• 한국세라믹학회지
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• 제52권3호
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• pp.173-179
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• 2015

We report the facile synthesis of graphene-$CdLa_2S_4$ composite through a facile solvothermal method at low temperature. The as-prepared products were characterized by X-ray diffraction (XRD) and by Scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and BET analysis, revealing the uniform covering of the graphene nanosheet with $CdLa_2S_4$ nanocrystals. The as-prepared samples show a higher efficiency for the photocatalytic degradation of typical MB dye compared with P25 and $CdLa_2S_4$ bulk nanoparticles. The enhancement of visible-light-responsive photocatalytic properties by decolorization of Rh.B dye may be attributed to the following causes. Firstly, graphene nanosheet is capable of accepting, transporting and storing electrons, and thus retarding or hindering the recombination of the electrons with the holes remaining on the excited $CdLa_2S_4$ nanoparticles. Secondly, graphene nanosheet can increase the adsorption of pollutants. The final cause is that their extended light absorption range. This work not only offers a simple way to synthesize graphene-based composites via a one-step process at low temperature but also a path to obtain efficient functional materials for environmental purification and other applications.

• Korean Chemical Engineering Research
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• 제48권3호
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• pp.292-299
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• 2010

그래핀(graphene)은 $sp^2$ 탄소원자들이 벌집 격자를 이룬 형태의 2차원 나노시트를 의미하며, 높은 비표면적(이론치 $2600m^2\;g^{-1}$)과 우수한 전기전도도(전형치 $8{\times}10^5S\;cm^{-1}$) 및 기계적 강도로 인해 리튬이온전지의 음전극 활물질 및 초고용량 커패시터의 전극 활물질로서 사용 가능성이 높아지고 있다. 본 총설에서는 현재까지 알려진 그래핀 나노시트와 그래핀을 기반으로 하는 나노복합체의 제조법을 소개하고, 이를 리튬이온전지와 초고용량 커패시터의 전극소재로 적용하였을 때의 특성을 그 나노구조적 관점과 연관하여 논의하였다.

• Carbon letters
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• 제14권1호
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• pp.51-54
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• 2013

In this study, polyaniline (PANI)/graphene nanosheet (GNS) composites were synthesized through chemical oxidation polymerization by changing the weight ratio of aniline monomers. To examine the morphological structure of the composites, scanning electron microscopy and transmission electron microscopy (TEM) were conducted. TEM results revealed that fibril-like PANI with a diameter of 50 nm was homogeneously coated on the surface of the GNS. The electrochemical properties of the composites were studied by cyclic voltammetry in 1 M $H_2SO_4$ electrolyte. Among the prepared samples, the PANI/GNS (having 40 wt% aniline content) showed the highest specific capacitance, 528 $Fg^{-1}$, at 10 $mVs^{-1}$. The improved performance was attributed to the GNS, which provides a large number of active sites and good electrical conductivity. The resulting composites are promising electrode materials for high capacitative supercapacitors.

• 한국재료학회지
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• 제30권12호
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• pp.641-649
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• 2020

A facile microwave assisted solvothermal process is designed for fabricating SnS nanoparticles decorated on graphene nanosheet, which used as visible light driven photocatalyst. Some typical characterization techniques such as XRD, FT-IR, SEM with EDX analysis, and TEM and BET analysis are used to analyse the physical characteristics of as-prepared samples. Spherical SnS nanoparticles are uniformly dispersed on the surface of graphene nanosheet due to ammonia, which can prevent the aggregation of graphene oxide. Meanwhile, microwave radiation provides fast energy that promotes the formation of spherical SnS nanoparticles within a short time. The visible light photocatalytic activity of as-prepared SnS-GR nanocomposites is analysed through photodegradation efficiency of methylene blue with high concentration. According to the higher photocatalytic property, the as-prepared SnS-GR nanocomposites can be expected to be an efficient visible light driven photocatalyst. After five cycles for decolorization, the rate decreases from 87 % to 78 % (about 9 %). It is obvious that the photocatalytic activity of SnS-GR nanocomposite has good repeatability.

• Journal of Microbiology and Biotechnology
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• 제25권2호
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• pp.145-151
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• 2015

Graphene is a next-generation biomaterial with increasing biomedical applicability. As a new class of one-atom-thick nanosheets, it is a true two-dimensional honeycomb network nanomaterial that attracts interest in various scientific fields and is rapidly becoming the most widely studied carbon-based material. Since its discovery in 2004, its unique optical, mechanical, electronic, thermal, and magnetic properties are the basis of exploration of the potential applicability of graphene. Graphene materials, such as graphene oxide and its reduced form, are studied extensively in the biotechnology arena owing to their multivalent functionalization and efficient surface loading with various biomolecules. This review provides a brief summary of the recent progress in graphene and graphene oxide biological research together with current findings to spark novel applications in biomedicine. Graphene-based applications are progressively developing; hence, the opportunities and challenges of this rapidly growing field are discussed together with the versatility of these multifaceted materials.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.60-60
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• 2015

