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catalyst-selectivity
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Analytical figures of merit for multisensor arrays
, Article ACS Sensors ; Volume 5, Issue 2 , 2020 , Pages 580-587 ; Kirsanov, D ; Sharif University of Technology
American Chemical Society
2020
Abstract
Multisensor arrays employing various sensing principles are a rapidly developing field of research as they allow simple and inexpensive quantification of various parameters in complex samples. Quantitative analysis with such systems is based on multivariate regression techniques, and deriving of traditional analytical figures of merit (e.g., sensitivity, selectivity, limit of detection, and limit of quantitation) for such systems is not obvious and straightforward. Nevertheless, it is absolutely needed for further development of the multisensor research field and for introducing these instruments into the general context of analytical chemistry. Here, we report on the protocol for...
From nitrate determination using microfluidic sensors to photocatalytic process intensification
, Article International Journal of Environmental Analytical Chemistry ; Volume 102, Issue 10 , 2022 , Pages 2416-2450 ; 03067319 (ISSN) ; Moraveji, M. K ; Mousavi, S ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
This review paper is devoted to the intensification of processes for nitrate removal. First, the developments of microfluidic sensors for nitrate detection and analysis have addressed. Second, the process variables of photocatalytic nitrate removal have been categorized according to their relationship with activity, selectivity and stability of the catalyst. The objective of this classification is to generate guidelines toward the photocatalytic process optimization. Third, because of the fact that a single method for nitrate removal faces some challenges, hybrid methods have been presented, and the best choice for nitrate removal can be referred to as photocatalytic – reverse osmosis...
Vanadium pentoxide catalyst over carbon-based nanomaterials for the oxidative dehydrogenation of propane
, Article Industrial and Engineering Chemistry Research ; Volume 52, Issue 46 , 2013 , Pages 16128-16141 ; 08885885 (ISSN) ; Kazemeini, M ; Khorasheh, F ; Rashidi, A. M ; Sharif University of Technology
2013
Abstract
A series of V2O5 catalysts supported on multiwall carbon nanotube (MWCNT), single wall carbon nanotube (SWCNT), and graphene were synthesized by hydrothermal and reflux methods for oxidative dehydrogenation of propane (ODHP) to propylene. The catalysts were characterized by techniques including the BET surface area measurements, XRD, FTIR, H2-TPR, NH3-TPD, FESEM, and UV-vis diffuse reflectance spectroscopy. The performance of the catalysts and the supports were subsequently examined in a fixed bed reactor. The main products were propylene, ethylene and CO x. The vanadium catalyst supported on graphene with C/V molar ratio of 1:1 synthesized through the hydrothermal method had the best...
Cobalt supported on CNTs-covered γ- and nano-structured alumina catalysts utilized for wax selective Fischer-Tropsch synthesis
, Article Journal of Natural Gas Chemistry ; Volume 21, Issue 6 , 2012 , Pages 713-721 ; 10039953 (ISSN) ; Kazemeini, M ; Khorasheh, F ; Zarkesh, J ; Rashidi, A ; Sharif University of Technology
2012
Abstract
Cobalt supported on carbon nanotubes (CNTs)-covered alumina has been recently developed and successfully utilized as a catalyst in Fischer-Tropsch synthesis (FTS). Problems associated with shaping of Co/CNTs into extrudates or pellets as well as catalyst attrition rendered these materials unfavorable for industrial applications. In this investigation regular γ- and nano-structured (N-S) alumina as well as CNTs-covered regular γ- and N-S-alumina supports were impregnated by cobalt nitrate solution to make new cobalt-based catalysts which were also promoted by Ru. The catalysts were characterized and tested in a micro reactor to evaluate their applicability in FTS. γ-Al2O3 was prepared by...
