Maheshwar Sharon - Academia.edu (original) (raw)

Papers by Maheshwar Sharon

Research paper thumbnail of An AC drive system for a battery driven moped

Proceedings of International Conference on Power Electronics, Drives and Energy Systems for Industrial Growth

ABSTRACT

Research paper thumbnail of A New Carbon Material Synthesized from Coconut Shell

Advanced Science, Engineering and Medicine, 2011

... Acknowledgments: The authors would like to thank Dr. Vijay Jadhav and Mr. MG Patil, Head, Dep... more ... Acknowledgments: The authors would like to thank Dr. Vijay Jadhav and Mr. MG Patil, Head, Department of Physics for valuable discussion. The authors would also like to thank Principal, Dr. Naresh Chandra and manage-ment authorities of Birla College, Kalyan for their ...

Research paper thumbnail of A study of the electrical properties of SbSI synthesized using CVD techniques

QScience Connect, 2013

Rod-shaped antimony sulphoiodide (SbSI) crystals were grown by utilizing elemental components of ... more Rod-shaped antimony sulphoiodide (SbSI) crystals were grown by utilizing elemental components of the compound. The material was characterized by X-ray diffraction (XRD), Raman and surface morphology by SEM. Electrical conductivity was measured on the pallets of powdered SbSI by the four-probe technique in the temperature range of 4-300K, and by the two-probe technique in the temperature range of 300-550K. SbSI shows semiconducting behavior in the temperature range of 300-550K and metallic below 300K. Activation energy of an electrical conduction between 300-550K, is 1.87 eV.

Research paper thumbnail of Study of electrochemical and photoelectrochemical properties of nickel phosphide semiconductors

Solar Cells, 1989

For the first time a detailed photoelectrochemical study of n-type nickel phosphide (Ni2P) materi... more For the first time a detailed photoelectrochemical study of n-type nickel phosphide (Ni2P) material (thin film as well as powder) is reported. This material has a hexagonal structure with a band,gap of 1.0 eV. The band edge positions are calculated using electron spectroscopy for chemical analysis. The compound is found to be stable in alkaline and acidic media. The photoconversion efficiency is found to be 0.26%.

Research paper thumbnail of Superconductivity and valence state of Tl in TlA2-xLaxCuO5 and TlA2Ca1-xGdxCu2O7 (A=Ba,Sr)

Our x-ray core-level spectroscopic measurements show that the valence state of Tl in Ba containin... more Our x-ray core-level spectroscopic measurements show that the valence state of Tl in Ba containing single-Tl-0-layered compounds T1Baz "La"Cu05 and T1BazCal "Gd"CuzO, is +3 whereas in Sr containing single-Tl-0-layered comPounds T1Srz La"CuO, and T1SrzCal, Gd"Cuz07 is between +3 and + 1. The origin of holes in the latter is discussed in terms of charge transfer between the Tl 6s band and the Cu 3d z z band in addition to the holes generated due to excess oxygen. This is in contrast to the xy former wherein the origin of the holes is due to the excess of oxygen only.

Research paper thumbnail of Photoelectrochemical studies of BaTiO3 electrolyte redox systems

Solar Energy Materials, 1984

n-BaTiO 3 (doped with lanthanum) has been prepared by the alkoxy method. It has been found that t... more n-BaTiO 3 (doped with lanthanum) has been prepared by the alkoxy method. It has been found that this method requires a sintering temperature lower than 1450°C (i.e. ll00°C). The band-gap of the material is found to be 3.19 eV. It is observed that Vtb does not depend upon the electrolyte, with the exception of KI and Fe(Cn)64-ions. Band bending is observed to show the dependence over E~do~ of the electrolytes. The donor level and the space charge region have been calculated. It is observed that the position of the conduction band-edge depends upon the nature of the electrolyte, making the contact with BaTiO3; suggesting that the metal-semiconductor model of Mott-Schottky is not strictly applicable to the semiconductor-electrolyte system. Finally, it is suggested that BaTiO 3 is stable against chemical corrosion in acidic medium or if corroding, its rate of corrosion is too slow to be noticed in two weeks.

