Journal of Alloys and Compounds (09258388)984
Herein, as a novel idea, a microwave (MW) post-treatment strategy is proposed to modify the structure and surface characteristics of already prepared activated carbons (ACs) for application in non-aqueous Electric Double-Layer Capacitors. Pistachio nutshell-derived carbon is first KOH-activated and then subjected to MW irradiation for 0, 2, 5, and 10 minutes. X-ray Diffraction and Raman analyses show that MW post-treatment leads to structural modifications, and FTIR and XPS analyses reveal relative elimination of surface functional groups which results in subsequent enhancement in water contact angle and renders more favorable surface wetting of carbon by non-aqueous organic electrolyte. The performance characteristics of symmetrical non-aqueous supercapacitors incorporated with the prepared ACs show a significant positive effect of MW irradiation in such a way that 0 and 10-minute-irradiated ACs demonstrate 152 and 392 F g−1 capacities, respectively, at 1.75 A g−1, with the corresponding specific energies and powers of 340 Wh kg−1 and 11 kW kg−1 for AC-10, respectively. This remarkable enhancement in the electrochemical performance is attributed to the effective role of the MW post-treatment in modifying the AC structure as well as providing AC surfaces that have better wettability with less polar non-aqueous electrolyte. Moreover, this strategy is additionally applicable to make hydrophobic activated carbons for other applications as the absorption of less polar contaminants from liquid or gaseous environments. © 2024 Elsevier B.V.
Torabi, M.,
Karimi shervedani, R.,
Shahrokhi, S.M.,
Khosravi, M.,
Mohagheghnia, M.,
Hakami shalamzari, Y. Journal of Energy Storage (2352152X)102
This research introduces the supercapacitive behavior of porous coral-like nickel-cobalt-phosphide composited with reduced graphene nanosheets (RGNs) using a straightforward one-step hydrothermal process. Several surface and electrochemical methods were used to follow the fabrication and study the electrochemical behavior and supercapacitive charge storage performance of the composite (NiCoP/RGNs) and its ancestors (NiP, CoP, NiP/RGNs, and CoP/RGNs). The effects of each component, NiP, Co, and graphene, on the performance of the composite were studied. In the composite with the optimum proportion of ingredients, the presence of NiP contributed to the high specific capacity, Co enhanced the intrinsic conductivity and electrochemical activity, and graphene significantly increased the surface area and electrical conductivity, leading to improved overall performance of the NiCoP/RGNs composite. The NiCoP/RGNs composite exhibited a uniformly shaped porous nanostructure with coral-like morphology and superior specific capacity of 982 C g−1 at 1 A g−1 (2455.6 F g−1), which can be attributed to its substantial specific surface area, notable intrinsic conductivity, and fleeting reversible faradic reaction properties. The asymmetric supercapacitor (ASC), made up of stainless steel modified with NiCoP/RGNs as a positive electrode and industrial active carbon as a negative electrode, revealed a high energy density of 54.63 W h kg−1 at a power density of 749.49 W kg−1 with 81 % capacity retention after 4000 cycles. The research may open up possibilities for the one-step, straightforward production of highly porous bimetallic phosphide materials, combined with graphene nanosheets, to store electrochemical energy. © 2024 Elsevier Ltd
Desalination (00119164)577
The photosynthetic chemical desalination cell (PCDC) represents a cost-effective and ecologically friendly alternative for desalinization. Nevertheless, these cells exhibit a limited desalination rate, creating challenges in terms of commercialization due to the growing internal resistance and its impact on desalination. To tackle this issue, the study explores the use of series and parallel arrangement of three CPDCs to enhance the salinity removal percentage (SR%) and flow rate, while concurrently reducing internal resistance. Findings revealed that the series configuration of cells attained a superior SR% when compared to a lone CPDC. Conversely, the parallel configuration of cells led to an increased flow rate of the desalinized stream. Equivalent cells, featuring distinct currents, were fabricated for both configurations. The research also placed emphasis on evaluating the impact of variations in internal resistance and their significance in each configuration, a crucial aspect for facilitating the scaling up of the process. From an energy consumption standpoint, the parallel configuration was identified as being more efficient. The series configuration, with a flow rate of 0.9 mL/min, exhibited the highest desalination rate (DR), whereas the parallel equivalent cell, possessing the same flow rate, demonstrated the lowest DR. Synopsis: The development of CPDC technology has the potential to result in sustainable carbon dioxide capture, the production of valuable biomass, hybrid desalination, and power generation without the presence of any reject brine. © 2024 Elsevier B.V.