The influence of chromium substitution on an iron-titanium catalyst used in the selective catalytic reduction of NO
, Article Journal of Catalysis ; Volume 292 , August , 2012 , Pages 32-43 ; 00219517 (ISSN) ; Salehi, V ; Sharif University of Technology
Elsevier
2012
Abstract
A series of Cr-substituted Fe-Ti compounds were prepared by the co-precipitation method and were systematically investigated as catalysts for the selective catalytic reduction (SCR) of NO by NH 3. A variety of analytical techniques revealed that the Cr substitution amount affects the N 2 selectivity, SCR activity, redox behavior of NH 3/NO x, adsorption ability, and structure of catalysts in terms of surface properties, porosity, mobility of lattice oxygen, oxidative ability of Cr species, ratio of Bronsted acid sites and Lewis acid sites, NO x adsorption capacity, and structural disorder and distortion. In a series of Fe aCr 1-aTiO x (a = 1, 0.75, 0.5, 0.2, 0) catalysts, Fe 0.5Cr 0.5TiO x...
Modeling and sensitivity analysis of styrene monomer production process and investigation of catalyst behavior
, Article Computers and Chemical Engineering ; Volume 40 , 2012 , Pages 1-11 ; 00981354 (ISSN) ; Ebrahimi, A. N ; Ramazani S.A., A ; Abdollahzadeh, H ; Sharif University of Technology
2012
Abstract
In this work, a fundamental kinetic model based upon the Hougen-Watson non-porosity formalism was derived and used to simulate dehydrogenation and oxidation axial flow reactors. In addition, partial pressure profiles of components during styrene production process inside porous catalyst were obtained using Dusty-Gas model. The preservation equations are adopted to calculate temperature and flow profiles in the reactors filled with iron-potassium promoted catalyst pellets. The presented mathematical model for ethylbenzene dehydrogenation consists of nonlinear simultaneous differential equations with multiple dependent variables. Simulation results such as selectivity and operating temperature...
Comparison of two methods of iridium impregnation into HZSM-5 in the methanol to propylene reaction
, Article Catalysis Communications ; Volume 16, Issue 1 , 2011 , Pages 150-154 ; 15667367 (ISSN) ; Mohammadrezaei, A ; Asadi, M ; Golhosseini, R ; Naderifar, A ; Sharif University of Technology
2011
Abstract
In this paper, the effects of two methods of iridium impregnation into HZSM-5 on catalyst stability, selectivity for propylene and byproducts in the conversion of methanol to propylene (MTP) were investigated in a continuous flow isotherm fixed-bed reactor. XRD, BET surface area, NH 3-TPD and ICP-AES analytical techniques were applied to define the physical and chemical characteristics of zeolites. The reaction was conducted at 480°C and 1 bar with WHSV = 1 h -1, and with an equal weight percent of methanol and water in the feed. The results revealed that iridium impregnation into HZSM-5 powder led to enhanced propylene selectivity (8%) and catalyst stability while iridium impregnation into...
Synthesis of Reduced Graphene Oxide-Carbon Nanotubes (rGO-CNT) Composite and Its Use As a Novel Catalyst Support for Hydro-Purification of Crude Terephthalic Acid
, Article Industrial and Engineering Chemistry Research ; Volume 54, Issue 31 , 2015 , Pages 7591-7603 ; 08885885 (ISSN) ; Rashidi, A. M ; Safekordi, A. A ; Aghabozorg, H. R ; Khorasheh, F ; Sharif University of Technology
American Chemical Society
2015
Abstract
Palladium nanocatalysts supported on reduced graphene oxide (rGO), multi walled carbon nanotubes (MWCNT), and rGO/CNT composite were synthesized by a wet impregnation method using PdCl2 as a precursor. Palladium loading was 0.3 wt %, and the catalysts were reduced at 300°C. The catalysts were characterized by inductively coupled plasma, Brunauer-Emmett-Teller (BET) analysis, Fourier transform infrared spectroscopy, X-ray powder diffraction, transmission electron microscopy, temperatue-programmed reduction, temperatue-programmed desorption, and Raman spectroscopy. The performance of the catalysts was investigated for hydro-purification of crude terephthalic acid (CTA) containing...