Research paper thumbnail of Photovoltaic solar cell from camphoric carbon A natural source

Solar Energy Materials and Solar Cells, 1997

Thin films of camphoric carbon, a natural source, have been deposited on a single crystal Si (1 0... more Thin films of camphoric carbon, a natural source, have been deposited on a single crystal Si (1 0 0) surface, 2° off towards[0 1 1] and quartz/glass substrates, at room temperature, by both electron and ion beam deposition. The crystal structure, composition analysis, surface morphology and other optical properties of these films have been studied using X-ray diffraction (XRD), X-ray

Research paper thumbnail of Saur Viddyut Kosh IV: Study of a rechargeable solar battery with n-Pb3O4 electrodes

Solar Cells, 1984

The semiconductor n-PbsO4 (Eg ffi 2.1 eV) was prepared by the citrate method, and the conversion ... more The semiconductor n-PbsO4 (Eg ffi 2.1 eV) was prepared by the citrate method, and the conversion efficiency of the photoelectrochemical cell n-Pb304]Fe 3+, Fe2+lPt was found to be 0.09%. A Saur Viddyut Kosh (rechargeable solar battery) of the following type was then prepared: n-Pb304, PtIFe 3+ (10-1 M), Fe 2+ (saturated)llIO3-(10-1 M), I-(10-1 M)IPt The dark potential of the charged battery was 0.84 V; the charging efficiency of the battery was 72%. The energy diagram of n-Pb304 calculated from the experimentally determined fiat-band potential V~b (-0.31 V measured with respect to a standard calomel electrode) was found to differ from the values calculated by the Butler-Ginley method. The Pb304 electrode appears to corrode photoelectrochemicaUy. However, when a saturated solution of Fe 2+ was used, the rate of corrosion appeared to slow down.

Research paper thumbnail of Carbon Nanomaterial Shows Drug Delivery Promise: Part 1—Selection of Carbon Nanomaterial and Drug Loading

Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 2006

... 15533170500478792 Seema Parihar a * , Maheshwar Sharon a & Madhuri Sharon b pages 107... more ... 15533170500478792 Seema Parihar a * , Maheshwar Sharon a & Madhuri Sharon b pages 107-113. ... Thanks are due to Dr Naresh Chandra, Principal Birla College and my colleagues of Chemistry department and Nanotech Research Lab for providing the necessary support. ...

Research paper thumbnail of Study of Hydrogen Adsorption by Spiral Carbon Nano Fibers Synthesized From Acetylene

Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 2006

... Grow carbon fiber in vapor phase. Chemtech., : 568–576. 9. Snyder, CE, Mandeville, WH, Tennen... more ... Grow carbon fiber in vapor phase. Chemtech., : 568–576. 9. Snyder, CE, Mandeville, WH, Tennent, HG and Truesdale, LK US Patent . 1989. 10. Baker, RT and Rodriguez, NM 1994. Symp. Mater. Res. Soc., 349: 125; 11. Jaybhaye, SV, Sharon, M. and Kshirsagar, DE 2005. ...

Research paper thumbnail of Hydrogenated amorphous carbon based solar cells by pulsed laser deposition with mixture of graphite and camphor as precursor materials

Surface Engineering, 2007

The authors have deposited hydrogenated amorphous carbon films (a-C:H) on quartz and p type silic... more The authors have deposited hydrogenated amorphous carbon films (a-C:H) on quartz and p type silicon substrates (100) by pulsed laser deposition (PLD) using a mixture of graphite and camphor powders at room temperature. The presence of hydrogen in the a-C:H films has been revealed by fourier transform infrared spectroscopy (FTIR) measurement. The solar cell structure of a-C:H/p-Si was also fabricated. The formation of a heterojunction between the a-C:H films and silicon substrate was confirmed by the current-voltage (I-V) measurement in the dark and under illumination conditions. The structure of a-C:H/p-Si showed photovoltaic characteristics with an open circuit voltage Voc of 400 mV and short circuit current density Jsc of ~15 mA cm-2 under illumination [air mass (AM) 1•5, 100 mW cm-2, 25°C]. From the calculation, the energy conversion efficiency and fill factor were found to be approximately 2•1% and 0•38 respectively. The carbon layer is contributed to the energy conversion efficiency, which was proved by the measurement of quantum efficiency.

Research paper thumbnail of Studies of the superconducting behaviour of TlBa2−xLaxCuO5−y

Physica C: Superconductivity, 1991

The superconducting behaviour of the system T1Ba2_xLaxCuOs_~ has been investigated. Samples prepa... more The superconducting behaviour of the system T1Ba2_xLaxCuOs_~ has been investigated. Samples prepared by the procedure described in this paper show a decrease in Tc with increasing lanthanum concentration. This is in contrast to the trend reported by other authors [ 15,19 ]. This difference in behaviour was explained in terms of the oxygen deficiency y in the parent compound T1Ba2CuO5 y.

