Supercritical water in top-down formation of tunable-sized graphene quantum dots applicable in effective photothermal treatments of tissues

Tayyebi, Ahmad,Akhavan, Omid,Lee, Byeong-Kyu,Outokesh, Mohammad Elsevier 2018 Carbon Vol.130 No.-

<P><B>Abstract</B></P> <P>Supercritical water was used for simultaneous fragmentation and reduction of graphene oxide (GO) sheets into water-dispersible graphene quantum dots (GQDs) with tunable sizes. Transmission electron microscopy (TEM) demonstrated that by increasing the temperature above the critical point of water, the average size and thickness of the GQDs were decreased and the size uniformity and production yield were increased. The results of thermal conductivity measurement of GQD nanofluids with different weight fractions indicated that the GQDs prepared at supercritical condition could enhance the thermal conductivity of water by 65% as compared to 35% for the GQDs synthesized at sub-critical conditions. Near-infrared (NIR) photothermal induction of a tissue-equivalent model (agarose gel) treated by the graphene nanomaterials showed that using the GQDs significantly increased the thermal conductivity (∼9.6 times), absorption coefficient (25%) and temperature uniformity (∼5.4-fold lower temperature difference) of the tissue in comparison with GO sheets. These results support the promising application of these GQDs in more efficient photothermal therapeutic purposes requiring lower thermal stresses.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Novel Visible Light Photocatalytic and Photoelectrochemical (PEC) Activity of Carbon-doped Zinc Oxide/Reduced Graphene Oxide: Supercritical Methanol Synthesis with Enhanced Photocorrosion Suppression

Tayyebi, Ahmad,Soltani, Tayyebeh,Lee, Byeong-Kyu,Outokesh, Mohammad,Tayebi, Meysam ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.723 No.-

<P><B>Abstract</B></P> <P>Carbon-doped zinc oxide/reduced graphene oxide (C-ZnO/rGO) was prepared by a facile one-pot supercritical methanol method. The synthesized C-ZnO/rGO nanocomposite with flower-like ZnO micro-rods (MRs) synergistically inherited all the advantages of carbon doping and rGO heterojunction and exhibited high photocatalytic activity for the photodegradation of methyl orange (MO) under visible light. The x-ray diffraction (XRD) results indicated that in presence of GO, a new carbon-doped phase was formed at the high temperature and pressure of supercritical methanol. The x-ray photoelectron spectroscopy (XPS) at low binding energies demonstrated that the valence band of C-ZnO-rGO is up-shifted by 0.35 ± 0.05 eV compared to that of ZnO MRs and narrowed the band-gap down to 2.9 eV. Under visible light irradiation, C-ZnO/rGO showed photocatalytic degradation of MO that was greatly increased by 4.5-fold compared to that of pure ZnO MRs. Measuring the photoelectrochemical (PEC) performance illustrated that C-ZnO/rGO showed higher photocurrent density in UV and visible region compared with those of ZnO MRs electrode. In addition, the incorporation of graphene sheets greatly suppressed the photocorrosion and photocurrent density decay of C-ZnO/rGO to only 0.5% and 10%, compared with 27% and 70% for neat ZnO MRs, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Carbon-doped ZnO/rGO was synthesized by facile one-pot supercritical methanol. </LI> <LI> The carbon-doped and oxygen vacancies enhanced the separation of electron-hole pairs. </LI> <LI> The introduction of graphene improved adsorption and anti-photocorrosion properties. </LI> <LI> Photocatalytic activity of C-ZnO/rGO increased by 4.5-fold compared to ZnO NRs. </LI> <LI> C-ZnO/rGO showed a high and stable photocurrent density in visible region. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Improved photocatalytic and photoelectrochemical performance of monoclinic bismuth vanadate by surface defect states (Bi_1-xVO₄)

Tayyebi, Ahmad,Soltani, Tayyebeh,Hong, Hyeonseon,Lee, Byeong-Kyu Elsevier 2018 JOURNAL OF COLLOID AND INTERFACE SCIENCE - Vol.514 No.-