Mo(vi) complex supported on Fe3 O4 nanoparticles: magnetically separable nanocatalysts for selective oxidation of sulfides to sulfoxides
,
Article
RSC Advances
;
Volume 5, Issue 66
,
Jun
,
2015
,
Pages 53349-53356
;
20462069 (ISSN)
; Balali, M
; Haghdoost, M. M
; Bagherzadeh, M
;
Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
A molybdenum complex, [MoO2 Cl2 (DMSO)2 ], was immobilized on amino propyl and Schiff base modified magnetic Fe3 O4 @SiO2 nanoparticles by covalent linkage. The resulting nanoparticles were used as efficient and recyclable catalysts for the selective oxidation of sulfides to sulfoxides using urea hydrogen peroxide as the oxidant. The complete characterization of catalysts was carried out by means of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), elemental analysis, FT-IR and Raman microprobe...
Effects of functionalization and catalyst treatments on selective behavior of multi-walled carbon nanotube-supported palladium catalysts in hydrogenation of acetylene
, Article Research on Chemical Intermediates ; Volume 41, Issue 2 , 2015 , Pages 1023-1034 ; 09226168 (ISSN) ; Kazemeini, M ; Rashidi, A. M ; Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
Two nanocatalysts of palladium over multi-walled carbon nanotubes (MWCNT) were synthesized and their catalytic properties evaluated in selective hydrogenation of acetylene. Different procedures were applied to synthesize catalysts which resulted in two distinct average particle sizes of palladium (Pd) over the MWCNT. The resulting catalysts displayed dissimilar NH3-TPD behaviors as well as different selectivity performances at lower temperatures. While enhancement of the hydrogen transfer mechanism occurred upon the temperature increase, similar behaviors for the aforementioned materials were obtained. Furthermore, it was revealed that the catalytic performance at higher temperatures did not...
Effect of recycle gas composition of the performance of Fischer-Tropsch catalyst
, Article Petroleum Science and Technology ; Volume 28, Issue 5 , 2010 , Pages 458-468 ; 10916466 (ISSN) ; Khorashe, F ; Safekordi, A. A ; Tavassoli, A ; Sharif University of Technology
Abstract
In this study, the influence of CO2 and CH4 on the performance and selectivity of Co-Ru/Al2O3 catalyst is investigated by injection of these gases (0-20 vol.% of feed) to the feed stream. The effect of temperature and feed flow rate are also inspected. The results show that low amounts of CO2 in the feed stream do not change the catalyst activity, but increasing the amount of CO2 (more than 10 vol.%), causes the CO conversion to decrease and the selectivity of heavy components to increase. Methane acts as an inert gas and does not affect the catalyst performance. Increasing feed flow rate has a negative effect on both CO conversion and heavy component selectivity. By raising the temperature,...
Catalytic behavior of an iron(III) complex containing an N,O-type bidentate oxazoline ligand for selective oxidation of sulfides
, Article Transition Metal Chemistry ; Volume 41, Issue 1 , 2016 , Pages 97-105 ; 03404285 (ISSN) ; Khaksar, M ; Arab, A ; Masoomi Jahandizi, R ; Bagherzadeh, M ; Boghaei, D. M ; Ellern, A ; Keith Woo, L ; Sharif University of Technology
Springer International Publishing
Abstract
The reaction of Fe(acac)3 and 2-(2′-hydroxyphenyl)oxazoline (Hphox) as a bidentate O,N donor ligand afforded a six-coordinated iron(III) complex [Fe(phox)2(acac)] with distorted octahedral configuration. The complex was isolated as an air-stable crystalline solid and characterized by elemental analysis, FTIR, solution electrical conductivity, and by single-crystal X-ray structure analysis. The structure, electronic properties, and vibrational normal modes of the complex were investigated by DFT. The use of this complex as a catalyst for the oxidation of sulfides to their corresponding sulfoxides using urea hydrogen peroxide as the primary oxidant was investigated. The catalyst shows very...