Research paper thumbnail of Carbon nanotubes from camphor by catalytic cvd

Molecular Crystals and Liquid Crystals, 2002

Multi-wall carbon nanotubes (MWNTs) have been grown from simple pyrolysis of camphor, a botanical... more Multi-wall carbon nanotubes (MWNTs) have been grown from simple pyrolysis of camphor, a botanical hydrocarbon, at 900°C for 15 min in argon atmosphere at ambient pressure using ferrocene as a catalyst. The nanotube diameter is fairly uniform (20-40 nm) and the yield is ...

Research paper thumbnail of Nano-Range Octopus Type Vapor Grown Carbon Fibers from Camphor

Molecular Crystals and Liquid Crystals, 2002

Carbon nanofibers are synthesised by pyrolysis of camphor vapor in nitrogen atmosphere in the tem... more Carbon nanofibers are synthesised by pyrolysis of camphor vapor in nitrogen atmosphere in the temperature range of 650°C to 750°C. Thickness of carbon fibers increases from 30 nm to 250 nm with an increase of pyrolysis temperature. Characterizations of these fibers were ...

Research paper thumbnail of Synthesis of conducting fibers, nanotubes, and thin films of carbon from commercial kerosene

Materials Research Bulletin, 1999

Commercial kerosene, commonly used as a cheap fuel for cooking or lighting in underdeveloped area... more Commercial kerosene, commonly used as a cheap fuel for cooking or lighting in underdeveloped areas, has for the first time been found capable of producing conducting fibers, nanotubes, and thin films of carbon. The process of synthesis involves simple pyrolysis of kerosene vapor at 1000°C in argon atmosphere. Various kinds of conducting fibers were obtained, viz., 6-7-cmlong straight fibers (70-75 m), flexible hair-like fibers (2 m), soft wool-like fibers (60-250 nm), tiny earthworm-like fibers (50 nm), rough bitter-gourd-like fibers (3 m), and uniform hollow fibers (nanotubes of inner and outer diameters of 30 and 80 nm, respectively). Formation of these kerosene-pyrolyzed products and their interrelation are discussed on the basis of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies. X-ray diffraction (XRD) analyses of these nanocarbon materials suggest that they have a novel structure, not matching that of known forms of carbon. This conclusion is supported by FTIR and laser-Raman analyses. Thin film of conducting carbon was found to possess an electrochemical potential window as wide as 2.91 V and was effectively used to electrolyze 30% brine solution at a current density of 300 mA cm Ϫ2 at 3 V. It is suggested that the kerosene-pyrolyzed carbon electrodes can be used in the chloro-alkali industry.

Research paper thumbnail of Effect of pyrolyzing time and temperature on the bandgap of camphor-pyrolyzed semiconducting carbon films

Materials Chemistry and Physics, 1998

Intrinsic p-and n-type semicondacting carbon thin films have been synthesized by the pyrolysis of... more Intrinsic p-and n-type semicondacting carbon thin films have been synthesized by the pyrolysis of camphor vapor in an argon atmosphere at various temperatures for different periods of time. These films are characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM) analyses, Hall measurement and electrical conductivity studies. The nature of conductivity of camphor-pyrolyzed semiconductors is found to be extremely sensitive to the pyrolyzing temperature and time. It is observed that an sp 2 content in the as-grown film of less than 33% yields a p-type semiconductor, whereas more than 33% sp °-makes it n-type. The percentage contents of sp 2 and sp 3 carbon can be controlled by the temperature and time of pyrolysis.

Research paper thumbnail of Preparation and characterization of TiO2/Fe2O3 binary mixed oxides and its photocatalytic properties

Materials Chemistry and Physics, 1999

О фотокаталитической активности систем типа диоксид титана/Fe(II, III) в водных суспензиях Кандид... more О фотокаталитической активности систем типа диоксид титана/Fe(II, III) в водных суспензиях Кандидаты хим. наук, доценты В. А. Горбунова 1) , Л. М. Слепнева 1) 1) Белорусский национальный технический университет (Минск, Республика Беларусь)

Research paper thumbnail of Taguchi method optimization of wax production from pyrolysis of waste polypropylene