Ghorbani, M.,
Solaimany nazar a.r., A.R.,
Frahadian, M.,
Khosravi, M. Journal of Photochemistry and Photobiology A: Chemistry (18732666)429
A series of Z-scheme 3D ZnO@BiOBr photocatalysts were prepared by the hydrothermal method. The morphology of BiOBr facing the surface of the ZnO nanorods was controlled under regulating the proper experimental conditions. The photocatalysts were characterized by XRD, FT-IR, FE-SEM, TEM, BET-BJH, UV–vis DRS and PL analyses. The ZnO@BiOBr composites showed the highest photodegradation ability of metronidazole (MTZ), which was about 9.75 and 3.54 times higher than those of the pure ZnO and BiOBr, respectively. In addition, the Z-scheme ZnO@BiOBr photocatalysts indicated high stability after four cycles of MTZ photoreduction. The optimal values of the operating parameters were determined by the Box-Behnken design (BBD) with irradiation time = 112 min, pH = 6, initial MTZ concentration = 20 ppm, and catalyst dose 0.5 g/l. The maximum total organic carbon (TOC) degradation efficiencies in the presence of 3D ZnO@BiOBr reached 76.7% at the optimum conditions. The maximum MTZ removal efficiency was 87.72%. The photodegradation of MTZ by a binary composite followed the first-order kinetics. In addition, the effects of adding inorganic ions at different concentrations on the degradation of MTZ were investigated. Based on the trapping experiments, OH• and O2–• improved the photodegradation process. © 2022
Nasiri, M.,
Solaimany nazar a.r., A.R.,
Frahadian, M.,
Khosravi, M. Environmental Nanotechnology, Monitoring and Management (22151532)18
The photoelectrochemical degradation of methylene blue (MB) dye through the stabilization of BiOBr/Bi2S3/TiO2/GO nanocatalyst was examined. The nanocatalysts were synthesized using the solvothermal method and the spin coating method was applied for the coating. In photoelectrochemical processes, the coated-FTO was used as the anode and the graphite as the cathode. An initial dye concentration of 10 mg/L, the initial pH level of 6, photocatalyst dosage of 0.5 g/L, and irradiation time of 90 min, were the optimal conditions for the photocatalytic degradation. The experimental value of degradation in MB was conceived to be 97.9%. The optimal conditions for the photoelectrochemical degradation of MB include the initial concentration of the dye of 17 mg/L, the initial pH level of 6, the number of coatings of 3 times, and the irradiation time of 90 min, and the experimental value of 98.7% was obtained. The current density produced under optimal conditions was calculated and the effect of the light source and nitrogen gas on the efficiency was observed. The possibility of recycling the photocatalyst up to 4 times in both suspended and stabilized forms, confirms the stability, repeatability, and optimal activity of the photocatalyst. The economic performance was also investigated. According to the trapping tests, holes and hydroxyl radicals were the main active species in the degradation process. © 2022 Elsevier B.V.
Advanced Powder Technology (15685527)33(5)
The integration of Bi2MoO6 with MIL-101(Fe) as a novel structure enhanced photocatalytic activity for RhB degradation. Bi2MoO6/MIL-101(Fe) composites were synthesized via the solvothermal procedure and characterized by XRD, EDX, FE-SEM, TEM, FT-IR, BET, TGA, UV–vis DRS, and PL. The optimal molar ratio Bi2MoO6:MIL-101(Fe) equal to 1:1 showed better photocatalytic activity than Bi2MoO6 and MIL-101(Fe) and other heterostructure composites. The effect of pH (5–9), reaction time (60–120 min), catalyst concentration (0.1–0.5 g/L), and dye concentration (10–20 ppm) were investigated on the removal performance of RhB by using central composite face-centered (CCF). In the optimal process factors where the [Catalyst]:0.4 g/L, [RhB]:20 ppm, pH: 6.5, irradiation time: 120 min, the RhB and TOC removal efficiency were 85% and 84.2%, respectively. The holes and superoxide radicals played a major role in the degradation of RhB. The addition of salt (NaCl, Na2SO4, and NaHCO3) at different concentrations (100, 200, 400, and 800 ppm) revealed that the salts have an inhibitory role in the photocatalytic performance. At low concentrations of 100 ppm, the salts had a negative effect on removal efficiency (kPure water = 0.0155 min−1, kNaCl = 0.0075 min−1, kNa2SO4 = 0.0132 min−1, kNaHCO3 = 0.006 min−1). Increasing the salt concentration to 800 ppm caused improved efficiency for NaCl (kNaCl = 0.0141 min−1), while for Na2SO4 this trend was decreasing (kNa2SO4 = 0.011 min−1), and for NaHCO3 sharply diminished (kNaHCO3 = 0.0026 min−1). © 2022 The Society of Powder Technology Japan
Advanced Materials Technologies (2365709X)6(10)
