface functionalization, oxidation resistance, resistance to acid and alkali corrosion, and not easily agglomerated. Therefore, they have been widely used for magnetic data storage and electronic applications. Catalysis, bioengineering and other fields. In summary, if a carbon material with high surface stability is prepared as a protective layer of TMC and a unique TMC/C core-shell structure is formed, then the composite material with this specific structure may become ideal in electrochemical energy storage equipment. The electrode material. Therefore, it is of great significance to develop a simple, effective, and mildly controllable method for the preparation of uniform size carbon-coated transition metal carbide (TMC/C) nanomaterials.

Recently, based on the Liquid Ablation in Liquids (LAL) technology, researchers at the Institute of Solids have successfully prepared a series of TMC/C core-shell nanomaterials, including TaC, using absolute ethanol and acetone as liquid media. /C, NbC/C, HfC/C, and MoC/C (Figure 1 af). The structural analysis shows that the internal TMC of this type of material behaves like a cubic phase crystal structure of NaCl type and the shell is amorphous carbon with different thickness. The results of LAL experiments show that the type of liquid dispersion medium plays a decisive role in the formation of TMC/C core-shell structure. For example, the target of tantalum in acetone can form the core-shell structure of carbon-coated transition group metal carbides, TMC/C, while nanomaterials of similar structure cannot be obtained in absolute ethanol. This experiment shows that acetone is lower than anhydrous. Ethanol is more conducive to the formation of carbon coatings. Combining these experimental results, researchers at the Solid Institute proposed a possible mechanism for the formation of TMC/C core-shell structures. As shown in Fig. 1g, in the liquid medium, the pulsed laser interacts with the solid target and forms a high-temperature, high-pressure plasma plume at the solid-liquid interface. The plasma plume undergoes rapid adiabatic expansion in the liquid medium successively. And quenching process, eventually annihilated. In this process, at the interface between the plasma plume and the liquid medium, the peeled components of the target quickly combine with the carbon-containing components decomposed by the organic liquid medium, and nucleate and grow into metal carbide nanoparticles, at the same time Supersaturated carbon precipitates on the surface, eventually forming amorphous carbon-coated core-shell nanoparticles after the quenching process. This study provides a simple, green universal method for the controlled synthesis of TMC/C core-shell structures. In addition, in order to investigate the electrical properties of TMC/C core-shell nanomaterials, researchers at the Solid State Institute of Technology took TaC/C core-shell nanostructures as an example to design a series of comparative experiments and found that in the application of supercapacitors, such structures Nanomaterials exhibit superior rate and cycling performance (Figure 2).

This work was supported by the National Key Basic Research and Development Program (No. 2014CB931704), the National Natural Science Foundation of China, and the World Premier International (WPI) Center for Materials Nano-architectonics (MANA).

Breathable Floor Protector

Breathable Floor Protector,Carpet Floor Protectors,Adhesive Floor Protector,Baby Floor Protection

Suzhou Surface Protective New Material Technology Co.,Ltd , https://www.surfaceprotective.com

Posted on