Nanosheets of graphene and related 2D materials have attracted much attention due to excellent physical, chemical and mechanical properties. Single-layer graphene (SLG) was first synthesized by Blakely et al in 1974 [1]. Following his achievements, we initiated the growth and characterization of graphene and h-BN on metal substrates using surface segregation and precipitation in 1980s [2,3]. There are three important steps for nanosheet growth; surface segregation of dopants, surface reaction for monolayer phase, and subsequent 3-D growth (surface precipitation). Surface phase transition was clearly demonstrated on C-doped Ni(111) by in situ XPS at elevated temperatures [4]. The growth mode was clarified by inelastic background analysis [5]. The surface segregation approach has been applied to C-doped Pt(111) and Pd(111), and controllable growth of SLG has been demonstrated successfully [6]. Recently we proposed a promising method for producing SLG fully covering an entire substrate using Ni films deposited on graphite substrates [7]. A universal method for layer counting has been proposed [8]. In this paper, we will focus on the effect of competitive surface-site occupation between carbon and other surface-active impurities on the graphene growth. It is known that S is a typical impurity of metals and the most surface-active element. The surface sites shall be occupied by S through surface segregation. In the case of Ni(110), it is confirmed by AES and STM that the available surface sites is nearly occupied by S with a centered $2{\times}2$ arrangement. When Ni(110) is doped with C, surface segregation of C may be interfered by surface active elements like S. In this case, nanoscopic characterization has discovered a preferred directional growth of SLG, exhibiting a square-like shape (Fig. 1). Also the detailed characterization methodologies for graphene and h-BN nanosheets, including AFM, STM, KPFM, AES, HIM and XPS shall be discussed.

• 공업화학
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• 제31권6호
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• pp.607-611
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• 2020

본 연구에서는 그래파이트로부터 직접적으로 그래핀 복합체를 합성하는 방법을 이용하여 Au/TiO2/그래핀 복합체를 합성하였다. 계면활성제를 이용하여 박리된 그래파이트로부터 합성된 그래핀 복합체에서 TiO2는 아주 얇은 시트 형태로 그래핀 표면에 분포되어있고 10 nm 미만의 Au 나노입자들이 TiO2 시트 표면 위에 골고루 분포되어 있다. 이렇게 만들어진 그래핀 복합체를 이용하여 다양한 염료의 광분해 반응에 적용하였다. 이들 중 가장 광분해 활성에 뛰어난 것으로 나타난 염료는 메틸렌블루(91.6%)였으며 로다민 B(31.0%)에서는 광분해 특성이 뛰어나지 않는 것으로 나타났다.

• 한국재료학회지
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• 제32권1호
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• pp.1-8
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• 2022

In this investigation, Bi₂MoO₆ deposited graphene nanocomposite (BMG) was synthesized using a simple microwave assisted hydrothermal synthesis method. The synthesized BMG nanocomposite was characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy with energy dispersive X-ray analysis, and photocurrent analysis. The study revealed that the catalysts prepared have high crystalline nature, enhanced light responsive property, high catalytic activity, and good stability. XRD results of BMG composite exhibit a koechlinite phase of Bi₂MoO₆. The surface property is shown by SEM and TEM, which confirmed a homogenous composition in the bulk particles of Bi₂MoO₆ and nanosheets of graphene. The catalytic behavior was investigated by the decomposition of Rhodamine B as a standard dye. The results exhibit excellent yields of product derivatives at mild conditions under ultrasonic/visible light-medium. Approximately 1.6-times-enhanced sono-photocatalytic activity was observed by introduction of Bi₂MoO₆ on graphene nanosheet compared with control sample P25 during 50 min test.

• 멤브레인
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• 제29권3호
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• pp.130-139
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• 2019

그래핀, 제올라이트, metal-organic frameworks (MOF)s 등 다양한 나노 소재를 이차원 나노쉬트 형태로 제조하고, 이를 이용한 초박막 고성능 분리막을 개발하고자 하는 연구가 활발히 진행되고 있다. 특히, 산화그래핀의 경우, 2000년대 초반에 관련 연구가 시작된 이후, 다양한 합성 및 박막 코팅 기술이 축적되어 있어 빠른 속도로 분리막 분야에 응용되고 있다. 다층으로 적층된 산화그래핀 박막은 층간 거리를 조절함에 따라 물리적 거름막으로 작용할 수 있으며, 또한 표면의 기능기 및 삽입된 물질과 거르는 물질 간의 상호작용을 제어함에 따라 다양한 물질의 선택적 분리가 가능하다. 본 총설에서는 산화그래핀의 나노여과막 응용분야에 관하여 중점적으로 다루고자 한다. 본고에서는, 다양한 용매 내에서 산화그래핀 박막의 분리 기작 및 성능에 영향을 미치는 핵심 요소들에 대해 요약하였으며, 그 외 산화그래핀 기반 분리막의 실질적인 상용화에 필요한 핵심 기술요소 및 개발 동향에 대하여 논하고자 한다.

• 진공이야기
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• 제5권2호
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• pp.18-22
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• 2018

wo dimensional (2D) van der Waals (vdW) nanosheet semiconductors have recently attracted much attention from researchers because of their potentials as active device materials toward future nano-electronics and -optoelectronics. This review mainly focuses on the features and applications of state-of-the-art vdW 2D material devices which use transition metal dichalcogenides, graphene, hexagonal boron nitride (h-BN), and black phosphorous: field effect transistors (FETs), complementary metal oxide semiconductor (CMOS) inverters, Schottky diode, and PN diode. In a closing remark, important remaining issues of 2D vdW devices are also introduced as requests for future electronics and photonics applications.