Hydrogen Storage by Carbon Fibers Synthesized by Pyrolysis of Cotton Fibers

Maheshwar Sharon,Madhuri Sharon,Golap Kalita,Bholanath Mukherjee 한국탄소학회 2011 Carbon Letters Vol.12 No.1

Synthesis of carbon fibers from cotton fiber by pyrolysis process has been described. Synthesis parameters are optimized using Taguchi optimization technique. Synthesized carbon fibers are used for studying hydrogen adsorption capacity using Seivert's apparatus. Transmission electron microscopy analysis and X-ray diffraction of carbon fiber from cotton suggested it to be very transparent type material possessing graphitic nature. Carbon synthesized from cotton fibers under the conditions predicted by Taguchi optimization methodology (no treatment of cotton fiber prior to pyrolysis, temperature of pyrolysis 800℃, Argon as carrier gas and paralyzing time for 2 h) exhibited 7.32 wt% hydrogen adsorption capacity.

Platinum nanocomposites and its applications: A review

Sharon, Madhuri,Nandgavkar, Isaac,Sharon, Maheshwar Techno-Press 2017 Advances in materials research Vol.6 No.2

Platinum is a transition metal that is very resistant to corrosion. It is used as catalyst for converting methyl alcohol to formaldehyde, as catalytic converter in cars, for hydrocracking of heavy oils, in Fuel Cell devices etc. Moreover, Platinum compounds are important ingredient for cancer chemotherapy drugs. The nano forms of Platinum due to its unique physico-chemical properties that are not found in its bulk counterpart, has been found to be of great importance in electronics, optoelectronics, enzyme immobilization etc. The stability of Platinum nanoparticles has supported its use for the development of efficient and durable proton exchange membrane Fuel Cells. The present review concentrates on the use of Platinum conjugated with various metal or compounds, to fabricate nanocomposites, to enhance the efficiency of Platinum nanoparticles. The recent advances in the synthesis methods of different Platinum-based nanocomposites and their applications in Fuel Cell, sensors, bioimaging, light emitting diode, dye sensitized solar cell, hydrogen generation and in biosystems has also been discussed.

Laser Ablated Carbon Thin Film from Carbon Nanotubes and Their Property Studies

Maheshwar Sharon,M. Rusop,T. Soga,Rakesh A. Afre 한국탄소학회 2008 Carbon Letters Vol.9 No.1

A carbon nanotube (CNT) of diameter ~20 nm has been synthesized by spray pyrolysis of turpentine oil using Ni/Fe catalyst. Pellet of CNTs has been used as a target to produce semiconducting carbon thin film of band gap 1.4 eV. Presence of oxygen pressure in the pulse laser deposition (PLD) chamber helped to control the sp3/sp2 ratio to achieve the desired band gap. Results are discussed with the help of Raman spectra, SEM TEM micrographs and optical measurements suggest that semiconducting carbon thin film deposited by PLD technique has retained its nanotubes structure except that its diameter has increased from 20 nm to 150 nm.

Electrical and optical properties of semiconducting camphoric carbon films

Maheshwar Sharon,Debabrata Pradhan,Yoshinori Ando,Xinluo Zhao 한국물리학회 2002 Current Applied Physics Vol.2 No.6

In situ variation in resistance of camphoric carbon versus time of pyrolysis, temperature of pyrolysis and eect of sintering arestudied to perceive the time required for the completion of pyrolysis and the activation energy from the electrical conductance plot.Variation in the electrical conductance versus temperature and activation energies derived from these measurements, are repro-ducible when lm is thermally treated below 750.C. Thermal treatment above 750.change in the conductance prole as well as decreases its band gap to 0.1 eV. Camphor pyrolyzed at 650.C gives semiconductingcarbon with optical band gaps 1 eV (direct) and 0.8 eV (indirect). Increase in pyrolysis temperature also shifts G-band of Ramanspectrum from 1605 to 1586 cm. 1 i.e., towards value corresponding to graphitic carbon. SEM micrograph of camphoric lm showsabsence of any carbon nanobeads or bers as normally observed with camphoric carbon pyrolysed in this temperature range.

