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Wrapping bacteria by graphene nanosheets for isolation from environment, reactivation by sonication, and inactivation by near-infrared irradiation
, Article Journal of Physical Chemistry B ; Volume 115, Issue 19 , 2011 , Pages 6279-6288 ; 15206106 (ISSN) ; Ghaderi, E ; Esfandiar, A ; Sharif University of Technology
American Chemical Society
2011
Abstract
Bioactivity of Escherichia coli bacteria (as a simple model for microorganisms) and interaction of them with the environment were controlled by their capturing within aggregated graphene nanosheets. The oxygen-containing functional groups of chemically exfoliated single-layer graphene oxide nanosheets were reduced by melatonin as a biocompatible antioxidant. While each one of the graphene (oxide) suspension and melatonin solution did not separately show any considerable inactivation effects on the bacteria, aggregation of the sheets in the melatonin-bacterial suspension resulted in trapping the bacteria within the aggregated sheets, i.e., a kind of inactivation. The bacteria trapped within...
Ion transport through graphene oxide fibers as promising candidate for bblue energy harvesting
, Article Carbon ; Volume 165 , 2020 , Pages 267-274 ; Esfandiar, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Nanostructured graphene based membranes demonstrated excellent capabilities in various applications in nanofiltration and energy conversion due to unique atomically smooth surfaces and adjustable pore size or interlayers spacing at Angstrom scales. There are some reports on the osmotic power generation using physical confinements and electrostatic interactions between ions and GO membranes. However, the results indicated insufficient power densities (˂1 W/m2) can be achieved because of swelling of interlayer spacing of the GO membranes upon exposure to aqueous solutions which results in reducing the influence of confinement on ionic motilities. Here, the GO fibers is presented as one...
Tuning of ionic transport through graphene oxide fibers by sheets size
, Article Iranian Journal of Physics Research ; Volume 21, Issue 1 , 2021 , Pages 41-49 ; 16826957 (ISSN) ; Esfandiar, A ; Khansanami, M ; Sharif University of Technology
Isfahan University of Technology
2021
Abstract
In this study, graphene oxide fibers are introduced as new graphene oxide (GO) membranes with the capability of ion selectivity. Graphene oxide fibers, like other macro structured membranes, are always associated with cavities and defects. To solve this problem, a 50% combination of graphene oxide suspension including small sheets with an average size of ~ 0.5 µm2 and large sheets with an area of more than 10 µm2 was used. According to the morphological results of scanning electron microscopy, as well as the amount of ionic transport through the fiber, reduction of cavities and its defects were confirmed. Moreover, it was found that ionic current through fibers consist of large and small GO...
Plasmonic enhancement of photocurrent generation in two-dimensional heterostructure of WSe2/MoS2
, Article Nanotechnology ; Volume 32, Issue 32 , 2021 ; 09574484 (ISSN) ; Esfandiar, A ; Sharif University of Technology
IOP Publishing Ltd
2021
Abstract
Enhancing the photoresponse of single-layered semiconductor materials is a challenge for high-performance photodetectors due to atomically thickness and limited quantum efficiency of these devices. Band engineering in heterostructure of transition metal chalcogenides (TMDs) can sort out part of this challenge. Here, we address this issue by utilizing the plasmonics phenomenon to enrich the optoelectronics property of the WSe2/MoS2 heterojunction and further enhancement of photoresponse. The introduced approach presents a contamination-free, tunable and efficient way to improve light interactions with heterojunction devices. The results showed a 3600-fold enhancement in photoresponsivity and...
High energy aqueous rechargeable nickel-zinc battery employing hierarchical niv-ldh nanosheet-built microspheres on reduced graphene oxide
, Article ACS Applied Energy Materials ; Volume 4, Issue 3 , 2021 , Pages 2377-2387 ; 25740962 (ISSN) ; Esfandiar, A ; Sharif University of Technology
American Chemical Society
2021
Abstract
Demand for high-capacity, long cycle life, and aqueous batteries based on abundant metals such as nickel, zinc, aluminum, and so on is rising in the energy storage field. In this study, we design a hierarchical morphology as a nanosheet-built microsphere of nickel vanadium layered double hydroxide (NiV LDH) with conductive agents graphene oxide (GO) and multiwalled carbon nanotubes (CNTs) through a low-cost hydrothermal synthesis method. The experimental results demonstrate that the graphitic structures and functional groups of the GO and CNT play an important role in controlling nucleation, growth speed, size, and finally morphology of hierarchical nanosheets. The electrochemical results...
