Current lithium batteries operate on inorganic insertion compounds to power a diverse range of ap... more Current lithium batteries operate on inorganic insertion compounds to power a diverse range of applications, but recently there is a surging demand to develop environmentally friendly green electrode materials. To develop sustainable and eco-friendly lithium ion batteries, we report reversible lithium ion storage properties of a naturally occurring and abundant organic compound purpurin, which is non-toxic and derived from the plant madder. The carbonyl/hydroxyl groups present in purpurin molecules act as redox centers and reacts electrochemically with Li-ions during the charge/discharge process. The mechanism of lithiation of purpurin is fully elucidated using NMR, UV and FTIR spectral studies. The formation of the most favored six membered binding core of lithium ion with carbonyl groups of purpurin and hydroxyl groups at C-1 and C-4 positions respectively facilitated lithiation process, whereas hydroxyl group at C-2 position remains unaltered.
A modified version of the carburization process, a widely established technique used in the steel... more A modified version of the carburization process, a widely established technique used in the steel industry for case hardening of components, is used for the growth of graphene on stainless steel. Controlled growth of high-quality single- and few-layered graphene on stainless steel (SS) foils through a liquid-phase chemical vapor deposition (CVD) technique is reported. Reversible Li intercalation in these graphene-on-SS structures is demonstrated, where graphene and SS act as electrode and current collector, respectively, providing very good electrical contact. Direct growth of an active electrode material, such as graphene, on current-collector substrates makes this a feasible and efficient process for developing thin-film battery devices.
The paper presents a simple and inexpensive method for the preparation of an efficient hydrogen g... more The paper presents a simple and inexpensive method for the preparation of an efficient hydrogen gas sensor based on exfoliated Pd-decorated single-walled carbon nanotubes (SWNTs). SWNTs were synthesized by catalytic chemical vapor deposition of methane using a fixed-bed ...
A single-step approach for the synthesis of multi-walled nanotubes (MWNT) filled with nanowires o... more A single-step approach for the synthesis of multi-walled nanotubes (MWNT) filled with nanowires of Ni/ternary Zr based hydrogen storage alloy has been illustrated. We also demonstrate the generation of CO-free hydrogen by methane decomposition over alloy hydride catalyst. The present work also highlights the formation of single-walled nanotubes (SWNT) and MWNTs at varying process conditions. These carbon nanostructures have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), Energy dispersive X-ray analysis (EDX) and Raman spectroscopy. This new approach overcomes the existing multi-step process limitation, with possible impact on the development of future fuel cell, nano-battery and hydrogen sensor technologies.
Pressure?composition (P?C) hydrogen absorption isotherms have been obtained for MmNi3.5Al0.5Fe0.5... more Pressure?composition (P?C) hydrogen absorption isotherms have been obtained for MmNi3.5Al0.5Fe0.5Co0.5+0.5?wt%?B and MmNi3.5Al0.5Fe0.5Co0.5 +25?wt% polyaniline (PANI) in the ranges 30?100??C and 0.1?40?bar using a high pressure Seiverts' apparatus. The phase structure and microstructure morphologies of as-prepared and ball-milled materials have been analysed by XRD and SEM respectively. The effect of particle size, boron addition and PANI dispersion on the hydrogen absorption kinetics in MmNi3.5Al0.5Fe0.5Co0.5 has been studied and discussed. The diffusion coefficient and activation energy of dissolved hydrogen in MmNi3.5Al0.5Fe0.5Co0.5, MmNi3.5Al0.5Fe0.5Co0.5+0.5?wt%?B and MmNi3.5Al0.5Fe0.5Co0.5+25?wt%?PANI have been obtained from the studies of hydrogen absorption kinetics using the first order rate equation and the results have been discussed.