It is predicted that the future of energy will mainly rely on batteries such as vanadium redox flow batteries (VRFBs), and its related research has already attracted significant attention. The primary function of a membrane in VRFBs is to control proton transport between the half-cells and to hinder admixing the anolyte and catholyte at the same time. However, to develop a low-cost and energy-efficient VRFB, other membrane roles are crucial. The combination of a highly stable backbone of polytetrafluoroethylene with hydrophilic perfluorinated-vinyl-polyether side chains equipped with sulfonic acid groups (Nafion membranes) has led to a breakthrough in the field. However, suffering from high cost and low selectivity, these perflurinated membranes are not properly qualified for VRFBs. Sulfonation of aromatic hydrocarbon polymers is suggested as cost-effective alternative chemistry for VRFBs’ membrane design. Further tunning the performance of the membrane and VRFB is obtained through designing their microstructure by different tools, especially adjusting the degree of sulfonation and degree of branching, utilizing additional membrane layers, and incorporation of particles in the polymer matrix. In this review, the studies performed to develop membranes for VRFBs are discussed as a road map for the development of advanced membranes qualified for VRFBs. © 2021 Wiley-VCH GmbH
Science of the Total Environment (00489697)779
In this study, a chemical photosynthesis desalination cell (CPDC) was investigated for saltwater desalination. The cell consisted of three main parts: (1) an anodic compartment where the oxidation reaction occurs, releasing electrons, (2) a cathode compartment where the required soluble oxygen is provided by microalgae photosynthesis, and (3) an electrodialysis desalination cell installed between the cathode and anode. In the anode, a novel idea was adopted to shorten the desalination duration and increase the salinity rate using a chemical oxidation reaction in combination with the biocathode. The CPDC contributed to the carbon dioxide biological sequestration (reducing air pollution), produced microalgae biomass as a source of renewable energy and generated electricity. In the investigated CPDC, microalgae were used to supply the required oxygen solution as an electron acceptor. The metal anode-microalgae biocathode battery could provide the required energy for electrodialysis. In addition, some extra electricity was generated with a maximum excess power density of 32.4 W/m3 per volume of the net anodic compartment, 16.2 W/m3 per volume of the net cathodic compartment, and 3.07 W/m2 of membrane surface area. This study confirms the benefits of microalgae as a sustainable biocathode in microbial desalination cells (MDCs) to supply electron acceptors in an environmental-friendly manner. Compared to photosynthetic microbial desalination cells (PMDCs), the CPDC decreased the desalination time by a factor of about 4. Besides, the NaCl removal was about 69% for 12 g/L NaCl concentration in the CPDC, higher than other MDCs. In addition, as a new operational factor, the internal resistance variations were determined by electrochemical impedance spectroscopy in different case studies. The results demonstrated for the first time the possibility of applying a new desalination cell (i.e. CPDC) for water desalination and power generation which only uses a source of chemical reaction and microalgae photosynthesis without the need for an external power source. © 2021 Elsevier B.V.
Journal of Power Sources (03787753)462
The rapid growth of portable and wearable electronics have greatly stimulated simplified fabrication of energy storage devices, from which micro-supercapacitors (MSCs) are an ideal power source, due to high power density and long lifetime. However, the development of a simple and cost-effective procedure towards the fabrication of high-performance MSCs is still a challenge. To this end, here we report a self-patterned stamping process through pre-designed patterns (Fractal & Interdigital) on parafilm® coated polyethylene terephthalate (PET) substrate for the fabrication of a flexible and planar MSC. The imprinted patterns on parafilm® are filled by graphene oxide (GO)/carbon aerogel/MnO2 hybrid paste as a binder and additive-free active material, followed by GO reduction through a safe, low cost, and effective procedure using nascent hydrogen. In contrast to the hydrazine based reduction method, nascent hydrogen affords the integrity and stability to the active material without any peeling off from the substrate, with low ohmic resistance. The prepared MSCs display large capacitance and energy density of 8.7 mF cm−2 (43.66 F cm−3) and 6 mWh cm−3 for Interdigital electrode and 14.2 mF cm−2 (71.34 F cm−3) and 9.9 mWh cm−3 for Fractal electrode, respectively. Furthermore, the MSC displays capacitance retention of 85% after 25,000 cycles. The presented procedure is a simple and cost-effective strategy towards the fabrication of flexible MSCs with state-of-the-art performance. © 2020 Elsevier B.V.