<P><B>Abstract</B></P> <P>Due to visible light absorption and photochemical stability, Bismuth vanadate (BiVO<SUB>4</SUB>), recognized to be a promising photoanodes for designing high efficiency semiconductor photoelectrochemical (PEC) devices. To improve the photocatalytic and PEC performance of BiVO<SUB>4</SUB>, the porous monoclinic BiVO<SUB>4</SUB> with surface bismuth vacancy (Bi<SUB>1-x</SUB>VO<SUB>4</SUB> (s-m)) was obtained after the calcination of tetrahedron bismuth vanadate (BiVO<SUB>4</SUB> (s-t)). The photocatalytic experiments showed that despite the relatively lower adsorption capacity of Bi<SUB>1-x</SUB>VO<SUB>4</SUB> (s-m) as compared with BiVO<SUB>4</SUB> (s-t), its photocatalytic activity for the photodegradation of tetracyclines (TCs) was 15-fold greater. A four-layer thin films of BiVO<SUB>4</SUB> were deposited by spin coating with intermediate annealing treatment between layers and final calcination at 450 °C in air to shed light on carrier transport in Bi<SUB>1-x</SUB> VO<SUB>4</SUB> (s-m). The PEC results indicated that BiVO<SUB>4</SUB> (s-t) showed poor charge carrier mobility, while the Bi<SUB>1-x</SUB> VO<SUB>4</SUB> (s-m) showed great improvement by transformation of the tetrahedron BiVO<SUB>4</SUB> (s-t) into monoclinic phase, creation of new surface defect states and formation of a porous structure in Bi<SUB>1-x</SUB>VO<SUB>4</SUB> (s-m). Furthermore, Bi<SUB>1-x</SUB>VO<SUB>4</SUB> (s-m) showed enhanced and stable photocurrent density of 1.2 mA/cm<SUP>2</SUP> at 1.0 V vs. Ag/AgCl which was achieved under visible light illumination using 0.1 M Na<SUB>2</SUB>SO<SUB>4</SUB> aqueous solution. The porous Bi<SUB>1-x</SUB>VO<SUB>4</SUB> (s-m) showed the band gap narrowing of 0.08 eV, valence band up-shifting of 0.150 eV and 100 mV cathodic shift in onset potential relative to BiVO<SUB>4</SUB> (s-t). This enhancement is assigned to the longer electron lifetime of Bi<SUB>1-x</SUB>VO<SUB>4</SUB> (s-m), 10-fold compared to that of BiVO<SUB>4</SUB> (s-t), resulting in a minimized electron-hole pairs recombination.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Impact of Implementing Economic Integration between Iran and Korea on their Intra-Industry Trade(IIT)

Seyed Komail Tayyebi,Shirin Arbabian 한국경제연구학회 2006 Korea and the World Economy Vol.7 No.1

Enhanced photoelectrochemical (PEC) and photocatalytic properties of visible-light reduced graphene-oxide/bismuth vanadate

Soltani, Teyyebah,Tayyebi, Ahmad,Lee, Byeong-Kyu Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.448 No.-