Facile synthesis of highly efficient bifunctional electrocatalyst by vanadium oxysulfide spheres on cobalt-cobalt sulfonitride nanosheets for oxygen and hydrogen evolution reaction
, Article Electrochimica Acta ; Volume 391 , 2021 ; 00134686 (ISSN) ; Esfandiar, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Synthesis of efficient, low-cost, and stable bifunctional electrocatalysts with earth-abundant resources for electrochemical water electrolysis is a challenging subject for large-scale energy conversion processes. Herein, we report a high-performance electrocatalyst based on vanadium oxysulfide/cobalt-cobalt sulfonitride (VOS/Co-CoSN) for oxygen and hydrogen evolution reaction (OER and HER). The Co-CoSN film was synthesized on a copper sheet (CS) by a facile electrodeposition method. Then, VOS was electrochemically grown onto the Co-CoSN@CS electrode at various deposition times. At the optimal deposition time (300 s), the obtained VOS-300/Co-CoSN catalyst was studied for OER and HER in...
Mechanical behaviors of titanium nitride and carbide MXenes: A molecular dynamics study
, Article Applied Surface Science ; Volume 566 , 2021 ; 01694332 (ISSN) ; Esfandiar, A ; Rajabpour, A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
MXenes have recently witnessed significant evolution and advances in terms of their applications in different areas such as flexible electronics, energy storage devices, and coatings. Here, the mechanical properties of both pristine and functionalized Tin+1CnO2 and Tin+1NnO2 (n = 1, 2) are investigated utilizing classical molecular dynamics simulations. For eight different MXene structures, the stress-strain curves are calculated including Young's modulus, strength, and fracture strain. It is found that Ti2N holds the highest Young's modulus with the value of 517 GPa while Ti3C2 has the lowest one with the amount of 133 GPa. In addition, the strongest MXene structure is Ti2N while the...
Nonenzymatic sweat-based glucose sensing by flower-like au nanostructures/graphene oxide
, Article ACS Applied Nano Materials ; Volume 5, Issue 9 , 2022 , Pages 13361-13372 ; 25740970 (ISSN) ; Esfandiar, A ; Kazemi, M ; Sharif University of Technology
American Chemical Society
2022
Abstract
The development of a nonenzymatic glucose sensor working in real human body conditions through a noninvasive sampling approach has attracted considerable attention. Hence, this work focuses on the development of a new nonenzymatic glucose sensor based on flower-like Au nanostructures (F-AuNTs) and graphene oxide (GO) as a supporting matrix. The F-AuNTs-GO hybrid was synthesized by simple drop casting of the GO suspension onto the graphite sheet (GS) followed by electrodeposition of F-AuNTs on GO nanosheets at 3 V in a two-electrode system. The electrocatalytic activity of the F-AuNTs-GO/GS sensor toward glucose electrooxidation was initially evaluated in a 0.1 M buffer phosphate solution (pH...
Oppositely charged MXene fibers as a highly efficient osmotic power generator from sea and river water
, Article Journal of Materials Chemistry A ; Volume 10, Issue 46 , 2022 , Pages 24915-24926 ; 20507488 (ISSN) ; Esfandiar, A ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
Ion-exchange membrane-based reverse electrodialysis (RED) shows great potential for harvesting osmotic energy from seawater and converting it to electricity. However, their low energy conversion efficiency and huge ionic resistance hinder their application on large scales. The implementation of nanofluidic channels in RED devices can significantly improve the performance of osmotic power generators due to their selective and fast ion transport. However, technical challenges in scalable processing at the nanoscale and ion-selective membranes restrict their development in economically viable generators. Here, we report fibrous-based channels as positively and negatively charged MXene fibers...
Urchin-like hierarchical ruthenium cobalt oxide nanosheets on Ti3C2T: XMXene as a binder-free bifunctional electrode for overall water splitting and supercapacitors
, Article Nanoscale ; Volume 14, Issue 4 , 2022 , Pages 1347-1362 ; 20403364 (ISSN) ; Esfandiar, A ; Mehdipour, H ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
Synthesizing efficient electrode materials for water splitting and supercapacitors is essential for developing clean electrochemical energy conversion/storage devices. In the present work, we report the construction of a ruthenium cobalt oxide (RuCo2O4)/Ti3C2Tx MXene hybrid by electrophoretic deposition of Ti3C2Tx MXene on nickel foam (NF) followed by RuCo2O4 nanostructure growth through an electrodeposition process. Owing to the strong interactions between RuCo2O4 and Ti3C2Tx sheets, which are verified by density functional theory (DFT)-based simulations, RuCo2O4/Ti3C2Tx MXene@NF can serve as a bifunctional electrode for both water splitting and supercapacitor applications. This electrode...