Materials and Corrosion (15214176)69(4)pp. 472-480
Epoxy paint was homogeneously incorporated with Al2O3(α), Fe2O3(α), SiO2, and ZnO nanoparticles at 1, 2, and 3 wt% with respect to total weight of hardener and undried epoxy, and coated on carbon steel coupons. Corrosion protection performance of the samples was evaluated by linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in 3 wt% NaCl solution. Analysis of LSV data and thorough analysis of EIS data showed the beneficial effect of all types of nanoparticles at 1 wt%. For 2 and 3 wt% samples, performance was different, depending on the nanoparticle type. However, the sample containing 3 wt% Al2O3(α) showed the best performance among all the tested samples. The results were correlated to the ability of the nanoparticles to block corroding coatings by decreasing the porosity of the dried epoxy paint. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Materials Chemistry and Physics (02540584)203pp. 319-332
In this study, LiFePO4-C (LFP-C) nanocomposites are synthesized by ultrasonic spray pyrolysis technique followed by short calcination step, to apply as cathode active material of Li ion battery. 5.0 g of either table sugar, citric acid, and 2.5, 5.0, 7.5, and 10 g of sucrose are added to separate 100 ml solutions containing 0.2 M of LiNO3, Fe(NO3)3, and H3PO4, as starting solution. A carbon-free sample and an uncalcinated sample are also prepared. X-ray diffraction analysis revealed that the olivine phase is obtained only after calcination. SEM images show spherical morphology with micron and submicron sizes and features, as well as change in morphology and agglomeration, especially when carbon content of LFP-C is not enough. Calcination and addition of carbon-leaving species to the starting solution is proved to be vital for acceptable electrochemical performance. LFP-C sample derived from addition of 5 g sucrose to 100 ml of the starting solution shows the best electrochemical performance in terms of capacity, cyclability, capacity retention, and rate performance. © 2017 Elsevier B.V.
Solid State Ionics (01672738)320pp. 84-91
In this study, the effect of poly (vinylidene fluoride)/poly (vinyl acetate) (PVDF/PVAc) ratio in the cathode binder of the LiMn2O4 (LMO) electrode on the electrochemical performance of a rechargeable hybrid aqueous battery (ReHAB) is investigated. The miscibility of two polymers is confirmed by Furrier transform infrared (FTIR) and differential scanning calorimetry (DSC) measurements. The binary blends with different PVDF/PVAc ratios (100/0, 75/25, 50/50, 25/75 and 0/100) are used as binder for the LMO cathode preparation. It is found that incorporation of PVAc in the blend decreases the crystallinity of PVDF and increases the cathode hydrophilicity, leading to better wetting by the aqueous electrolyte. The morphology and electrochemical properties of the cathode are also studied. Electrochemical cyclic voltammogram, discharge capacity, capacity retention, electrochemical impedance and rate capability are investigated. It is concluded that the blend with a PVDF/PVAc ratio of 25/75 has the best cycle performance (80% capacity retention after 100 cycles at the rate of 1 °C), with 0.2 °C discharge capacity (110 mAh gr−1) and the best rate capability. © 2018 Elsevier B.V.
Analytical And Bioanalytical Electrochemistry (20084226)10(1)pp. 1-17
Lithium ion batteries are considered the most promising energy storage and conversion device candidates for use in future electric vehicle applications due to their ultrahigh energy density. In this study, a facile, ultrafast and green flame spray pyrolysis method was developed well to efficiently fabricate submicron-sized lithium cobaltite spheres from an aqueous spray solution of lithium nitrate and cobalt nitrate. Molar ratios of lithium: cobalt in the precursor solution was altered at three different levels, viz., 1: 1, 1.3: 1 and 1.7: 1. Then samples obtained under same conditions were calcined. Also, sample obtained with molar ratios of lithium: cobalt 1.7: 1, under different conditions atmosphere was calcined. The sample calcined in oxygen atmosphere with low flow was phase pure crystalline rhombohedral lithium cobalt oxide. Furthermore, this sample showed an acceptable performance as cathode active material of lithium ion battery. The rechargeable capacity was 162 mAh g-1 at 0.1 C and 101 mAh g-1 at 1 C and capacity retention of 84% after 50 cycles at this rate for this sample was observed. © 2018 by CEE (Center of Excellence in Electrochemistry).