Journal of Thermal Analysis and Calorimetry, 2014

ABSTRACT Present research deals with the conversion of waste commodity plastics to valuable comme... more ABSTRACT Present research deals with the conversion of waste commodity plastics to valuable commercial product in the form of wax by pyrolysis. Optimization of both processes yield and produced wax quality was performed by means of a statistical tool originally proposed by G. Taguchi, using temperature, catalyst, carrier gas, and dwell time as the parameters. The obtained wax was characterized by Raman spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Yield of wax was found to be maximum when the parameters were 600�C, Fe catalyst, nitrogen gas atmosphere, and 15 min time. However, stability of the wax was found to be optimum at 700�C. Calorific value of the wax thus obtained was*43 MJ kg -1 , which supports its suitability as fuels like other petroleum products.

Research paper thumbnail of Effect of platinum on the photoelectrochemical behavior of lead oxide thin film

Journal of Solid State Electrochemistry, 1998

The eect of Pt on the photoelectrochemical behavior of lead oxide prepared from anodization of Pb... more The eect of Pt on the photoelectrochemical behavior of lead oxide prepared from anodization of Pb-Pt alloy containing various concentrations of Pt has been studied. It is observed that, while Pt reduces the resistivity of the oxide ®lm, it also reduces the photoconversion eciency of the photoelectrochemical cell prepared from this material. The reason for this low eciency is discussed.

Research paper thumbnail of Synthesis of vapor-grown carbon fibers from camphor without catalyst and their characterization

Journal of Materials Research, 2003

Vapor-grown carbon fibers and carbon micro-beads were produced in the absence of catalysts from a... more Vapor-grown carbon fibers and carbon micro-beads were produced in the absence of catalysts from a natural precursor, camphor, by a thermal chemical vapor deposition process, at different temperatures in an argon medium. Scanning and transmission electron microscopy, Raman spectra, and electrical conductivity studies were used to characterize these fibers. It was observed that cylindrical fibers (diameter ∼3 μm) were obtained at 1033 K and rippled fibers (diameter ∼5 μm) were formed at 1273 K while carbon beads (diameter ∼0.5–1 μm) were formed at 1173 K. It is proposed that agglomeration of carbon beads predominate at pyrolysis temperature greater than 1173 K, resulting into rippled type fibers.

Research paper thumbnail of An AC drive system for a battery driven moped

Proceedings of International Conference on Power Electronics, Drives and Energy Systems for Industrial Growth

ABSTRACT

Research paper thumbnail of A New Carbon Material Synthesized from Coconut Shell

Advanced Science, Engineering and Medicine, 2011

... Acknowledgments: The authors would like to thank Dr. Vijay Jadhav and Mr. MG Patil, Head, Dep... more ... Acknowledgments: The authors would like to thank Dr. Vijay Jadhav and Mr. MG Patil, Head, Department of Physics for valuable discussion. The authors would also like to thank Principal, Dr. Naresh Chandra and manage-ment authorities of Birla College, Kalyan for their ...

Research paper thumbnail of A study of the electrical properties of SbSI synthesized using CVD techniques

QScience Connect, 2013

Rod-shaped antimony sulphoiodide (SbSI) crystals were grown by utilizing elemental components of ... more Rod-shaped antimony sulphoiodide (SbSI) crystals were grown by utilizing elemental components of the compound. The material was characterized by X-ray diffraction (XRD), Raman and surface morphology by SEM. Electrical conductivity was measured on the pallets of powdered SbSI by the four-probe technique in the temperature range of 4-300K, and by the two-probe technique in the temperature range of 300-550K. SbSI shows semiconducting behavior in the temperature range of 300-550K and metallic below 300K. Activation energy of an electrical conduction between 300-550K, is 1.87 eV.

Research paper thumbnail of Study of electrochemical and photoelectrochemical properties of nickel phosphide semiconductors

Solar Cells, 1989

For the first time a detailed photoelectrochemical study of n-type nickel phosphide (Ni2P) materi... more For the first time a detailed photoelectrochemical study of n-type nickel phosphide (Ni2P) material (thin film as well as powder) is reported. This material has a hexagonal structure with a band,gap of 1.0 eV. The band edge positions are calculated using electron spectroscopy for chemical analysis. The compound is found to be stable in alkaline and acidic media. The photoconversion efficiency is found to be 0.26%.