Laser Ablated Carbon Thin Film from Carbon Nanotubes and Their Property Studies

Sharon, Maheshwar,Rusop, M.,Soga, T.,Afre, Rakesh A. Korean Carbon Society 2008 Carbon Letters Vol.9 No.1

A carbon nanotube (CNT) of diameter ~20 nm has been synthesized by spray pyrolysis of turpentine oil using Ni/Fe catalyst. Pellet of CNTs has been used as a target to produce semiconducting carbon thin film of band gap 1.4 eV. Presence of oxygen pressure in the pulse laser deposition (PLD) chamber helped to control the $sp^3/sp^2$ ratio to achieve the desired band gap. Results are discussed with the help of Raman spectra, SEM TEM micrographs and optical measurements suggest that semiconducting carbon thin film deposited by PLD technique has retained its nanotubes structure except that its diameter has increased from 20 nm to 150 nm.

Effect of Inherent Anatomy of Plant Fibers on the Morphology of Carbon Synthesized from Them and Their Hydrogen Absorption Capacity

Madhuri Sharon,Maheshwar Sharon 한국탄소학회 2012 Carbon Letters Vol.13 No.3

Carbon materials were synthesized by pyrolysis from fibers of Corn-straw (Zea mays), Rice-straw (Oryza sativa), Jute-straw (Corchorus capsularis) Bamboo (Bombax bambusa), Bagass (Saccharum officinarum), Cotton (Bombax malabaricum), and Coconut (Cocos nucifera); these materials were characterized by scanning electron microscope, X-ray diffraction (XRD), and Raman spectra. All carbon materials are micro sized with large pores or channel like morphology. The unique complex spongy, porous and channel like structure of Carbon shows a lot of similarity with the original anatomy of the plant fibers used as precursor. Waxy contents like tyloses and pits present on fiber tracheids that were seen in the inherent anatomy disappear after pyrolysis and only the carbon skeleton remained; XRD analysis shows that carbon shows the development of a (002) plane, with the exception of carbon obtained from bamboo, which shows a very crystalline character. Raman studies of all carbon materials showed the presence of G- and D-bands of almost equal intensities, suggesting the presence of graphitic carbon as well as a disordered graphitic structure. Carbon materials possessing lesser density, larger surface area, more graphitic with less of an sp3 carbon contribution, and having pore sizes around 10μm favor hydrogen adsorption. Carbon materials synthesized from bagass meet these requirements most effectively, followed by cotton fiber, which was more effective than the carbon synthesized from the other plant fibers.

Carbon Material from Natural Sources as an Anode in Lithium Secondary Battery

Bhardwaj, Sunil,Sharon, Maheshwar,Ishihara, T.,Jayabhaye, Sandesh,Afre, Rakesh,Soga, T.,Sharon, Madhuri Korean Carbon Society 2007 Carbon Letters Vol.8 No.4

Carbon materials of various morphologies were synthesized by pyrolysis of Soap-nut seeds (Sapindus mukorossi), Jack Fruit seeds (Artocarpus heterophyllus), Date-seeds (Phoenix dactylifera), Neem seeds (Azadirachta indica), Tea leaves (Ehretia microphylla), Bamboo stem (Bambusa bambus) and Coconut fiber (Cocos nucifera), without using any catalyst. Carbon materials thus formed were characterized by SEM XRD and Raman. Carbon thus synthesized varied in size (in ${\mu}m$) but all showed highly porous morphology. These carbon materials were utilized as the anode in Lithium secondary battery. Amongst the various precursors, carbon fibers obtained from Soap-nut seeds (Sapindus mukorossi) and Bamboo stem (Bambusa bambus), even after $100^{th}$ cycles, showed the highest capacity of 130.29 mAh/g and 92.74 mAh/g respectively. Morphology, surface areas and porosity of carbon materials obtained from these precursors were analyzed to provide interpretation for their capacity to intercalate lithium. From the Raman studies it is concluded that graphitic nature of carbon materials assist in the intercalation of lithium. Size of cavity (or pore size of channels type structure) present in carbon materials were found to facilitate the intercalation of lithium.