Journal of Electroanalytical Chemistry (15726657)799pp. 206-212
The α-Fe2O3/reduced graphene oxide (α-Fe2O3/RGO) nanocomposite thin film was prepared by two steps electrodeposition method on the Fluorine doped Tin Oxide (FTO) coated glass substrate. The α-Fe2O3 and α-Fe2O3/RGO nanocomposite films were characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The thickness of the nanocomposite film was measured below 400 nm. The electrochromic properties of both α-Fe2O3 and α-Fe2O3/RGO nanocomposite films were studied by cyclic voltammetry, chronoamperometry and UV–Vis spectroscopy with the standard three-electrode configuration. The results showed that the α-Fe2O3/RGO thin film have higher optical modulation, faster switching time and better cycling performance compared with pure α-Fe2O3 film. Furthermore, the combination of reduced graphene oxide into iron oxide film enhanced the optical density (ΔOD) about 18% and raised the coloration efficiency (CE) from 18 to 35 cm2 C− 1, at the wavelength of 640 nm. The enhanced electrochromic performance is basically attributed to the incorporation of the RGO into α-Fe2O3 film. © 2017
Zomorodian esfahani, M.,
Aghaei, A.,
Khosravi, M.,
Bagheri, N.,
Khakpour, Z.,
Javaheri, M. New Journal of Chemistry (11440546)41(20)pp. 11731-11741
In the present study, hybrid nanostructures of porous Co3O4 nanoball/carbon aerogel were prepared via the in situ growth of Co3O4 nanoballs with nanosized uniform structures within the pores of a pre-synthesized atmospheric pressure-dried highly mesoporous carbon aerogel. The three-dimensional structure of the carbon aerogel with appropriate electrical conductivity, high specific surface area and mesopore volume enabled the fabrication of an electrode with appropriate electrochemical performance when combined with the porous Co3O4 nanoball. This Co3O4 nanoball/carbon aerogel hybrid nanostructure exhibits a large specific capacitance of 350 F g-1 at the current density of 1 A g-1 in 6 M KOH electrolyte in a three electrode system. Furthermore, due to its special nanostructure, this electrode exhibits an energy density of 23.82 W h kg-1 at power density of 95.96 W kg-1 in 6 M KOH and an energy density of 19.44 W h kg-1 at power density of 76.2 W kg-1 in 2 M KOH. Cycling in the potential range of 0.0 to 1 V at a current density of 1 A g-1 in a symmetrical configuration (two-electrode system) exhibits an ascending capacitance trend with 210% of capacity retention after 6000 cycles. These prominent performance characteristics demonstrate the promising role of the prepared hybrid nanostructure for supercapacitor applications. © 2017 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Hendi, A.,
Rahmani, H.,
Mostofinejad, D.,
Tavakolinia, A.,
Khosravi, M. Construction and Building Materials (09500618)152pp. 192-205
Combination of microsilica and nanosilica (colloidal silica) are considered to design a high strength self-consolidating concrete to resist in the sulfuric acid medium. Artificial intelligence was used to predict and compare the behavior of these two pozzolans in a sulfuric acid medium. Contour plots were used to investigate the products combination better. Thermogravimetric analysis (TGA) was also used to find the calcium hydroxide range while using these two pozzolans. TGA revealed that colloidal silica did not contribute to cement hydration within seven days of curing while a combination of them boosted calcium hydroxide consumption. The results show that more substitution of the pozzolans could lead to lower mass loss while nanosilica has marginal effect on the residual compressive strength. The results also revealed that 7 percent substitution of microsilica showed the same effect as 2 percent nanosilica replacement. © 2017 Elsevier Ltd
Bonyadinejad, G.,
Sarafraz, M.,
Khosravi, M.,
Ebrahimi, A.,
Taghavi-shahri, S.M.,
Nateghi, R.,
Rastaghi, S. Korean Journal of Chemical Engineering (19757220)33(1)pp. 189-196
The decolorization and degradation of the synthetic aqueous solution of the Acid Orange 10 (AO10) dye on Ti/PbO2 anode were investigated using the response surface methodology based on central composite design with three variables: current density, pH, and supporting electrolyte concentration. The Ti/PbO2 electrode was prepared by the electrochemical deposition method. The optimum conditions for AO10 decolorization in synthetic dye solution were electrolyte concentration of 117.04 mM, pH of 12.05, and current density of 73.64 mA cm−2. The results indicated that the most effective factor for AO10 degradation was current density. Furthermore, the color removal efficiency significantly increased with increasing current density. To measure AO10 mineralization under optimum conditions, the chemical oxygen demand (COD) and total organic carbon (TOC) removal were evaluated. Under these conditions, decolorization was completed and 63% removal was recorded for COD and 60% for TOC after 100 min of electrolysis. © 2016, Korean Institute of Chemical Engineers, Seoul, Korea.
Electrochimica Acta (00134686)203pp. 9-20
Nanoporous hard carbon microspheres (NHCSs) were prepared by combination of microemulsion and polymerization methods and using phenolic resin (resol) as precursor and ethanol and ethylene glycol (EG) as solvent and soft template, respectively, followed by carbonization process. Using different amounts of EG resulted in NHCSs with different crystalline structure, surface area and pore volumes, and Li ion storage capacity, as evidenced by physical and electrochemical measurements. Higher and lower polymerization rates were also tested on the starting resol solution with composition which led to the NHCS with the highest surface area and Li ion storage capacity. The sample polymerized at higher rate had the highest surface area and pore volume, as well as the best Li ion storage performance in terms of capacity and rate capability. for all of the NHCSs, the specific surface area and Li ion storage capacity were well correlated, and a good correlation was observed between total pore volume and rate capability. Furthermore, acceptable correlations were found between Li ion storage capacity and either surface area or microstructure of the NHCSs. © 2016 Elsevier Ltd. All rights reserved.