Aqueous phase reforming of glycerol using highly active and stable Pt0.05CexZr0.95-xO2 ternary solid solution catalysts
, Article Applied Catalysis A: General ; Volume 523 , 2016 , Pages 230-240 ; 0926860X (ISSN) ; Kazemeini, M ; Khorasheh, F ; Sharif University of Technology
Elsevier
Abstract
The aqueous phase reforming (APR) of glycerol is an attractive yet challenging pathway to convert abundant biomass into value added hydrogen. Pt catalysts have received attention due to their ability to produce hydrogen-rich gas under APR conditions. In this work, the conversion of glycerol into hydrogen is demonstrated using Pt0.05CexZr0.95-xO2 (x = 0, 0.29, 0.475, 0.66 and 0.95) solid solution catalysts. Both characteristic (XRD, BET, H2-TPR, CO-chemisorption, TEM and XPS) and reactivity measurements were used to investigate the activity of the catalysts. Results indicated that reactivity depended on the Ce/Zr ratio, which in turn affected the Pt oxidation state, active metal dispersion...
Hydrogenation of crude terephthalic acid by supported Pd and Pd-Sn catalysts on functionalized multiwall carbon nanotubes
, Article Chemical Engineering Research and Design ; Volume 109 , 2016 , Pages 41-52 ; 02638762 (ISSN) ; Safekordi, A. A ; Rashidzadeh, M ; Rashidi, A. M ; Khorasheh, F ; Sharif University of Technology
Institution of Chemical Engineers
2016
Abstract
Liquid phase hydro-purification of crude terephthalic acid (CTA) was performed using supported Pd and Pd-Sn catalysts on functionalized multi-wall carbon nanotubes (FMWCNT). Pd/FMWCNT catalysts were prepared by wet impregnation with Pd loadings of 0.05 to 0.6 wt.%. Pd-Sn/FMWCNT catalysts were prepared by co-impregnation (CI) and successive impregnation (SI) using 0.3 wt.% Pd loading and Sn/Pd molar ratios of 0.1 and 0.35 for the CI method and 0.05 to 0.35 for the SI method. Pd loading of 0.3 wt.% for Pd/FMWCNT was sufficient to decrease the 4-carboxybenzaldehyde (4-CBA) content of CTA from 2100 ppm to 5.5 ppm without excessive hydrogenation of terephthalic acid (TA). The commercial catalyst...
Gold nanoparticles anchored onto the magnetic poly(ionic-liquid) polymer as robust and recoverable catalyst for reduction of Nitroarenes
, Article Applied Organometallic Chemistry ; Volume 31, Issue 12 , 2017 ; 02682605 (ISSN) ; Ayati, S. E ; Firouzi, H. R ; Hosseini, S. H ; Pourjavadi, A ; Sharif University of Technology
Abstract
Gold nanoparticles supported on poly ionic-liquid magnetic nanoparticles (MNP@PIL@Au) were synthesized by reduction of HAuCl4 with sodium borohydride. The synthesized catalyst was characterized using by AAS, TEM, FT-IR, EDS, TGA and XRD techniques. The performance of the synthesized catalyst was investigated in the reduction of nitroarenes with NaBH4. The reaction was carried out for various nitroarenes in water and mild conditions with high yields. The catalyst selectivity for the reduction of nitro group in the presences of other functional groups such as halides and alkynes was fairly well. The recycling of the catalyst was done 8 times without any significant loss of its catalytic...
Efficient hardware implementation of real-time low-power movement intention detector system using fft and adaptive wavelet transform
, Article IEEE Transactions on Biomedical Circuits and Systems ; Volume 11, Issue 3 , 2017 , Pages 585-596 ; 19324545 (ISSN) ; Shabany, M ; Malekmohammadi, A ; Mohammadinejad, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
The brain-computer interfacing (BCI), a platform to extract features and classify different motor movement tasks from noisy and highly correlated electroencephalogram signals, is limited mostly by the complex and power-hungry algorithms. Among different techniques recently devised to tackle this issue, real-time onset detection, due to its negligible delay and minimal power overhead, is the most efficient one. Here, we propose a novel algorithm that outperforms the state-of-the-art design by sixfold in terms of speed, without sacrificing the accuracy for a real-time, hand movement intention detection based on the adaptive wavelet transform with only 1 s detection delay and maximum...
