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Vivek Dhand,이경엽,박수진,Garima Mittal 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.4 No.4
Chemical vapor deposition (CVD) is considered as a low-cost industrial technique for the mass production of carbon nanotubes (CNTs) which exhibit remarkable performance in various fields especially, in green technologies like, energy storage, green composites, solar cells etc. To optimize the yields, it is necessary to understand the role of different parameters affecting their production. In this research, the role of different spinel ferrites has been studied for the catalytic production of the CNTs with different morphologies (polymorphic nano carbons- PNCs) via CVD process. The characterization of the produced PNCs is done using X-ray diffraction, high-resolution Raman spectroscopy, field emission-scanning electron microscopy, and field emission-transmission electron microscopy. It is found that all the spinel ferrites behave differently during synthesis and produces different morphology of nanocarbons (tubes, fibers, beads etc.). Additionally, the thermal and magnetic properties of the produced PNCs are also compared through thermo-gravimetric analysis and vibrating sample magnetometer, respectively. It is found that all the samples show different thermal stability and weak ferromagnetic behavior.
Vivek Dhand,이경엽,J. Sarada Prasad,Y. Anjaneyulu 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.3
An in-house custom made high pressure adsorption/desorption unit has been designed and fabricated to study reversible hydrogen (H2) intake capacity, hysteresis, kinetics, plateau pressure of various nanomaterials, zeolites and metallic compounds, in the pressure range of 1≤P≤150 atm. The unit has been used to estimate H2 intake capacity of carbon nanofibers prepared by flame synthesis in the absence of catalyst. H2 adsorption studies have been carried out in the pressure range of 25–100 atm at 297 K. The maximum H2 intake capacity has been observed to be 3.7 wt% at 100 atm.
Dhand, Vivek,Hong, Soon Kyu,Li, Luhe,Kim, Jong-Man,Kim, Soo Hyung,Rhee, Kyong Yop,Lee, Hyung Woo Elsevier 2019 Composites Part B, Engineering Vol.160 No.-
<P><B>Abstract</B></P> <P>PVDF-CNT membranes were fabricated using thermally induced phase separation (TIPS) protocol. The membranes are extremely tensile, strong and robust. Membranes exhibit hydrophilic behavior with decreasing contact angle (CA < 90°) in saline environment. Crystal study (XRD) of membranes reveals ɑ-phased PVDF with hexagonal (002) oriented CNTs within the polymer matrix. The morphology (SEM) and thermal analysis (TGA) reveals that the material is made of several porous zones and the material is chemically and thermally stable up to 500 °C. Raman and FTIR spectrum shows ordered bands of the D and G with complete grafting of PVDF bonds with CNTs respectively.</P>
Vivek Dhand,Mandapati Venkateswer Rao,Garima Mittal,이경엽,박수진 한국물리학회 2015 Current Applied Physics Vol.15 No.3
An in-situ approach to synthesize lithiumegraphite nanotubes (LGN) is demonstrated using chemical vapour deposition (CVD). Lithium acetate was used as precursor and as a self-intercalating agent in the presence of copper. Methane was selected as the secondary carbon source. To synthesize lithiumegraphite nanotubes (LGN), CVD reactor was set to 500 ℃ in the presence of argon (200 sccm), hydrogen (40 sccm) and methane (75 sccm) gas under atmospheric conditions. X-ray diffraction shows that the samples are highly crystalline with the c-axis oriented toward the (002) and (111) planes of the graphitic carbon. High resolution transmission and scanning electron microscopic analyses of the samples shows that lithium has been doped into the layers of graphitic carbon matrix. They also show the formation of an alloy phase with distinctive lattice boundaries and stacked graphitic carbon with a small number of nanorods (lithium carbide). HR-Raman analysis shows the characteristic D and G bands of SP2 carbon with a narrow G band and broad D band indicating defects produced through doping. X-ray photoelectron spectroscopy results show the presence of predominant lithium and carbon peaks. Thermal analysis shows that the sample is stable up to 300 ℃ in air.
Dhand, Vivek,Rao, M. Venkateswer,Prasad, J.S.,Mittal, Garima,Rhee, Kyong Yop,Kim, Hyeon Ju,Jung, Dong Ho 한국탄소학회 2014 Carbon Letters Vol.15 No.3
Amorphous agglomerates of carbon nanospheres (CNS) with a diameter range of 10-50 nm were synthesized using the solution combustion method. High-resolution transmission elec-tron microscopy (HRTEM) revealed a densely packed high surface area of SP2-hybridized carbon; however, there were no crystalline structural components, as can be seen from the scanning electron microscopy, HRTEM, X-ray diffraction, Raman spectroscopy, and ther-mal gravimetric analyses. Electrochemical and thermo catalytic decomposition study results show that the material can be used as a potential electrode candidate for the fabrication of energy storage devices and also for the production of free hydrogen if such devices are used in a fluidized bed reactor loaded with the as-prepared CNS as the catalyst bed.
A Comprehensive Review of Graphene Nanocomposites: Research Status and Trends
Dhand, Vivek,Rhee, Kyong Yop,Ju Kim, Hyun,Ho Jung, Dong Hindawi Limited 2013 Journal of nanomaterials Vol.2013 No.-
<P>This paper provides a comprehensive review of the present trends in graphene research with an emphasis on graphene-based nanocomposites and their applications. Various synthesis routes have recently been devised for mass production of graphene to address the needs of the composite industry. This paper describes the worldwide scenario of research and patents being conducted in the field of graphene nanocomposites. It concludes with a discussion of the impact of graphene in composites and the future challenges to meeting industrial demands.</P>
Carbon nanotubes synthesis using diffusion and premix flame methods: a review
Garima Mittal,Vivek Dhand,Kyong Yop Rhee,Hyeon-Ju Kim,Dong Ho Jung 한국탄소학회 2015 Carbon Letters Vol.16 No.1
In recent years, flame synthesis has absorbed a great deal of attention as a combustion method for the production of metal oxide nanoparticles, carbon nanotubes, and other related carbon nanostructures, over the existing conventional methods. Flame synthesis is an energyefficient, scalable, cost-effective, rapid and continuous process, where flame provides the necessary chemical species for the nucleation of carbon structures (feed stock or precursor) and the energy for the production of carbon nanostructures. The production yield can be optimized by altering various parameters such as fuel profile, equivalence ratio, catalyst chemistry and structure, burner configuration and residence time. In the present report, diffusion and premixed flame synthesis methods are reviewed to develop a better understanding of factors affecting the morphology, positioning, purity, uniformity and scalability for the development of carbon nanotubes along with their correlated carbonaceous derivative nanostructures..
A review on carbon nanotubes and graphene as fillers in reinforced polymer nanocomposites
Garima Mittal,Vivek Dhand,이경엽,박수진,이위로 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
Recently, carbonaceous nanofillers such as graphene and carbon nanotubes (CNTs) play a promising roledue to their better structural, functional properties and broad range of applications in every field. Thispaper reviews the synthesis and properties of CNTs along with the use of graphene as a novelsubstitution to the nanotubes as fillers. This review also focuses on the issues related to the processing,dispersion and alignment of CNT within nanocomposites. Furthermore a comparative analysis has beencarried out between the importance of graphene and carbon nanotubes as fillers and their substantialchanges in mechanical and electrical properties of matrix.