Nanocarbon synthesis using plant oil and differential responses to various parameters optimized using the Taguchi method

Suman Tripathi,Maheshwar Sharon,N.N. Maldar,Jayashri Shukla,Madhuri Sharon 한국탄소학회 2013 Carbon Letters Vol.14 No.4

The synthesis of carbon nanomaterials (CNMs) by a chemical vapor deposition method using three different plant oils as precursors is presented. Because there are four param-eters involved in the synthesis of CNM (i.e., the precursor, reaction temperature of the furnace, catalysts, and the carrier gas), each having three variables, it was decided to use the Taguchi optimization method with the ‘the larger the better’ concept. The best parameter regarding the yield of carbon varied for each type of precursor oil. It was a temperature of 900°C + Ni as a catalyst for neem oil; 700°C + Co for karanja oil and 500°C + Zn as a catalyst for castor oil. The morphology of the nanocarbon produced was also impacted by different parameters. Neem oil and castor oil produced carbon nanotube (CNT) at 900°C; at lower temperatures, sphere-like structures developed. In contrast, karanja oil produced CNTs at all the assessed temperatures. X-ray diffraction and Raman diffraction analyses confirmedthat the nanocarbon (both carbon nano beads and CNTs) produced were graphitic in nature.

Taguchi optimization of the carbon anode for Li-ion battery from natural precursors

Sunil Bhardwaj,Maheshwar Sharon,T. Ishihara 한국물리학회 2008 Current Applied Physics Vol.8 No.1

Soya bean seed (Glysin maze), Baggas bers (Sacharum ocinarum) and Semer Cotton (Bombax ceiba) on pyrolysis give carbon nano-materials, which are tested for their application as anode in lithium ion batteries. Taguchi optimization technique is used to nd the bestnatural precursor, best temperature of the pyrolysis and the eect of pretreatment of acid and alkali to nd the best carbon for the elec-and pyrolysis at 700.C in an inert atmosphere of hydrogen favors the formation of carbon with best lithium intercalation properties.

Carbon Material from Natural Sources as an Anode in Lithium Secondary Battery

Sunil Bhardwaj,Maheshwar Sharon,T. Ishihara,Sandesh Jayabhaye,Rakesh Afre,T. Soga,Madhuri Sharon 한국탄소학회 2007 Carbon Letters Vol.8 No.4

Carbon materials of various morphologies were synthesized by pyrolysis of Soap-nut seeds (Sapindus mukorossi), Jack Fruit seeds (Artocarpus heterophyllus), Date-seeds (Phoenix dactylifera), Neem seeds (Azadirachta indica), Tea leaves (Ehretia microphylla), Bamboo stem (Bambusa bambus) and Coconut fiber (Cocos nucifera), without using any catalyst. Carbon materials thus formed were characterized by SEM XRD and Raman. Carbon thus synthesized varied in size (in μm) but all showed highly porous morphology. These carbon materials were utilized as the anode in Lithium secondary battery. Amongst the various precursors, carbon fibers obtained from Soap-nut seeds (Sapindus mukorossi) and Bamboo stem (Bambusa bambus), even after 100th cycles, showed the highest capacity of 130.29 mAh/g and 92.74 mAh/g respectively. Morphology, surface areas and porosity of carbon materials obtained from these precursors were analyzed to provide interpretation for their capacity to intercalate lithium. From the Raman studies it is concluded that graphitic nature of carbon materials assist in the intercalation of lithium. Size of cavity (or pore size of channels type structure) present in carbon materials were found to facilitate the intercalation of lithium.