<P><B>Abstract</B></P> <P>A simple visible-light-assisted photocatalytic reduction of graphene oxide (GO) to reduced graphene oxide (rGO) using BiVO<SUB>4</SUB> (BVO) in BVO/GO was designed to remarkably improve the photocatalytic degradation and photoelectrochemical (PEC) water splitting efficiencies of BVO. The resulting smaller particle size and strong interfacial interaction on the graphene sheet of the prepared BVO/rGO nanocomposite (NC) enhanced the photocatalytic degradation of tetracycline (TC) and methylene blue (MB) from aqueous solution, and also PEC water splitting. The photocatalytic degradation of MB and TC from aqueous solution using BVO/rGO was enhanced almost 2-fold compared to using BVO with complete photodegradation being achieved in 60 and 55 min of visible-light irradiation, respectively. The photocurrent onset potential of BVO/rGO was negatively shifted by −0.2 V vs. Ag/AgCl. The photocurrent density of BVO/rGO was greatly improved to 133 µA cm<SUP>−2</SUP> at 0.8 V vs. Ag/AgCl, as compared to 21 µA cm<SUP>−2</SUP> with BVO. The charge recombination time was greatly increased from 5 s<SUP>−1</SUP> for BVO to 11 s<SUP>−1</SUP> for BVO/rGO. The BVO/rGO photoanode exhibited long-term operation stability by maintaining 90.2% of the initial photocurrent density after 2400 s, while BVO showed poor stability of 65.1%. The great improvement of photocatalytic (2.0-fold) and PEC water splitting activity (6.3-fold) in BVO/rGO was attributed to the longer electron lifetime (2.2-fold), enhanced carrier concentration (5.87-fold), reduced interfacial electron transfer resistance, excellent stability and reusability, reduced particle size, and extended photoresponse range, which were derived from the ultimate coverage of BVO by rGO.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Photocatalytic reduction of GO produced complete coverage of BVO by rGO sheets. </LI> <LI> Photodegradation of MB and TC was 2-fold greater than that using BVO. </LI> <LI> Photocurrent density of BVO/rGO (133 µA cm<SUP>−2</SUP>) was greatly increased compared to that of BVO (21 µA cm<SUP>−2</SUP>). </LI> <LI> BVO/rGO photoelectrode exhibited a very high stability of 90% even after 2400 s. </LI> <LI> Charge recombination time of BVO/rGO (11 s<SUP>−1</SUP>) was greatly increased compared to that of BVO (5 s<SUP>−1</SUP>). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Quick and enhanced degradation of bisphenol A by activation of potassium peroxymonosulfate to SO₄ ⁻ with Mn-doped BiFeO₃ nanoparticles as a heterogeneous Fenton-like catalyst

Soltani, Tayyebeh,Tayyebi, Ahmad,Lee, Byeong-Kyu Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.441 No.-

<P><B>Abstract</B></P> <P>Mn-doped BiFeO<SUB>3</SUB> magnetic nanoparticles (BFO MNPs), namely BiFe<SUB>1−x</SUB>Mn<SUB>x</SUB>O<SUB>3</SUB> (x = 0.05 and 0.10), were successfully synthesized using a simple and novel sol–gel method and then applied as a highly efficient peroxymonosulfate (KHSO<SUB>5,</SUB> PMS) activation catalyst for the fast degradation of bisphenol A (BPA) from aqueous solution. The strong PMS activation ability of 10% Mn-doped BFO MNPs without any metal leaching due to the simultaneous effects of iron and manganese ions in the production of radical sulfate (SO<SUB>4</SUB> <SUP> −</SUP>), caused complete BPA degradation in 15 min, which was much faster than that using combinations with H<SUB>2</SUB>O<SUB>2</SUB>. TOC was reduced to 33%, 23% and 13% by PMS activated with BFO, 5 and 10% Mn doped BFO, respectively, which are 2.1, 2.6 and 3.15-fold lower than that same nanoparticles activated with H<SUB>2</SUB>O<SUB>2</SUB>. The photocatalytic mechanism of BPA with the simultaneous effects of iron and manganese ions in Mn-doped BFO was explored. The addition of KBrO<SUB>3</SUB> and NaNO<SUB>3</SUB> salts into Mn-doped BFO/PMS system reduced the complete BPA degradation time to 10 min, whereas Na<SUB>2</SUB>CO<SUB>3</SUB> and NaCl salt addition retarded it, because salt addition can generate radical species that are either more or less active than SO<SUB>4</SUB> <SUP> −</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mn-doped BFO catalyst greatly improved the heterogeneous activation of PMS (HSO<SUB>5</SUB> <SUP>−</SUP>). </LI> <LI> HO<SUP> </SUP> or SO<SUB>4</SUB> <SUP> −</SUP> are the main species in the photo-Fenton catalytic oxidation of BPA. </LI> <LI> The coupling of HSO<SUB>5</SUB> <SUP>−</SUP> with Fe<SUP>2+</SUP> and Mn<SUP>2+</SUP> led to the effective formation of SO<SUB>4</SUB> <SUP> −.</SUP> </LI> <LI> Mn (10%)-doped BFO MNPs completely degraded BPA in 15 min with SO<SUB>4</SUB> <SUP> −.</SUP> </LI> <LI> KBrO<SUB>3</SUB> and NaNO<SUB>3</SUB> salts further increased BPA degradation as compared to PMS. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Efficient promotion of charge separation with reduced graphene oxide (rGO) in BiVO₄/rGO photoanode for greatly enhanced photoelectrochemical water splitting

Soltani, Teyyebah,Tayyebi, Ahmad,Lee, Byeong-Kyu Elsevier 2018 Solar Energy Materials and Solar Cells Vol. No.