Bonyadinejad, G.,
Khosravi, M.,
Ebrahimi, A.,
Taghavi-shahri, S.M.,
Nateghi, R. International Journal of Environmental Health Engineering (22779183)5(1)
Aims: The sonoelectrochemical mineralization of the synthetic aqueous solution of the perfluorooctanoic acid (PFOA) on Ti/PbO2 anode was investigated using the response surface methodology based on a central composite design (CCD). Materials and Methods: The CCD was performed using three different variables such as current density (CD) (mA/cm2), pH, and supporting electrolyte (EL) concentration (mM). The total organic carbon (TOC) removal was determined as an indicator of PFOA mineralization. A Shimadzu TOC analyzer was used to measure the TOC of the samples. The Ti/PbO2 electrode was prepared using the electrochemical deposition method. In order to enhance the electrochemical mineralization, ultrasonic (US) radiation was used. The US frequency was 20 kHz. Results: The optimum conditions for PFOA mineralization in synthetic solution were EL concentration of 94 mM, pH of 2, and CD of 83.64 mA/cm2, which resulted in complete TOC removal. The results indicated that the most effective factor for PFOA mineralization was CD. Besides, the TOC removal efficiency significantly increased with increasing CD. Conclusions: Under optimum conditions, the mineralization of PFOA was almost completed after 90 min of sonoelectrolysis. Therefore, sonoelectrolysis was found to be a more effective technique for mineralization of an environmentally persistent compound. © 2016 Medknow. All rights reserved.
Sarafraz, M.,
Khosravi, M.,
Bonyadinejad, G.,
Ebrahimi, A.,
Taghavi-shahri, S.M. International Journal of Environmental Health Engineering (22779183)4(2)
Aims: The aim of this study was decolorization of the synthetic aqueous solution of the acid orange 10 (AO10) dye on Ti/SnO2-Sb anode using the response surface methodology based on central composite design. Materials and Methods: The Ti/SnO2-Sb electrode was prepared using the standard thermal decomposition method and three variables: Current density (CD), pH, and supporting electrolyte concentration were assessed. The dye decoloration was monitored spectrophotometrically by measuring the absorbance of the remaining dye at the maximum absorption wavelength (λmax) of 475 nm on a ultraviolet-visible spectrophotometer. To measure AO10 mineralization under optimum conditions, chemical oxygen demand (COD) and total organic carbon (TOC) removal also were evaluated. Results: It was found by the model prediction, minimum dye decolorization was 39% (CD = 6 and pH = 7.5) and maximum dye decolorization was 101% (CD = 65 and pH = 2). Thus, the optimum conditions for AO10 decolorization in synthetic dye solution were electrolyte concentration of 75 mM/L, pH of 2, and CD of 65 mA/cm. Under optimum conditions, decolorization of 100 mg/L dye was complete, and 61.3% and 43.9% COD and TOC removal were recorded after 50 min of electrolysis, respectively. Conclusion: High-efficiency electrochemical degradation of AO10 was achieved over Ti/SnO2-Sb anode as a model electrode. It was concluded that the most effective factor for AO10 decolorization was CD. The electrochemical degradation using Ti/SnO2-Sb electrode is a suitable and an environmentfriendly method for the degradation of refractory dyes in aqueous solution. © 2015 Sarafraz M.
Bonyadinejad, G.,
Khosravi, M.,
Ebrahimi, A.,
Nateghi, R.,
Taghavi-shahri, S.M.,
Mohammadi, H. Journal Of Environmental Health Science And Engineering (2052336X)13(1)
Background: Perfluorocarboxylic acids (PFCAs) are emerging pollutant and classified as fully fluorinated hydrocarbons containing a carboxylic group. PFCAs show intensively resistance against chemical and biological degradation due to their strong C-F bond. The Sonoelectrochemical mineralization of the synthetic aqueous solution of the perfluorooctanoic acid (PFOA) on Ti/PbO2 anode was investigated using the response surface methodology based on a central composite design with three variables: current density, pH, and supporting electrolyte concentration. Methods: The defluorination ratio of PFOA was determined as an indicator of PFOA mineralization. Fluoride ion concentration was measured with an ion chromatograph unit. The Ti/PbO2 electrode was prepared using the electrochemical deposition method. The ultrasonic frequency was 20 kHz. Results: The optimum conditions for PFOA mineralization in synthetic solution were electrolyte concentration, pH, and current density of 94 mM, 2, and 83.64 mA/cm2, respectively. The results indicated that the most effective factor for PFOA mineralization was current density. Furthermore, the PFOA defluorination efficiency significantly enhanced with increasing current density. Under optimum conditions, the maximum mineralization of PFOA was 95.48 % after 90 min of sonoelectrolysis. Conclusions: Sonoelectrolysis was found to be a more effective technique for mineralization of an environmentally persistent compound. © 2015 Bonyadinejad et al.