Research paper thumbnail of Superconductivity and valence state of Tl in TlA2-xLaxCuO5 and TlA2Ca1-xGdxCu2O7 (A=Ba,Sr)

Our x-ray core-level spectroscopic measurements show that the valence state of Tl in Ba containin... more Our x-ray core-level spectroscopic measurements show that the valence state of Tl in Ba containing single-Tl-0-layered compounds T1Baz "La"Cu05 and T1BazCal "Gd"CuzO, is +3 whereas in Sr containing single-Tl-0-layered comPounds T1Srz La"CuO, and T1SrzCal, Gd"Cuz07 is between +3 and + 1. The origin of holes in the latter is discussed in terms of charge transfer between the Tl 6s band and the Cu 3d z z band in addition to the holes generated due to excess oxygen. This is in contrast to the xy former wherein the origin of the holes is due to the excess of oxygen only.

Research paper thumbnail of Photoelectrochemical studies of BaTiO3 electrolyte redox systems

Solar Energy Materials, 1984

n-BaTiO 3 (doped with lanthanum) has been prepared by the alkoxy method. It has been found that t... more n-BaTiO 3 (doped with lanthanum) has been prepared by the alkoxy method. It has been found that this method requires a sintering temperature lower than 1450°C (i.e. ll00°C). The band-gap of the material is found to be 3.19 eV. It is observed that Vtb does not depend upon the electrolyte, with the exception of KI and Fe(Cn)64-ions. Band bending is observed to show the dependence over E~do~ of the electrolytes. The donor level and the space charge region have been calculated. It is observed that the position of the conduction band-edge depends upon the nature of the electrolyte, making the contact with BaTiO3; suggesting that the metal-semiconductor model of Mott-Schottky is not strictly applicable to the semiconductor-electrolyte system. Finally, it is suggested that BaTiO 3 is stable against chemical corrosion in acidic medium or if corroding, its rate of corrosion is too slow to be noticed in two weeks.

Research paper thumbnail of Photovoltaic solar cell from camphoric carbon A natural source

Solar Energy Materials and Solar Cells, 1997

Thin films of camphoric carbon, a natural source, have been deposited on a single crystal Si (1 0... more Thin films of camphoric carbon, a natural source, have been deposited on a single crystal Si (1 0 0) surface, 2° off towards[0 1 1] and quartz/glass substrates, at room temperature, by both electron and ion beam deposition. The crystal structure, composition analysis, surface morphology and other optical properties of these films have been studied using X-ray diffraction (XRD), X-ray

Research paper thumbnail of Saur Viddyut Kosh IV: Study of a rechargeable solar battery with n-Pb3O4 electrodes

Solar Cells, 1984

The semiconductor n-PbsO4 (Eg ffi 2.1 eV) was prepared by the citrate method, and the conversion ... more The semiconductor n-PbsO4 (Eg ffi 2.1 eV) was prepared by the citrate method, and the conversion efficiency of the photoelectrochemical cell n-Pb304]Fe 3+, Fe2+lPt was found to be 0.09%. A Saur Viddyut Kosh (rechargeable solar battery) of the following type was then prepared: n-Pb304, PtIFe 3+ (10-1 M), Fe 2+ (saturated)llIO3-(10-1 M), I-(10-1 M)IPt The dark potential of the charged battery was 0.84 V; the charging efficiency of the battery was 72%. The energy diagram of n-Pb304 calculated from the experimentally determined fiat-band potential V~b (-0.31 V measured with respect to a standard calomel electrode) was found to differ from the values calculated by the Butler-Ginley method. The Pb304 electrode appears to corrode photoelectrochemicaUy. However, when a saturated solution of Fe 2+ was used, the rate of corrosion appeared to slow down.

Research paper thumbnail of Carbon Nanomaterial Shows Drug Delivery Promise: Part 1—Selection of Carbon Nanomaterial and Drug Loading

Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 2006

... 15533170500478792 Seema Parihar a * , Maheshwar Sharon a & Madhuri Sharon b pages 107... more ... 15533170500478792 Seema Parihar a * , Maheshwar Sharon a & Madhuri Sharon b pages 107-113. ... Thanks are due to Dr Naresh Chandra, Principal Birla College and my colleagues of Chemistry department and Nanotech Research Lab for providing the necessary support. ...

