ORCID Profile
0000-0002-0904-5593
Current Organisation
University of Wisconsin–Milwaukee
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Trans Tech Publications, Ltd.
Date: 10-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.1043.101
Abstract: Cobalt particles were deposited on treated CNTs via the Strong Electrostatic Adsorption (SEA) method. Cobalt loading on CNTs support was varied from 5 to 20 wt%. S les were characterized by N 2 adsorption and HRTEM. The results of TEM indicated that increasing the metal loading from 5% to 20% resulted in larger nanoparticles and also led to agglomeration.
Publisher: MDPI AG
Date: 22-12-2018
DOI: 10.3390/SYM11010007
Abstract: The strong electrostatic adsorption (SEA) method was applied to the synthesis of a cobalt (Co) catalyst on a multi-walled carbon nanotube (CNT) support. In order to uptake more of the cobalt cluster with higher dispersion, the CNT was functionalized via acid and thermal treatment. The Co/CNT catalyst s les were characterized by a range of methods including the Brunauer–Emmet–Teller (BET) surface area analyzer, transmission electron microscopy (TEM), X-ray powder diffraction (XRD) analysis, atomic absorption spectroscopy (AAS), and H2-temperature programmed reduction (H2-TPR) analysis. The data from the TEM images revealed that the catalyst was highly dispersed over the external and internal walls of the CNT and that it demonstrated a narrow particle size of 6–8 nm. In addition, the data from the H2-TPR studies showed a lower reduction temperature (420 °C) for the pre-treated catalyst s les. Furthermore, a Fischer–Tropsch synthesis (FTS) reaction was chosen to evaluate the Co/CNT catalyst performance by using a fixed-bed microreactor at different parameters. Finally finding the optimum value of the cobalt loading percentage, particle size, and calcination conditions of Co/CNT catalyst resulted in a CO conversion and C5+ selectivity of 58.7% and 83.2%, respectively.
Publisher: Trans Tech Publications, Ltd.
Date: 11-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.832.394
Abstract: The application of carbon nanotubes as a catalyst support has received considerable attention recently. The influence of acid and thermal treatments on the properties of multi-walled carbon nanotubes (MWCNTs) is presented in this paper. MWCNTs were treated with 65 wt% HNO 3 at the 120 °C for 14 h in order to open the caps and introduce functional groups on the MWCNTs. Then thermal treatment was carried out at 600, 700, 800, 900 °C for 3 h in flowing Ar gas in a tubular furnace. The MWCNTs were characterized by N 2 - adsorption, FESEM and Raman spectroscopy. The thermal treatment resulted in slight morphological changes of the MWCNTs. The acid and thermal treatments also increased the BET surface areas and pore volumes of the MWCNTs.
Publisher: Elsevier BV
Date: 04-2017
Publisher: MDPI AG
Date: 04-01-2019
DOI: 10.3390/SYM11010050
Abstract: Multiwalled carbon nanotubes (CNT) supported cobalt oxide was prepared as a catalyst by strong electrostatic adsorption (SEA) method. The CNT support was initially acid- and thermal-treated in order to functionalize the support to uptake more Co clusters. The Co/CNT were characterized by a range of analytical methods including transmission electron microscopy (TEM), temperature programmed reduction with hydrogen (H2-TPR), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, atomic absorption spectroscopy (AAS), Zeta sizer particle size analysis and Brunauer–Emmett–Teller (BET) surface area analysis. TEM images showed cobalt particles were highly dispersed and impregnated at both exterior and interior walls of the CNT support with a narrow particle size distribution of 6–8 nm. In addition, the performance of the synthesized Co/CNT catalyst was tested using Fischer–Tropsch synthesis (FTS) reaction which was carried out in a fixed-bed micro-reactor. H2-TPR profiles indicated the lower reduction temperature of 420 °C was required for the FTS reaction. The study revealed that cobalt is an effective metal for Co/CNT catalysts at pH 14 and at 900 °C calcination temperature. Furthermore, FTS reaction results showed that CO conversion and C5+ selectivity were recorded at 58.7% and 83.2% respectively, which were higher than those obtained using a Co/CNT catalyst which pre-treated at a lower thermal treatment temperature and pH.
Publisher: MDPI AG
Date: 14-07-2021
Abstract: The effect of reaction temperature, syngas space velocity, and catalyst stability on Fischer-Tropsch reaction was investigated using a fixed-bed microreactor. Cobalt and Manganese bimetallic catalysts on carbon nanotubes (CNT) support (Co-Mn/CNT) were synthesized via the strong electrostatic adsorption (SEA) method. For testing the performance of the catalyst, Co-Mn/CNT catalysts with four different manganese percentages (0, 5, 10, 15, and 20%) were synthesized. Synthesized catalysts were then analyzed by TEM, FESEM, atomic absorption spectrometry (AAS), and zeta potential sizer. In this study, the temperature was varied from 200 to 280 °C and syngas space velocity was varied from 0.5 to 4.5 L/g.h. Results showed an increasing reaction temperature from 200 °C to 280 °C with reaction pressure of 20 atm, the Space velocity of 2.5 L/h.g and H2/CO ratio of 2, lead to the rise of CO % conversion from 59.5% to 88.2% and an increase for C5+ selectivity from 83.2% to 85.8%. When compared to the other catalyst formulation, the catalyst s le with 95% cobalt and 5% manganese on CNT support (95Co5Mn/CNT) performed more stable for 48 h on stream.
Publisher: MDPI AG
Date: 11-2018
DOI: 10.3390/SYM10110572
Abstract: Pre-treating the multi-walled carbon nanotubes (CNTs) support by refluxing in 35 vol% nitric acid followed by heating at the temperature of 600 to 900 °C resulted in the formation of defects on the CNTs. Increasing the temperature of the pre-treatment of the CNTs from 600 °C to 900 °C, enhanced the fraction of cobalt-oxide nanoparticles encapsulated in the channels of CNTs from 31% to 70%. The performance of Co/CNTs in Fischer-Tropsch synthesis (FTS) was evaluated in a fixed-bed micro-reactor at a temperature of 240 °C and a pressure of 2.0 MPa. The highest CO conversion obtained over Co/CNTs.A.900 was 59% and it dropped by ~3% after 130 h of time-on-stream. However, maximum CO conversion using Co/CNTs.A.600 catalysts was 28% and it decreased rapidly by about 54% after 130 h of time-on-stream. These findings show that the combined acid and thermal pre-treatment of CNTs support at 900 °C has improved the stability and activity of the Co/CNTs catalyst in FTS.
Publisher: AIP Publishing LLC
Date: 2015
DOI: 10.1063/1.4919190
Publisher: Trans Tech Publications, Ltd.
Date: 09-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.625.328
Abstract: Strong Electrostatic Adsorption (SEA) is an effective method to synthesize and introduce Cobalt nanoparticles on Carbon Nanotubes (CNTs) support. Point of zero charge (PZC) of CNTs and optimum pH, the cobalt uptake versus different pH were investigated. By using the range of characterization methods such as TEM, FESEM and TPR catalyst prepared was studied. TEM and FESEM images indicate well-dispersed cobalt particles on the CNTs support. TPR was proven reduction peak at high temperature (530 o C) indicating strong interaction between Cobalt and CNTs support. SEA showed the desired method in preparing supported cobalt catalysts.
No related grants have been discovered for Omid Akbarzadeh Pivehzhani.