The present work describes the field emission properties of multi-walled nanotubes (MWNTs)-based ... more The present work describes the field emission properties of multi-walled nanotubes (MWNTs)-based conducting polymer/metal-oxide/metal/MWNTs composites (polyaniline (PANI)/SnO2/Sn/MWNTs). MWNTs were synthesised by chemical vapour deposition technique. SnO2/Sn/MWNTs were prepared by using chemical reduction followed by calcination. By in situ polymerisation method, surface of SnO2/Sn/MWNTs were coated with PANI. PANI/SnO2/Sn/MWNTs field emitters were fabricated over flexible graphitised carbon fabric substrate by spin
ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5 and boron added alloys have been prepared and dispersion of polyanil... more ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5 and boron added alloys have been prepared and dispersion of polyaniline (PANI) has been performed on ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B by ballmilling. Structural and micro-structural characterizations of these materials have been carried out by XRD and SEM, respectively. Hydrogen absorption pressure-composition (P-C) isotherms have been obtained for ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5, ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B and ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B + 25wt% PANI in the temperature and pressure ranges 30–100∘C and 0.1–30bar, respectively using a high-pressure Seiverts’ apparatus. The effect of particle size on the hydrogen absorption kinetics of ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5 and ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B alloys have been studied. From the hydrogen absorption kinetics, the activation energy of dissolved hydrogen in ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5 - H, (ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B) - H and (ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B + 25 wt% PANI) - H has been calculated and the results have been discussed.
Hydrogen absorption pressure-composition (PC) isotherms and kinetics of rhombohedral MmTM3 (TM=Ni... more Hydrogen absorption pressure-composition (PC) isotherms and kinetics of rhombohedral MmTM3 (TM=Ni, Fe and Co) alloys have been carried out using Sieverts type apparatus. The variations in plateau pressure, hydride stability and kinetics upon partial substitution of Fe or Co for Ni in MmNi3 have been discussed. The absorption kinetics have been analyzed based on the Johnson–Mehl–Avrami (JMA) model. The reaction
... composite, Int J Hydrogen Energy 33 (3) (2008), pp. 1028–1034. [14] A. Chambers, C. Park, RTK... more ... composite, Int J Hydrogen Energy 33 (3) (2008), pp. 1028–1034. [14] A. Chambers, C. Park, RTK Baker and NM Rodriguez, Hydrogen storage in graphite nanofibers, J Phys Chem B 102 (1998), pp. 4253–4256. Full Text via.
Current lithium batteries operate on inorganic insertion compounds to power a diverse range of ap... more Current lithium batteries operate on inorganic insertion compounds to power a diverse range of applications, but recently there is a surging demand to develop environmentally friendly green electrode materials. To develop sustainable and eco-friendly lithium ion batteries, we report reversible lithium ion storage properties of a naturally occurring and abundant organic compound purpurin, which is non-toxic and derived from the plant madder. The carbonyl/hydroxyl groups present in purpurin molecules act as redox centers and reacts electrochemically with Li-ions during the charge/discharge process. The mechanism of lithiation of purpurin is fully elucidated using NMR, UV and FTIR spectral studies. The formation of the most favored six membered binding core of lithium ion with carbonyl groups of purpurin and hydroxyl groups at C-1 and C-4 positions respectively facilitated lithiation process, whereas hydroxyl group at C-2 position remains unaltered.
A modified version of the carburization process, a widely established technique used in the steel... more A modified version of the carburization process, a widely established technique used in the steel industry for case hardening of components, is used for the growth of graphene on stainless steel. Controlled growth of high-quality single- and few-layered graphene on stainless steel (SS) foils through a liquid-phase chemical vapor deposition (CVD) technique is reported. Reversible Li intercalation in these graphene-on-SS structures is demonstrated, where graphene and SS act as electrode and current collector, respectively, providing very good electrical contact. Direct growth of an active electrode material, such as graphene, on current-collector substrates makes this a feasible and efficient process for developing thin-film battery devices.
The paper presents a simple and inexpensive method for the preparation of an efficient hydrogen g... more The paper presents a simple and inexpensive method for the preparation of an efficient hydrogen gas sensor based on exfoliated Pd-decorated single-walled carbon nanotubes (SWNTs). SWNTs were synthesized by catalytic chemical vapor deposition of methane using a fixed-bed ...