Research paper thumbnail of Study of Hydrogen Adsorption by Spiral Carbon Nano Fibers Synthesized From Acetylene

Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 2006

... Grow carbon fiber in vapor phase. Chemtech., : 568–576. 9. Snyder, CE, Mandeville, WH, Tennen... more ... Grow carbon fiber in vapor phase. Chemtech., : 568–576. 9. Snyder, CE, Mandeville, WH, Tennent, HG and Truesdale, LK US Patent . 1989. 10. Baker, RT and Rodriguez, NM 1994. Symp. Mater. Res. Soc., 349: 125; 11. Jaybhaye, SV, Sharon, M. and Kshirsagar, DE 2005. ...

Research paper thumbnail of Hydrogenated amorphous carbon based solar cells by pulsed laser deposition with mixture of graphite and camphor as precursor materials

Surface Engineering, 2007

The authors have deposited hydrogenated amorphous carbon films (a-C:H) on quartz and p type silic... more The authors have deposited hydrogenated amorphous carbon films (a-C:H) on quartz and p type silicon substrates (100) by pulsed laser deposition (PLD) using a mixture of graphite and camphor powders at room temperature. The presence of hydrogen in the a-C:H films has been revealed by fourier transform infrared spectroscopy (FTIR) measurement. The solar cell structure of a-C:H/p-Si was also fabricated. The formation of a heterojunction between the a-C:H films and silicon substrate was confirmed by the current-voltage (I-V) measurement in the dark and under illumination conditions. The structure of a-C:H/p-Si showed photovoltaic characteristics with an open circuit voltage Voc of 400 mV and short circuit current density Jsc of ~15 mA cm-2 under illumination [air mass (AM) 1•5, 100 mW cm-2, 25°C]. From the calculation, the energy conversion efficiency and fill factor were found to be approximately 2•1% and 0•38 respectively. The carbon layer is contributed to the energy conversion efficiency, which was proved by the measurement of quantum efficiency.

Research paper thumbnail of Studies of the superconducting behaviour of TlBa2−xLaxCuO5−y

Physica C: Superconductivity, 1991

The superconducting behaviour of the system T1Ba2_xLaxCuOs_~ has been investigated. Samples prepa... more The superconducting behaviour of the system T1Ba2_xLaxCuOs_~ has been investigated. Samples prepared by the procedure described in this paper show a decrease in Tc with increasing lanthanum concentration. This is in contrast to the trend reported by other authors [ 15,19 ]. This difference in behaviour was explained in terms of the oxygen deficiency y in the parent compound T1Ba2CuO5 y.

Research paper thumbnail of Carbon nanotubes from camphor by catalytic cvd

Molecular Crystals and Liquid Crystals, 2002

Multi-wall carbon nanotubes (MWNTs) have been grown from simple pyrolysis of camphor, a botanical... more Multi-wall carbon nanotubes (MWNTs) have been grown from simple pyrolysis of camphor, a botanical hydrocarbon, at 900°C for 15 min in argon atmosphere at ambient pressure using ferrocene as a catalyst. The nanotube diameter is fairly uniform (20-40 nm) and the yield is ...

Research paper thumbnail of Nano-Range Octopus Type Vapor Grown Carbon Fibers from Camphor

Molecular Crystals and Liquid Crystals, 2002

Carbon nanofibers are synthesised by pyrolysis of camphor vapor in nitrogen atmosphere in the tem... more Carbon nanofibers are synthesised by pyrolysis of camphor vapor in nitrogen atmosphere in the temperature range of 650°C to 750°C. Thickness of carbon fibers increases from 30 nm to 250 nm with an increase of pyrolysis temperature. Characterizations of these fibers were ...

Research paper thumbnail of Synthesis of conducting fibers, nanotubes, and thin films of carbon from commercial kerosene

Materials Research Bulletin, 1999

Commercial kerosene, commonly used as a cheap fuel for cooking or lighting in underdeveloped area... more Commercial kerosene, commonly used as a cheap fuel for cooking or lighting in underdeveloped areas, has for the first time been found capable of producing conducting fibers, nanotubes, and thin films of carbon. The process of synthesis involves simple pyrolysis of kerosene vapor at 1000°C in argon atmosphere. Various kinds of conducting fibers were obtained, viz., 6-7-cmlong straight fibers (70-75 m), flexible hair-like fibers (2 m), soft wool-like fibers (60-250 nm), tiny earthworm-like fibers (50 nm), rough bitter-gourd-like fibers (3 m), and uniform hollow fibers (nanotubes of inner and outer diameters of 30 and 80 nm, respectively). Formation of these kerosene-pyrolyzed products and their interrelation are discussed on the basis of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies. X-ray diffraction (XRD) analyses of these nanocarbon materials suggest that they have a novel structure, not matching that of known forms of carbon. This conclusion is supported by FTIR and laser-Raman analyses. Thin film of conducting carbon was found to possess an electrochemical potential window as wide as 2.91 V and was effectively used to electrolyze 30% brine solution at a current density of 300 mA cm Ϫ2 at 3 V. It is suggested that the kerosene-pyrolyzed carbon electrodes can be used in the chloro-alkali industry.

