S. Zahra Mortazavi | AmirKabir University Of Technology (original) (raw)
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Papers by S. Zahra Mortazavi
Hydrogen Storage in Decorated Multiwalled Carbon Nanotubes by Ca, Co, Fe, Ni, and Pd Nanoparticles under Ambient Conditions
We report a study on hydrogen storage in Ca, Co, Fe, Ni, and Pd decorated multiwalled carbon nano... more We report a study on hydrogen storage in Ca, Co, Fe, Ni, and Pd decorated multiwalled carbon nanotubes (MWCNTs) by using two techniques: volumetric and electrochemical. The results showed that hydrogen molecules are adsorbed on the defect sites and transported to the ...
The Journal of Physical Chemistry C, 2014
Methane decomposition has been extensively investigated using a Q-switched Nd:YAG laser, focused ... more Methane decomposition has been extensively investigated using a
Q-switched Nd:YAG laser, focused on the metal catalysts including Ni, Fe, Pd, and Cu within the controlled chamber to verify the effect of catalyst, plasma properties, and yield and selectivity of the products. Fourier transform IR spectroscopy (FTIR) and gas chromatography (GC) are employed to support the characterization of the components. This indicates that methane is strongly decomposed within the metal-assisted laser-induced plasma, leading to the subsequent recombination and the production of heavier hydrocarbons. The dominant species, including propane, ethane, and ethylene, have been identified examining different metallic catalysts. The dissociation rate, conversion ratio, selectivity, and yield of products are strongly dependent on the metal target and plasma characteristics.
Journal of Power Sources, 2009
Hydrogen storage capacities of raw, oxidized, purified and Fe-doped multi-walled carbon nanotubes... more Hydrogen storage capacities of raw, oxidized, purified and Fe-doped multi-walled carbon nanotubes (MWCNTs) were studied by electrochemical method. Based on transmission electron microscopy and Raman spectroscopic data, thermal oxidation removed defective graphite shells at the outer walls of MWCNTs. The analysis results indicated that the acid treatment dissolved most of the catalysts and opened some tips of the MWCNTs. Thermal gravimetric analysis and differential scanning calorimetry results illustrated that by oxidation and purification of MWCNTs, the weight loss peak shifts toward a higher temperature. N 2 adsorption isotherms of the purified and oxidized MWCNTs showed an increase in N 2 adsorption below P/P o = 0.05, suggesting that microporous structures exist in the purified and oxidized MWCNTs. The electrochemical results revealed that the Fe-doped MWCNTs produced the highest hydrogen storage capacities compared to the other samples in various sweep rates. According to electrochemical analyses, the peak currents of hydrogen adsorption/desorption increased by increasing the catalyst's active surface.
Fuel and Energy Abstracts, 2011
Bromine Volumetric technique a b s t r a c t
The effect of Pd addition to Fe as catalysts on growth of carbon nanotubes by TCVD method
Applied Surface Science, 2008
The effects of Pd addition to Fe (Pd/Fe=0, 2.5/7.5, 5/5, 7.5/2.5 and 1) and growth temperatures (... more The effects of Pd addition to Fe (Pd/Fe=0, 2.5/7.5, 5/5, 7.5/2.5 and 1) and growth temperatures (920 and 970°C) on density, diameter and growth mode of carbon nanotubes (CNTs) have been studied. SEM observations and TG analyses confirmed that the CNT yields depend on Pd/Fe ratios as (7.5/2.5)>(5/5)>Pd>(2.5/7.5)>Fe at both growth temperatures. TEM data showed that addition of Pd results
Sensors and Actuators A-physical, 2010
We prepared porous silicon samples coated by continuous palladium layer in electroless process. S... more We prepared porous silicon samples coated by continuous palladium layer in electroless process. Scanning electron microscopy (SEM) showed cauliflower-shape Pd clusters on the surface. I-V curves of Schottky like Pd/porous Si samples were measured in air and in hydrogen. These measurements showed a metal-interface-semiconductor configuration rather than an ideal Schottky diode. Variations of the electrical current in the presence of diluted hydrogen at room temperature revealed that the samples can sense hydrogen in a wide range of concentration (100-40,000 ppm) without any saturation behavior. Hydrogen sensing properties of these samples were investigated at room temperature for a duration of nine months. Sample sensitivity (response time) decreased (increased) to a saturated value after 45 days. We discussed sensing and Schottky contact properties of the fresh and aged Pd/porous Si samples by variation of structure and chemical composition using SEM, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) data.