<P><B>Abstract</B></P> <P>Although BiVO<SUB>4</SUB> (BVO) continues to attract strong attention as an ideal reactive semiconductor, its photoelectrochemical (PEC) water splitting performance remains low because most of the charge carriers are easily recombined in the bulk or on the surface of the photoanode before reaching the fluorine-doped tin dioxide (FTO). This study presents a facile and simple, visible-light-assisted, photocatalytic reduction of graphene oxide (GO) by using BVO for the preparation of highly stable BVO/reduced GO (rGO) nanocomposites with two different rGO weight ratios (5% and 10%). These as-prepared BVO/rGO nanocomposites were then drop-cast on an FTO substrate to demonstrate the key role played by the rGO in greatly improving the electron transport in the BVO/rGO films. In PEC water splitting experiments, the BVO/rGO-10% photoelectrode showed the highest photocurrent density (554.4 µA cm<SUP>−2</SUP> at 1.2 V vs. Ag/AgCl), compared to BVO (111.7 µA cm<SUP>−2</SUP>) and BVO/rGO-5% (377.9 µA cm<SUP>−2</SUP>). The stable BVO/rGO also showed the highest charge carrier density, with an extended lifetime and improved the electrical conductivity, as compared to BVO. These results contributed to the excellent PEC performance of the BVO/rGO photoanode. Under simulated solar light illumination, the open-circuit potential (OCP) of the BVO/rGO films was shifted to a more negative value due to the enhanced electron-hole separation in the films. The photocurrent yields of the BVO and BVO/rGO electrodes were dependent on the solution pH. The photocurrent densities were higher over the full range of measured potential (0 to + 1.2 V vs. Ag/AgCl) in the NaOH electrolyte (1 M, pH = 13.5) than in the Na<SUB>2</SUB>SO<SUB>4</SUB> electrolyte (0.1 M, pH = 6.5). This work demonstrates the essential role of the rGO coverage in the great enhancement of electron transport through the rGO in the BVO/rGO film.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Facile, visible-light-assisted, photocatalytic reduction of GO by BVO was developed. </LI> <LI> BVO/rGO greatly increased the photocurrent density up to 554.44 µA cm<SUP>−2</SUP>. </LI> <LI> BVO/rGO showed much better stability, photocurrent and IPCE than BVO did. </LI> <LI> BVO/rGO increased the charge carrier lifetime/concentration and electron conductivity. </LI> </UL> </P>

Improved photoelectrochemical performance of molybdenum (Mo)-doped monoclinic bismuth vanadate with increasing donor concentration

Tayebi, Meysam,Tayyebi, Ahmad,Lee, Byeong-Kyu Elsevier Science Publishers 2019 Catalysis today Vol.328 No.-