Photodegradation of graphene oxide sheets by TiO2 nanoparticles after a photocatalytic reduction
, Article Journal of Physical Chemistry C ; Volume 114, Issue 30 , July , 2010 , Pages 12955-12959 ; 19327447 (ISSN) ; Abdolahad, M ; Esfandiar, A ; Mohatashamifar, M ; Sharif University of Technology
2010
Abstract
TiO2 nanoparticles were physically attached to chemically synthesized single-layer graphene oxide nanosheets deposited between Au electrodes in order to investigate the electrical, chemical, and structural properties of the TiO2/graphene oxide composition exposed to UV irradiation. X-ray photoelectron spectroscopy showed that after effective photocatalytic reduction of the graphene oxide sheets by the TiO2 nanoparticles in ethanol, the carbon content of the reduced graphene oxides gradually decreased by increasing the irradiation time, while no considerable variation was detected in the reduction level of the reduced sheets. Raman spectroscopy indicated that, at first, the photocatalytic...
Universal rotation of nanowires in static uniform electric fields in viscous dielectric liquids
, Article Applied Physics Letters ; Volume 113, Issue 6 , 2018 ; 00036951 (ISSN) ; Esfandiar, A ; Moshfegh, A. Z ; Sharif University of Technology
American Institute of Physics Inc
2018
Abstract
The wide utilization of nanomanipulation as a promising approach in microorganisms, nanoelectromechanical systems, and assembly of nanostructures remarks the importance of nanostructures' motion in electric fields. Here, we study the rotational dynamics of metallic and non-metallic nanowires (NWs) in a static uniform electric field in viscous dielectric liquids. For metallic NWs, it has been theoretically shown that the electric field-induced rotation is practically independent of the geometrical dimensions and the electrical properties of NWs. Our experimental results for suspended silver (Ag) NWs in microscope oil are perfectly in agreement with this model. However, in the case of TiO2...
Shooting at the nanoscale: Collection and acceleration of nanowires with an external electric field
, Article Applied Physics Letters ; Volume 114, Issue 1 , 2019 ; 00036951 (ISSN) ; Esfandiar, A ; Moshfegh, A. Z ; Sharif University of Technology
American Institute of Physics Inc
2019
Abstract
We report an approach for collecting, charging, and exceedingly fast motion of silver nanowires (Ag NWs) using an external static electric field. With a proper choice of suspension medium, dispersed Ag NWs can be efficiently driven to align and accumulate vertically on the edges of two parallel gold microelectrodes on a glass substrate surface by dielectrophoresis. Then, at sufficiently high electric fields (> 2.0 × 10 5 V/m), these NWs break at the electrode contact point while carrying some net charge. Afterwards, they immediately accelerate in the field direction and, despite an extremely low Reynolds number for the motion of NWs in viscous liquids, move with high speeds (> 25 mm/s)...
Bimetallic oxide nanosheets from nickel-vanadium layered double hydroxide as an efficient cathode for rechargeable nickel-zinc batteries
, Article Energy and Fuels ; Volume 35, Issue 22 , 2021 , Pages 18805-18814 ; 08870624 (ISSN) ; Esfandiar, A ; Iraji Zad, A ; Sharif University of Technology
American Chemical Society
2021
Abstract
Nickel-zinc batteries as safe and economic energy storage devices suffer from lack of high electrochemical performance of cathode materials. Herein, a new cathode material for rechargeable Ni/Zn batteries is introduced based on various compositions of mixed metal oxide (MMO) through a calcination process of nickel-vanadium layered double hydroxide at different temperatures. The results demonstrated that the prepared sample at 500 °C presents the best electrochemical properties such as a good electrochemical discharge capacity (278.4 mAh g-1 at 0.5 A g-1), good cycle life (capacity retention of 74% after 1000 cycles at 5 A g-1), and excellent rate capability (177 mAh g-1 at 5 A g-1). These...
Facile synthesis of cotton flower like Ni–Co/Ni–Co–O–P as bifunctional active material for alkaline overall water splitting and acetaminophen sensing
, Article International Journal of Hydrogen Energy ; Volume 47, Issue 76 , 2022 , Pages 32516-32530 ; 03603199 (ISSN) ; Esfandiar, A ; Iraji zad, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The development of electrode materials with simple preparation, favorable price, excellent electrocatalytic activity, and stability are some of the most important issues in the field of electrochemistry. Herein, we prepared Ni–Co/Ni–Co–O–P cotton flower like on a copper sheet (CS) by a convenient, efficient, and scalable electrodeposition method. The Ni–Co/Ni–Co–O–P was employed as effective binder free electrode material in two different applications such as electrocatalytic water splitting and acetaminophen (APAP) sensor. Remarkably, the Ni–Co/Ni–Co–O–P@CS exhibits low overpotentials of 310 and 90 mV at 10 mA cm−2 for oxygen and hydrogen evolution reactions in alkaline media, respectively....