The Effect of Oxidation of Macroporous Silicon on Carbon Nanotubes Growth by TCVD Method
Synthesis and Reactivity in Inorganic Metal-organic and Nano-metal Chemistry, 2007
Carbon nanotubes (CNTs) were grown on deposited Ni on macroporous silicon by thermal chemical vap... more Carbon nanotubes (CNTs) were grown on deposited Ni on macroporous silicon by thermal chemical vapor deposition (TCVD) method using CH4 as the reaction gas. Macroporous silicon was fabricated by electrochemical etching of P‐type silicon in organic electrolytes. The effect of oxidation of porous silicon (PS) on growth rate, morphology and structure of CNTs has been studied. The SEM micrographs and
The effect of Pd addition to Fe as catalysts on growth of carbon nanotubes by TCVD method
Applied Surface Science, 2008
The effects of Pd addition to Fe (Pd/Fe = 0, 2.5/7.5, 5/5, 7.5/2.5 and 1) and growth temperatures... more The effects of Pd addition to Fe (Pd/Fe = 0, 2.5/7.5, 5/5, 7.5/2.5 and 1) and growth temperatures (920 and 970 °C) on density, diameter and growth mode of carbon nanotubes (CNTs) have been studied. SEM observations and TG analyses confirmed that the CNT yields depend on Pd/Fe ratios as (7.5/2.5) > (5/5) > Pd > (2.5/7.5) > Fe at both growth temperatures. TEM data showed that addition of Pd results in tip growth mode. From Raman spectroscopy data, the order of samples' structural quality ( IG/ ID ratio) are Fe > Pd/Fe (2.5/7.5) > (5/5) > (7.5/2.5) > Pd and the IG/ ID ratios increase by decreasing the growth temperature. Films with higher concentration of Fe (Pd/Fe = 0, 2.5/7.5) contain some single-walled carbon nanotubes.
Hydrogen Storage in Decorated Multiwalled Carbon Nanotubes by Ca, Co, Fe, Ni, and Pd Nanoparticles under Ambient Conditions
We report a study on hydrogen storage in Ca, Co, Fe, Ni, and Pd decorated multiwalled carbon nano... more We report a study on hydrogen storage in Ca, Co, Fe, Ni, and Pd decorated multiwalled carbon nanotubes (MWCNTs) by using two techniques: volumetric and electrochemical. The results showed that hydrogen molecules are adsorbed on the defect sites and transported to the ...
The Journal of Physical Chemistry C, 2014
Methane decomposition has been extensively investigated using a Q-switched Nd:YAG laser, focused ... more Methane decomposition has been extensively investigated using a
Q-switched Nd:YAG laser, focused on the metal catalysts including Ni, Fe, Pd, and Cu within the controlled chamber to verify the effect of catalyst, plasma properties, and yield and selectivity of the products. Fourier transform IR spectroscopy (FTIR) and gas chromatography (GC) are employed to support the characterization of the components. This indicates that methane is strongly decomposed within the metal-assisted laser-induced plasma, leading to the subsequent recombination and the production of heavier hydrocarbons. The dominant species, including propane, ethane, and ethylene, have been identified examining different metallic catalysts. The dissociation rate, conversion ratio, selectivity, and yield of products are strongly dependent on the metal target and plasma characteristics.
Journal of Power Sources, 2009
Hydrogen storage capacities of raw, oxidized, purified and Fe-doped multi-walled carbon nanotubes... more Hydrogen storage capacities of raw, oxidized, purified and Fe-doped multi-walled carbon nanotubes (MWCNTs) were studied by electrochemical method. Based on transmission electron microscopy and Raman spectroscopic data, thermal oxidation removed defective graphite shells at the outer walls of MWCNTs. The analysis results indicated that the acid treatment dissolved most of the catalysts and opened some tips of the MWCNTs. Thermal gravimetric analysis and differential scanning calorimetry results illustrated that by oxidation and purification of MWCNTs, the weight loss peak shifts toward a higher temperature. N 2 adsorption isotherms of the purified and oxidized MWCNTs showed an increase in N 2 adsorption below P/P o = 0.05, suggesting that microporous structures exist in the purified and oxidized MWCNTs. The electrochemical results revealed that the Fe-doped MWCNTs produced the highest hydrogen storage capacities compared to the other samples in various sweep rates. According to electrochemical analyses, the peak currents of hydrogen adsorption/desorption increased by increasing the catalyst's active surface.