Novel synthesis of cobalt/poly vinyl alcohol/gamma alumina nanocomposite for catalytic application
, Article Applied Physics A: Materials Science and Processing ; Volume 123, Issue 5 , 2017 ; 09478396 (ISSN) ; Ahadian, M. M ; Rashidi, A ; Karimi, A ; Akhavan, O ; Sharif University of Technology
Springer Verlag
2017
Abstract
In this manuscript, synthesis of cobalt/poly vinyl alcohol (PVA)/gamma alumina nanocomposite via a simple room temperature, as well as its catalyst performance were explored. Brunauer–Emmett–Teller analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were conducted. The surface area of the polymeric composite was obtained to be 280 m2/g. The cobalt loading on the nanocomposite was measured using inductivity couple plasma. Transmission electron microscopy analysis showed that the size of cobalt crystalline encapsulate inside the polymer was confined to 5 nm. Magnetic property analysis, using vibrating sample magnetometer, confirmed...
Tungstate-loaded triazine-based magnetic poly(Bis-imidazolium ionic liquid): An effective bi-functional catalyst for tandem selective oxidation/Knoevenagel condensation in water
, Article Polymer (United Kingdom) ; Volume 112 , 2017 , Pages 342-350 ; 00323861 (ISSN) ; Tavakolizadeh, M ; Hosseini, S. H ; Pourjavadi, A ; Bennett, C ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
A novel bi-functional polymeric catalyst was synthesized by immobilization of tungstate anions onto the nitrogen rich poly(ionic liquid)/magnetic nanocomposite. The resulting catalyst has two types of catalytic sites: (i) immobilized WO4 anions with bis-imidazolium ionic liquid cation for selective oxidation of alcohols and (ii) basic amine groups for Knoevenagel condensation between produced aldehyde and malononitrile. Due to the polymeric nature of the catalyst, large amounts of tungstate and basic nitrogen groups were presented on the solid surface which led to a decrease in the applied catalyst mass for catalytic reaction. High catalytic activity and excellent selectivity of catalyst in...
Effect of recycle gas on activity and selectivity of Co-Ru/Al2O3 catalyst in fischer- Tropsch synthesis
, Article World Academy of Science, Engineering and Technology ; Volume 37 , 2009 , Pages 587-591 ; 2010376X (ISSN) ; Hatami, B ; Jokar, L ; Khorasheh, F ; Safekordi, A. A ; Sharif University of Technology
2009
Abstract
In industrial scale of Gas to Liquid (GTL) process in Fischer-Tropsch (FT) synthesis, a part of reactor outlet gases such as CO2 and CH4 as side reaction products, is usually recycled. In this study, the influence of CO2 and CH4 on the performance and selectivity of Co-Ru/Al2O3 catalyst is investigated by injection of these gases (0-20 vol. % of feed) to the feed stream. The effect of temperature and feed flow rate, are also inspected. The results show that low amounts of CO2 in the feed stream, doesn't change the catalyst activity significantly but increasing the amount of CO2 (more than 10 vol. %) cause the CO conversion to decrease and the selectivity of heavy components to increase....
Improved H2 production from the APR of polyols in a microreactor utilizing Pt supported on a CeO2–Al2O3 structured catalyst
, Article International Journal of Hydrogen Energy ; Volume 43, Issue 48 , 2018 , Pages 21777-21790 ; 03603199 (ISSN) ; Kazemeini, M ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this research, the activity and selectivity of a platinum-based catalyst for H2 production through aqueous phase reforming (APR) in a fixed-bed reactor (FBR) as well as, a structured catalyst microreactor (MR) were investigated. In this venue, first, an in-house designed MR was fabricated and the catalytic material was deposited on the channel walls of this steel made reactor. After verification of the stability of the coated layer, the prepared reactor was employed to investigate the APR reaction. In this regard, APR of the ethylene glycol and glycerol over Pt/Al2O3 and Pt/CeO2–Al2O3 catalyst were conducted in an MR and FBR. Obtained results demonstrated that employing Pt/CeO2–Al2O3 as a...