Young-Jung Heo

Facile Synthesis of MgO-Modified Carbon Adsorbents with Microwave- Assisted Methods: Effect of MgO Particles and Porosities on CO 2 Capture

In this study, magnesium oxide (MgO)-modified carbon adsorbents were fabricated using a nitrogen-enriched carbon precursor by microwave-assisted irradiation for CO2 capture. The X-ray diffraction (XRD) patterns showed the characteristic diffraction peaks of MgO at 43° and 62.5°, and no impurities were apparent. By changing the microwave reaction time, the spherical structure of the parent material was transformed to a hybrid structure with MgO crystalline particles in a carbon matrix. The morphology evolution and properties of the prepared materials were also investigated using transmission electron microscopy and N2 adsorption, respectively. On optimising the conditions, the prepared sample attained a high CO2 uptake of 1.22 mmol/g (5.3 wt.%) under flue gas conditions (15% CO2 in N2). It was found that MgO affected the CO2 capture behaviour by enhancing the fundamental characteristics of the carbon surfaces.

A review: role of interfacial adhesion between carbon blacks and elastomeric materials

Abstract Carbon blacks (CBs) have been widely used as reinforcing materials in advanced rubber composites. The mechanical properties of CB-reinforced rubber composites are mostly controlled by the extent of interfacial adhesion between the CBs and the rubber. Surface treatments are generally performed on CBs to introduce chemical functional groups on its surface. In this study, we review the effects of various surface treatment methods for CBs. In addition, the preparation and properties of CB-reinforced rubber composites are discussed. Key words: rubber, carbon blacks, surface treatments, interfacial adhesion 1. Introduction Rubber exhibits superior viscoelastic properties and improves the lifespan of products which continue to be transformed. At first, natural rubber (NR), which is composed of isoprene monomers, was obtained from nature. Later, as industries developed, synthetic rubbers were produced to supplement the production of NR. In particular, studies have been conducted on a new kind of rubber that is made of butadiene, namely, a copolymer of acrylonitrile butadiene rubber (NBR) and styrene butadiene rubber (SBR) as shown in Fig. 1 [1-6].However, rubber lacks sufficient physical strength, which makes it unsuitable for various applications. For this reason, fillers, such as carbon materials and silica, are added to rubber to form rubber composites with improved mechanical behaviors [7-27].In recent years, carbon materials have been widely used as reinforcing agents in high-per -formance composite materials [28-35], adsorbents [36], electrochemistry [37], and energy storage materials [38]. Among various carbon materials used as reinforcing agents, carbon blacks (CBs) are the oldest carbon derivatives produced by the incomplete combustion of petroleum products, such as fluid catalytic cracking tar and coal tar. Moreover, the particle size, structure, and surface conditions of CBs (Fig. 2) make them popular reinforcing agents [19-21].CBs contain more than 95% amorphous carbon, and their particle sizes vary from 5 to 500 nm. The physical properties of CBs vary with the production method and the raw materials used, which makes them suitable for applications in various fields. The mixing ratio of CBs in automobile tires is 50%, while that in other rubber products is approximately 30%. Rela-tively large amounts of reinforced CBs should be added to NR to attain acceptable mechani-cal properties. Cohesion occurs between CB particles due to chemical and physical bonds. The chemical composition of CB aggregates is 90%–99% carbon, 0.1%–1.0% hydrogen, 0.2%–2.0% oxygen, and a small amount of sulfur and ash. In addition, oxygen-containing functional groups, such as the carboxyl, hydroxyl, and quinine groups, exist on the surfaces of CBs. These are called surface functional groups. These surface functional groups increase the chemical and physical bonding between the CBs particles and the rubber matrix [39-43]. Therefore, the addition of CBs to rubber results in the formation of composites with im-

Investigation of carbon dioxide adsorption by nitrogen-doped carbons synthesized from cubic MCM-48 mesoporous silica

Copyright

Prospective Synthesis Approaches to Emerging Materials for Supercapacitor

Abstract With the increasing need for electrochemical energy storage devices such as batteries and supercapacitors, energy storage materials are attracting special attention and such materials are rapidly being developed and reported. Although supercapacitors offer remarkable benefits, including high power capability, a long life cycle, and fast charge–discharge, they still have low storage capacity. Hence, considerable effort has focused on increasing their energy capabilities. Porous carbons, graphitic materials, conducting polymers, and transition metal oxides as active materials have frequently been reported and are continuously being studied. To improve the energy capabilities of those materials, various strategies have been implemented, including: (1) development of their specific surface area and pore size control, (2) prevention of stack problems, (3) improving their wettability to increase their practical contact area with the electrolyte, (4) use of hybrid nanomaterials with two or more materials. Furthermore, scalable, green, and efficient synthesis methods have been developed for the practical use of graphitic materials as active materials. In this chapter, we present a brief overview of the basic concepts of supercapacitors and active materials. Furthermore, the fundamentals, functionalities, challenges, and prospects of different classes of emerging materials for energy storage applications, such as those just mentioned, will be discussed.