Fuel and Energy Abstracts, 2011
Bromine Volumetric technique a b s t r a c t
The effect of Pd addition to Fe as catalysts on growth of carbon nanotubes by TCVD method
Applied Surface Science, 2008
The effects of Pd addition to Fe (Pd/Fe=0, 2.5/7.5, 5/5, 7.5/2.5 and 1) and growth temperatures (... more The effects of Pd addition to Fe (Pd/Fe=0, 2.5/7.5, 5/5, 7.5/2.5 and 1) and growth temperatures (920 and 970°C) on density, diameter and growth mode of carbon nanotubes (CNTs) have been studied. SEM observations and TG analyses confirmed that the CNT yields depend on Pd/Fe ratios as (7.5/2.5)>(5/5)>Pd>(2.5/7.5)>Fe at both growth temperatures. TEM data showed that addition of Pd results
Sensors and Actuators A-physical, 2010
We prepared porous silicon samples coated by continuous palladium layer in electroless process. S... more We prepared porous silicon samples coated by continuous palladium layer in electroless process. Scanning electron microscopy (SEM) showed cauliflower-shape Pd clusters on the surface. I-V curves of Schottky like Pd/porous Si samples were measured in air and in hydrogen. These measurements showed a metal-interface-semiconductor configuration rather than an ideal Schottky diode. Variations of the electrical current in the presence of diluted hydrogen at room temperature revealed that the samples can sense hydrogen in a wide range of concentration (100-40,000 ppm) without any saturation behavior. Hydrogen sensing properties of these samples were investigated at room temperature for a duration of nine months. Sample sensitivity (response time) decreased (increased) to a saturated value after 45 days. We discussed sensing and Schottky contact properties of the fresh and aged Pd/porous Si samples by variation of structure and chemical composition using SEM, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) data.
The Effect of Oxidation of Macroporous Silicon on Carbon Nanotubes Growth by TCVD Method
Synthesis and Reactivity in Inorganic Metal-organic and Nano-metal Chemistry, 2007
Carbon nanotubes (CNTs) were grown on deposited Ni on macroporous silicon by thermal chemical vap... more Carbon nanotubes (CNTs) were grown on deposited Ni on macroporous silicon by thermal chemical vapor deposition (TCVD) method using CH4 as the reaction gas. Macroporous silicon was fabricated by electrochemical etching of P‐type silicon in organic electrolytes. The effect of oxidation of porous silicon (PS) on growth rate, morphology and structure of CNTs has been studied. The SEM micrographs and
The effect of Pd addition to Fe as catalysts on growth of carbon nanotubes by TCVD method
Applied Surface Science, 2008
The effects of Pd addition to Fe (Pd/Fe = 0, 2.5/7.5, 5/5, 7.5/2.5 and 1) and growth temperatures... more The effects of Pd addition to Fe (Pd/Fe = 0, 2.5/7.5, 5/5, 7.5/2.5 and 1) and growth temperatures (920 and 970 °C) on density, diameter and growth mode of carbon nanotubes (CNTs) have been studied. SEM observations and TG analyses confirmed that the CNT yields depend on Pd/Fe ratios as (7.5/2.5) > (5/5) > Pd > (2.5/7.5) > Fe at both growth temperatures. TEM data showed that addition of Pd results in tip growth mode. From Raman spectroscopy data, the order of samples' structural quality ( IG/ ID ratio) are Fe > Pd/Fe (2.5/7.5) > (5/5) > (7.5/2.5) > Pd and the IG/ ID ratios increase by decreasing the growth temperature. Films with higher concentration of Fe (Pd/Fe = 0, 2.5/7.5) contain some single-walled carbon nanotubes.