<P><B>Abstract</B></P> <P>Molybdenum (Mo)-doped Monoclinic Bismuth Vanadate (Mo-BiVO<SUB>4</SUB>; BVO) catalysts were fabricated via a simple dip coating method. We systematically studied the effect of Mo-doping with various concentration (1–5%) in BVO electrode through photoelectrochemical (PEC), Mott-Schottky and impedance measurement. Intermediate heat treatment and number of successive dip coating deposition were utilized to control the monoclinic crystallization and thickness of Mo-BVO photoanodes. Furthermore, the effect of Mo-doping in morphology, structure, chemical states and optical properties of the obtained electrodes were characterized by different physico-chemical and morphological methods BVO with 2% Mo doping (2% Mo-BVO) showed the best PEC performance, of about 15 times higher than that of the pure BVO. Improved charge carrier transport and optimized light absorption obtained upon Mo doping into the BVO crystal lattice while the monoclinic scheelite structure with small band-gap was retained. To understand the effect of Mo-doping, Mott Schottky and Impedance measurement carried out, in order to evaluate the donor concentration and conductivity of pure BVO and Mo-BVO. Interestingly, 2% Mo-BVO showed the maximum donor concentration (5.7E + 27) and minimum flat band potential (V<SUB>fb</SUB> = −0.45) compared to other prepared electrodes. Furthermore, we attempt to discuss the improved PEC performance of Mo-BVO using high donor concentration, up-shifting of Fermi level and consequently facilitating electrons transport in Mo-BVO compared to pure BVO.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mo-BVO electrodes were fabricated via a four dip-coating cycles method. </LI> <LI> Photocurrent density increased 15-fold for 2% Mo-BVO compared with pure BVO. </LI> <LI> Mott-Schottky results indicated 2% Mo-BVO has the maximum donor concentration. </LI> <LI> The PEC measurement showed shifting of onset potential to lower voltage for Mo-BVO. </LI> <LI> The Impedance data exhibited 2% Mo-BVO has the best PEC performance compared to other photoanodes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microstructure, Texture and Tensile Properties of Nickel/Titanium Laminated Composites Produced by Cross Accumulative Roll Bonding Process

Shoufa Liu,Moslem Tayyebi,Amir Hossein Assari,Adelajda Polkowska,Sebastian Lech,Wojciech Polkowski 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.12

The purpose of this paper is to examine the microstructural evolution and mechanical properties of Ni/Ti laminatedcomposite produced by a cross-accumulative roll bonding (CARB) method. The SEM images showed that no void anddelamination were observed which indicates that the layers were strongly bonded together. In addition to the thicknessreduction and increased number of interfaces, plastic instabilities took place with an increase in CARB passes; the wavylikeinterfaces appeared as a result of the necking and shear bands formation. However, due to the effect of uniform rollingpressure and rotation of rolling direction during the CARB process, all layers remained continuous in all CARB passes. The most marked observation coming from EBSD analyses was the formation of fine grains surrounded by a high fractionof high-angle grain boundaries (HAGBs). Based on the microtexture analyses on Ti and Ni layers, it was found that byincreasing the rolling passes, a crystallographic texture formed in Ti layers gradually changes from the basic {0001}<112̅0 > system into the system dominated by {0001}<101 ̅0 > prismatic-like orientations. In the case of the crystallographictexture formed in Ni layers, there was a significant increase in the intensity of the Q{013}<231>; P{011}<122 > andGoss {011}<100>, indicating the formation of shear strain-assisted type of texture. Furthermore, with an increase in theCARB passes, the mechanical properties improved due to strong interfaces and grain refinement. The maximum values ofthe yield strength, tensile strength, and elongation reached 842 MPa, 936 MPa, and 7.1% respectively, in the final CARBpass. In addition, ductile fracture mainly occurred on fracture surfaces of Ti and Ni layers even though by increasingpasses, cleavage facets appeared due to strain hardening.

Extensive Acute Lower Extremity Arterial Thrombosis: A Major Thrombus Formation Caused by COVID-19

Pouya Tayebi,Mahmoud Sadeghi Haddad Zavareh,Gooya Tayyebi,Fatemeh Zahra Abdollahi,Fatemeh Mahmoudlou 대한혈관외과학회 2021 Vascular Specialist International Vol.37 No.4

Acute thromboembolic events have been frequently reported in patients with coronavirus disease 2019 (COVID-19) due to an increase in the coagulation system activity and endothelial dysfunction. This report describes a patient with COVID-19 who initially reported respiratory symptoms and developed acute lower limb ischemia secondary to extensive macrovascular arterial thrombosis, which was treated with thrombectomy. The development of such extensive arterial thrombosis with anticoagulants at therapeutic doses is a new sign of increased viral pathogenicity, and it is necessary to develop and apply updated prophylaxis protocols for thrombosis in these patients.