Synergistic effect of reduced graphene oxide and carbon black as hybrid light absorber for efficient and antifouling texture-based solar steam generator
, Article Solar Energy ; Volume 238 , 2022 , Pages 226-237 ; 0038092X (ISSN) ; Iraji zad, A ; Esfandiar, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Efficient utilization of solar energy as the cleanest and most plentiful natural resource for drinking water is a water is as sustianble and environmental friendly approach to obviate long-standing water scarcity. Carbon-based photothermal absorbers due to broadband light absorption are very interesting in interfacial solar steam generation systems. Herein, we investigate the convenient application of reduced graphene oxide (rGO) nanosheets with carbon black (CB) nanoparticles on the cotton fabric as a flexible texture-based photothermal absorber. Polyurethane (PU) as a self-floating insulator foam was selected to manage the energy loss and preserve light converted to heat on the fabric...
Graphene/PbS as a novel counter electrode for quantum dot sensitized solar cells
, Article ACS Photonics ; Vol. 1, issue. 4 , March , 2014 , pp. 323-330 ; ISSN: 23304022 ; Samadpour, M ; Esfandiar, A ; Iraji Zad, A ; Sharif University of Technology
Abstract
PbS nanoparticles were in situ deposited on graphene sheets by a successive ionic liquid adsorption and reaction method to prepare a graphene/PbS composite counter electrode for CdS/CdSe quantum dot sensitized solar cells (QDSCs). Under 1 sun illumination, the cells with graphene/PbS counter electrodes (CEs) show a maximum energy conversion efficiency of 2.63%, which is remarkably higher than that of those employing PbS (1.28%) or graphene (0.23%) CEs. Electrochemical impedance spectroscopy analysis shows that graphene/PbS composite counter electrodes have lower charge-transfer resistance at the interface of the CE and the polysulfide redox electrolyte, compared to those cells with PbS and...
Selecting Support Layer for Electrodeposited Efficient Cobalt Oxide/Hydroxide Nanoflakes to Split Water
, Article ACS Sustainable Chemistry and Engineering ; Volume 4, Issue 6 , 2016 , Pages 3151-3159 ; 21680485 (ISSN) ; Esfandiar, A ; Qorbani, M ; Moshfegh, A. Z ; Sharif University of Technology
American Chemical Society
2016
Abstract
Energy and environment crises motivated scientists to develop sustainable, renewable, and clean energy resources mainly based on solar hydrogen. For this purpose, one main challenge is the low cost flexible substrates for designing earth abundant efficient cocatalysts to reduce required water oxidation overpotential. Here, a systematic morphological and electrochemical study has been reported for cobalt oxide/hydroxide nanoflakes simply electrodeposited on four different commercially available substrates, titanium, copper sheet, steel mesh, and nickel foam. Remarkable dependence between the used substrate, morphology, and electrocatalytic properties of nanoflakes introduced flexible porous...
Charge asymmetry effect in ion transport through angstrom-scale channels
, Article Journal of Physical Chemistry C ; Volume 123, Issue 2 , 2019 , Pages 1462-1469 ; 19327447 (ISSN) ; Fan, J ; Esfandiar, A ; Zhu, Y ; Wu, H ; Wang, F ; Sharif University of Technology
American Chemical Society
2019
Abstract
Structural and dynamic properties of ions confined in nanoslits are crucial to understand the fundamental mechanism underlying a wide range of chemical and biological phenomena. K + and Cl - show similar ion mobilities in a bulk aqueous solution, whereas they exhibit a remarkable difference when transporting through an angstrom-scale channel. Our molecular dynamics simulations uncover that such discrepancy originates from the subtle differences in their hydration structures and preferable locations across the channel. Opposite charge causes different water dipolar orientations around ions, mediating the distance and tribological interactions between hydrated ions and channel's walls....
Effect of film morphology on water oxidation enhancement in NiFeCo modified hematite photoanodes
, Article Surface and Coatings Technology ; Volume 421 , 2021 ; 02578972 (ISSN) ; Sobhkhiz Vayghan, N ; Esfandiar, A ; Dabirian, A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Hematite (α-Fe2O3) is a promising candidate for water oxidation applications due to its abundance in the earth crust and its suitable bandgap. However, hematite performance is severely limited by electron-hole recombination at its interface with the electrolyte; something that can be addressed using electrocatalysts. In this report, we evaluate the influence of a ternary NiFeCo co-catalyst to enhance the water oxidation performance of hematite photoanodes. Thus, NiFeCo co-catalyst is optimized for hematite thin films with i) dense and ii) porous (nano-rod) morphologies. Both hematite films are prepared using electron beam evaporation method followed by an annealing step and NiFeCo...