Research paper thumbnail of Effect of pyrolyzing time and temperature on the bandgap of camphor-pyrolyzed semiconducting carbon films

Materials Chemistry and Physics, 1998

Intrinsic p-and n-type semicondacting carbon thin films have been synthesized by the pyrolysis of... more Intrinsic p-and n-type semicondacting carbon thin films have been synthesized by the pyrolysis of camphor vapor in an argon atmosphere at various temperatures for different periods of time. These films are characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM) analyses, Hall measurement and electrical conductivity studies. The nature of conductivity of camphor-pyrolyzed semiconductors is found to be extremely sensitive to the pyrolyzing temperature and time. It is observed that an sp 2 content in the as-grown film of less than 33% yields a p-type semiconductor, whereas more than 33% sp °-makes it n-type. The percentage contents of sp 2 and sp 3 carbon can be controlled by the temperature and time of pyrolysis.

Research paper thumbnail of Preparation and characterization of TiO2/Fe2O3 binary mixed oxides and its photocatalytic properties

Materials Chemistry and Physics, 1999

О фотокаталитической активности систем типа диоксид титана/Fe(II, III) в водных суспензиях Кандид... more О фотокаталитической активности систем типа диоксид титана/Fe(II, III) в водных суспензиях Кандидаты хим. наук, доценты В. А. Горбунова 1) , Л. М. Слепнева 1) 1) Белорусский национальный технический университет (Минск, Республика Беларусь)

Research paper thumbnail of Taguchi method optimization of wax production from pyrolysis of waste polypropylene

Journal of Thermal Analysis and Calorimetry, 2014

ABSTRACT Present research deals with the conversion of waste commodity plastics to valuable comme... more ABSTRACT Present research deals with the conversion of waste commodity plastics to valuable commercial product in the form of wax by pyrolysis. Optimization of both processes yield and produced wax quality was performed by means of a statistical tool originally proposed by G. Taguchi, using temperature, catalyst, carrier gas, and dwell time as the parameters. The obtained wax was characterized by Raman spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Yield of wax was found to be maximum when the parameters were 600�C, Fe catalyst, nitrogen gas atmosphere, and 15 min time. However, stability of the wax was found to be optimum at 700�C. Calorific value of the wax thus obtained was*43 MJ kg -1 , which supports its suitability as fuels like other petroleum products.

Research paper thumbnail of Effect of platinum on the photoelectrochemical behavior of lead oxide thin film

Journal of Solid State Electrochemistry, 1998

The eect of Pt on the photoelectrochemical behavior of lead oxide prepared from anodization of Pb... more The eect of Pt on the photoelectrochemical behavior of lead oxide prepared from anodization of Pb-Pt alloy containing various concentrations of Pt has been studied. It is observed that, while Pt reduces the resistivity of the oxide ®lm, it also reduces the photoconversion eciency of the photoelectrochemical cell prepared from this material. The reason for this low eciency is discussed.

Research paper thumbnail of Synthesis of vapor-grown carbon fibers from camphor without catalyst and their characterization

Journal of Materials Research, 2003

Vapor-grown carbon fibers and carbon micro-beads were produced in the absence of catalysts from a... more Vapor-grown carbon fibers and carbon micro-beads were produced in the absence of catalysts from a natural precursor, camphor, by a thermal chemical vapor deposition process, at different temperatures in an argon medium. Scanning and transmission electron microscopy, Raman spectra, and electrical conductivity studies were used to characterize these fibers. It was observed that cylindrical fibers (diameter ∼3 μm) were obtained at 1033 K and rippled fibers (diameter ∼5 μm) were formed at 1273 K while carbon beads (diameter ∼0.5–1 μm) were formed at 1173 K. It is proposed that agglomeration of carbon beads predominate at pyrolysis temperature greater than 1173 K, resulting into rippled type fibers.