A single-step approach for the synthesis of multi-walled nanotubes (MWNT) filled with nanowires o... more A single-step approach for the synthesis of multi-walled nanotubes (MWNT) filled with nanowires of Ni/ternary Zr based hydrogen storage alloy has been illustrated. We also demonstrate the generation of CO-free hydrogen by methane decomposition over alloy hydride catalyst. The present work also highlights the formation of single-walled nanotubes (SWNT) and MWNTs at varying process conditions. These carbon nanostructures have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), Energy dispersive X-ray analysis (EDX) and Raman spectroscopy. This new approach overcomes the existing multi-step process limitation, with possible impact on the development of future fuel cell, nano-battery and hydrogen sensor technologies.
Pressure?composition (P?C) hydrogen absorption isotherms have been obtained for MmNi3.5Al0.5Fe0.5... more Pressure?composition (P?C) hydrogen absorption isotherms have been obtained for MmNi3.5Al0.5Fe0.5Co0.5+0.5?wt%?B and MmNi3.5Al0.5Fe0.5Co0.5 +25?wt% polyaniline (PANI) in the ranges 30?100??C and 0.1?40?bar using a high pressure Seiverts' apparatus. The phase structure and microstructure morphologies of as-prepared and ball-milled materials have been analysed by XRD and SEM respectively. The effect of particle size, boron addition and PANI dispersion on the hydrogen absorption kinetics in MmNi3.5Al0.5Fe0.5Co0.5 has been studied and discussed. The diffusion coefficient and activation energy of dissolved hydrogen in MmNi3.5Al0.5Fe0.5Co0.5, MmNi3.5Al0.5Fe0.5Co0.5+0.5?wt%?B and MmNi3.5Al0.5Fe0.5Co0.5+25?wt%?PANI have been obtained from the studies of hydrogen absorption kinetics using the first order rate equation and the results have been discussed.
The present work describes the field emission properties of multi-walled nanotubes (MWNTs)-based ... more The present work describes the field emission properties of multi-walled nanotubes (MWNTs)-based conducting polymer/metal-oxide/metal/MWNTs composites (polyaniline (PANI)/SnO2/Sn/MWNTs). MWNTs were synthesised by chemical vapour deposition technique. SnO2/Sn/MWNTs were prepared by using chemical reduction followed by calcination. By in situ polymerisation method, surface of SnO2/Sn/MWNTs were coated with PANI. PANI/SnO2/Sn/MWNTs field emitters were fabricated over flexible graphitised carbon fabric substrate by spin
ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5 and boron added alloys have been prepared and dispersion of polyanil... more ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5 and boron added alloys have been prepared and dispersion of polyaniline (PANI) has been performed on ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B by ballmilling. Structural and micro-structural characterizations of these materials have been carried out by XRD and SEM, respectively. Hydrogen absorption pressure-composition (P-C) isotherms have been obtained for ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5, ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B and ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B + 25wt% PANI in the temperature and pressure ranges 30–100∘C and 0.1–30bar, respectively using a high-pressure Seiverts’ apparatus. The effect of particle size on the hydrogen absorption kinetics of ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5 and ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B alloys have been studied. From the hydrogen absorption kinetics, the activation energy of dissolved hydrogen in ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5 - H, (ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B) - H and (ZrMn0.85Cr0.1V0.05Fe0.5Ni0.5+1wt% B + 25 wt% PANI) - H has been calculated and the results have been discussed.
Hydrogen absorption pressure-composition (PC) isotherms and kinetics of rhombohedral MmTM3 (TM=Ni... more Hydrogen absorption pressure-composition (PC) isotherms and kinetics of rhombohedral MmTM3 (TM=Ni, Fe and Co) alloys have been carried out using Sieverts type apparatus. The variations in plateau pressure, hydride stability and kinetics upon partial substitution of Fe or Co for Ni in MmNi3 have been discussed. The absorption kinetics have been analyzed based on the Johnson–Mehl–Avrami (JMA) model. The reaction
... composite, Int J Hydrogen Energy 33 (3) (2008), pp. 1028–1034. [14] A. Chambers, C. Park, RTK... more ... composite, Int J Hydrogen Energy 33 (3) (2008), pp. 1028–1034. [14] A. Chambers, C. Park, RTK Baker and NM Rodriguez, Hydrogen storage in graphite nanofibers, J Phys Chem B 102 (1998), pp. 4253–4256. Full Text via.
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