Nasr-esfahani, M.,
Zendehdel, M.,
Yaghoobi nia, N.,
Jafari, B.,
Khosravi, M. RSC Advances (20462069)4(31)pp. 15961-15967
One-electron fast redox mediators like cobalt complexes are a new important class of mediator system in dye sensitized solar cells (DSCs) that have some special features such as fast regeneration reactions, low absorption in the visible light range without the occurrence of destructive reactions with the materials of the DSCs. In this research, for the first time, a new Schiff base cobalt complex has been synthesized and used as an efficient redox mediator system in dye sensitized solar cells which are fabricated using D35 organic dye as a sensitizer and mesoporous nanostructured titania as a photoanode. J-V measurements of the prepared DSC were carried out under AM1.5G irradiation and photoelectrochemical parameters like the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), voltage decay and the overall efficiency were measured and compared to the conventional symmetric cobalt polypyridine complexes. The J-V curve results show enhancement of the open-circuit voltage in the DSC with the new Schiff base cobalt complex mediator compared with classic polypyridine cobalt complexes. Comparison between the dark currents of the investigated cells provides qualitative information about the electron recombination process. Lower dark currents were observed in DSCs with a titania blocking layer. Voltage decay measurements, the calculated electron lifetime and the effective recombination order (β) show lower average β values for the DSC with the Schiff base cobalt complex as a redox mediator. This journal is © the Partner Organisations 2014.
Advanced Materials Research (discontinued) (16628985)829pp. 922-926
Hard carbon (HC) is a kind of carbon that is difficult to be graphitized and usually is fabricated from pyrolysis of polymers such as phenolic resins, epoxy resins and pitch. From the structural point of view, HC is highly irregular and disordered, and primarily consists of single-layered carbon atoms that are closely and randomly connected. In this work, a sample of HC was synthesized through pyrolysis of oxidized pitch at high temperature (800 °C) under nitrogen atmosphere. XRD analysis demonstrated that the HC has higher d-spacing and lower stacking height than graphite. Elemental analysis showed that the synthesized HC have the [H]/[C] atomic ratio of 0.22. Electrochemical tests showed this non-graphitized carbon has higher capacity (600 mAhg-1) than the theoretically maximum capacity of 372 mAhg-1 for C6Li, indicating that the ratio of Li to C atoms is higher than 1/6 and the produced HC is suitable as anode material for Lithium ion battery. © (2014) Trans Tech Publications, Switzerland.
Mirabbaszadeh k., ,
Ahmadi m., ,
Khosravi, M.,
Mokhtari, R.,
Salari s., Journal of Inorganic and Organometallic Polymers and Materials (15741443)23(6)pp. 1219-1225
Single crystalline cesium-doped ZnO nanorods with homogeneous size and shape were hydrothermally grown on Cs-ZnO nucleated glass substrate. The effect of hydrothermal growth duration on the characteristics of Cs-doped ZnO nanorods was examined. The samples were analyzed by X-ray diffraction (XRD), energy dispersive X-ray analysis, scanning electron microscopy, and electrical conductivity, optical transmission and photoluminescence (PL) measurements. XRD analysis showed that Cs-doped ZnO nanorods are wurtzite single crystals and are grown preferentially along the c-axis. Elemental analysis confirmed the presence of 1 at.% of Cs, according to the composition of growth solution. Electrical conductivity of typical samples showed higher values for the 1 at.%-doped sample, which confirmed incorporation of the Cs dopant. The samples were optically transparent and showed two UV and visible PL peaks from which the former peak experienced a red shift and a pronounced increase in intensity with increasing growth time. The fabricated Cs-doped ZnO nanorods are suitable candidates for applications as excitonic solar cells due to their ease of fabrication, morphology control and optical properties. © 2013 Springer Science+Business Media New York.
Journal of Luminescence (00222313)137pp. 230-236
Nanocrystalline of BaSO4 and BaSO4:Dy,Tb of grain size 45-55 nm has been prepared by the co-precipitation method and its thermoluminescence characteristics have been studied. The formation of the material was confirmed by the X-ray diffraction (XRD) and UV-visible spectroscopy. Shape and size of the prepared nanocrystalline powder was observed by a scanning electron microscope (SEM). The TL glow curve of the nanocrystalline pellets of BaSO4:Dy,Tb shows a prominent single peak at 530 K along with another peak of lesser intensity at around 420 K and 560 K. On the contrary, the nanocrystalline pellets of BaSO4 show a peak of low intensity at 500 K and prominent peak around 460 K. The glow curve structure does not change at the range of 0.1-15 kGy and some new peaks appear at high doses but have low intensities. The 530 K of the nanocrystalline pellets of BaSO4:Dy,Tb shows a linear response with exposure increasing up to very high values (as high as 7 kGy), where the other doped BaSO4 show saturation. © 2013 Elsevier B.V.
International Journal of Hydrogen Energy (03603199)35(19)pp. 10527-10538
Through a simple and rapid method, carbon papers (CPs) were coated with Au and the resulting Au/CP substrates were used for the preparation of Pt/Au/CP by Cu underpotential deposition (Cu UPD) and redox replacement technique. A series of Ptn/Au/CP catalysts (where n = number of UPD-redox replacement cycles) were synthesized and their electrochemical properties for methanol oxidation reaction (MOR), and oxygen reduction reaction (ORR) were investigated by electrochemical measurements. The Ptn/Au/CP electrodes show higher electrocatalytic activity and enhanced poison tolerance for the MOR as compared to a commercial Pt/C on CP (Pt/C/CP). The highest mass specific activity and Pt utilization efficiency for MOR was observed on Pt1/Au/CP with a thickness close to a monatomic Pt layer. Chronoamperometric tests in methanol solution revealed that Ptn/Au/CPs have much higher CO tolerance compared to Pt/C/CP. Among the Ptn/Au/CPs, CO tolerance decreases with increasing the amount of deposited Pt, indicating that the exposed Au atoms in close proximity to Pt plays a positive role against CO poisoning. Compared with the Pt/C/CP, all the Ptn/Au/CP electrodes show more positive onset potentials and lower overpotentials for ORR. For instance, the onset potential of ORR is 150 mV more positive and the overpotential is ∼140 mV lower on Pt4/Au/CP with respect to Pt/C/CP. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.
Carbon (00086223)48(11)pp. 3131-3138
We developed a simple, rapid and highly efficient flame synthesis method for direct growing carbon nanofibers (CNFs) on carbon paper (CP) using a common laboratory ethanol flame as both heat and carbon sources. High density CNFs with tangled solid-cored structure were uniformly formed over the Ni-plated CP surface in ~20 s. The morphologies of the CNFs were characterized by scanning electron microscopy and transmission electron microscopy. X-ray diffraction study revealed the graphitic nature of the CNFs. Raman spectroscopy analysis confirmed that the CNFs are disordered graphitic nanocrystallites with high degree of exposed edges. Electrochemical impedance spectroscopy and cyclic voltammetry were used to show that growing CNFs directly on CP facilitates electron transfer with concomitant increase in double-layer capacitance. The CNF/CP was used as support for Pt nanoparticles to study their supporting effect on the catalyst performance. The as prepared Pt/CNF electrocatalyst exhibited much improved electrocatalytic activity for methanol oxidation compared to Pt/CP and commercial Pt/C on CP. High electronic conductivity and improved electrochemical behavior of the CNF/CPs, resulted from direct contact of the nanofibers with CP, combined with unique properties of CNFs, make the synthesized CNF/CPs promising for fuel cell applications. © 2010 Elsevier Ltd. All rights reserved.
Zeitschrift fur Naturforschung - Section B Journal of Chemical Sciences (09320776)62(8)pp. 1030-1034
Catalytic ring opening reactions of α-epoxyketones by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in methanol solution at r. t. and under reflux conditions resulted in the formation of α-hydroxy-β- methoxyketones through Cβ-O bond cleavage in excellent yields. Whereas the type and nature of the additional substituent affects the rate of ring opening, the effect of temperature has an extreme influence on the rate of reactions. Cyclic voltammetric studies of DDQ at 15°C and 33°C support the increased electron-acceptor ability of DDQ by the increasing of temperature. © 2007 Verlag der Zeitschrift für Naturforschung.
Electrochimica Acta (00134686)52(24)pp. 7051-7060
Comparative electrochemical behavior of self-assembled monolayers (SAMs) of three heteroaromatic thiols, 2-mercaptobenzoxazole (MBO), 2-mercaptobenzothiazole (MBT), and 2-mercaptobenzimidazole (MBI) are investigated by means of cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The electrochemical characteristics of the electrode/solution interface are considerably and differently affected by thiols constructing the SAMs. The consumed charges for reductive desorption of SAMs, which is criterion for the amount of chemically adsorbed thiol, are significantly different for these three SAMs, specially for MBT, implying that SAM of MBT is formed through both sulfur atoms; the thiol sulfur and skeleton sulfur of the thiazole ring. Desorption potentials of the SAMs have shown the following order for strength of gold-sulfur bond: MBT > MBO > MBI. Activity of the three SAMs as pH-sensitive interfaces was also investigated and their surface-pKa values derived from the EIS measurements showed this order for acidic strength of SAMs: MBO > MBT > MBI. This is the same order expected due to the difference in electronegativity of the O, S, and N heteroatoms, and confirms that the most electron-rich ring imidazole is attached to the benzene ring of MBI. A comparison of the interfacial charge transfer resistance variation as a function of gold immersion time in thiols solution reveals that kinetics of Au-MBT assembly is different from those of two others and confirms formation of Au-MBT SAM via both sulfur atoms of MBT. © 2007 Elsevier Ltd. All rights reserved.
