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    Enhanced electrochemical activity of Co3O4/Co9S8 heterostructure catalyst for water splitting

    , Article International Journal of Hydrogen Energy ; 2021 ; 03603199 (ISSN) Khan, N. A ; Ahmad, I ; Rashid, N ; Zafar, M. N ; Shehzad, F. K ; ullah, Z ; Ul-Hamid, A ; Nazar, M.F ; Junaid, M ; Faheem, M ; Shafqat, S. S ; Jabeen, U ; Dahshan, A ; Sharif University of Technology
    Elsevier Ltd  2021
    The dearth of efficient, robust, and economical electrocatalysts for water oxidation is dubiously the key obstacle for renewable energy devices, so synthesis of efficient, and cost-effective metal-based water oxidation catalysts is vital. Herein, Co3O4, Co9S8 catalysts and their heterostructure Co3O4/Co9S8 were synthesized and evaluated as water oxidation electrocatalysts. The characterization of Co3O4, Co9S8, and Co3O4/Co9S8 electrocatalysts was performed using Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction techniques. The heterostructure Co3O4/Co9S8 (1.46 V) exhibited water oxidation electrocatalysis at extremely low onset potential compared to... 

    Synthesis, characterization, crystal structure and oxygen-evolution activity of a manganese(II) complex with 2,4,6-tris (2-pyridyl)-1,3,5-triazine

    , Article Polyhedron ; Volume 29, Issue 17 , 2010 , Pages 3246-3250 ; 02775387 (ISSN) Najafpour, M. M ; Boghaei, D. M ; McKee, V ; Sharif University of Technology
    The title complex [Mn(tptz)(CH3COO)(OH2) 2]NO3 was synthesized through the reaction of tptz (2,4,6-tris(2-pyridyl)-1,3,5-triazine), nitric acid and manganese(II) acetate. The molecular structure was characterized by X-ray diffraction, elemental analysis, electrochemistry, EPR, IR, fluorescence and UV-Vis spectroscopy and its oxygen evolving activity has been studied. X-ray structure analysis shows that each Mn(II) ion is seven coordinated by a bidentate acetate, three nitrogen atoms of tptz and two oxygen atoms from two water ligands, which are coordinated in axial positions. The complex acts as an oxygen evolving complex with oxone (2KHSO5·KHSO4·K 2SO4) as primary oxidant in aqueous... 

    RGO-α-Fe2O3/β-FeOOH ternary heterostructure with urchin-like morphology for efficient oxygen evolution reaction

    , Article Journal of Electroanalytical Chemistry ; Volume 843 , 2019 , Pages 1-11 ; 15726657 (ISSN) Bazri, B ; Kowsari, E ; Seifvand, N ; Naseri, N ; Sharif University of Technology
    Elsevier B.V  2019
    RGO-α-Fe2O3/β-FeOOH ternary heterostructure composite has been developed as an active photocatalyst for photoelectrochemical water splitting. RGO-α-Fe2O3/β-FeOOH has been successfully synthesized through one-pot hydrothermal-ionic liquid assisted route using tetrabutyl ammonium L-methioninate [TBA][L-Met]and graphene oxide (GO). The electrochemical studies were carried out to demonstrate the oxygen evolution reaction (OER)and photocatalytic activities. The overpotential reduction by rGO-α-Fe2O3/β-FeOOH sample was higher than the nanobean α-Fe2O3/β-FeOOH and pristine α-Fe2O3 samples. The photocurrent density enhanced for rGO-α-Fe2O3/β–FeOOH urchin-like structure and obtained as 0.62 mA·cm−2.... 

    Kinetics Investigation of Oxygen Evolution from Water Oxidation in the Presence of Bismuth Vanadate Nanocatalysts

    , M.Sc. Thesis Sharif University of Technology Moradpour, Amin (Author) ; Rahman Setayesh, Shahrbanoo (Supervisor)
    In this project, BiVO4 , Mn3O4 and BiVO4- Mn3O4 nanocatalysts were synthesized using the hydrothermal method. The properties of these nanocatalysts were determined by XRD, SEM, FT-IR, DRS, PL, ICP, EDX, BET and AA techniques. Analysys XRD patterns and SEM images of samples confirmed monoclinic structure for BiVO4 and tetragonal structure for Mn3O4. The DRS and PL spectra showed adctrease in the band gap and electron – hole pair recombination for BM 60:40 relative to BiVO4. Oxygen production was studied in the presence of different percentages of BiVO4 and Mn3O4 in BiVO4 - Mn3O4 nanocomposite and was observed that the 60:40 wt.% (Bismuth vanadate 60% and manganese oxide 40%) produced more... 

    Mesoporous nanostructured composite derived from thermal treatment CoFe prussian blue analogue cages and electrodeposited NiCo-S as an efficient electrocatalyst for an oxygen evolution reaction

    , Article ACS Applied Materials and Interfaces ; Volume 12, Issue 14 , 2020 , Pages 16250-16263 Hafezi Kahnamouei, M ; Shahrokhian, S ; Sharif University of Technology
    American Chemical Society  2020
    Developing effective and priceless electrocatalysts is an indispensable requirement for advancing the efficiency of water splitting to get clean and sustainable fuels. Herein, we reported a feasible strategy for preparing a trimetallic (NiCoFe) superior electrocatalyst with a novel open-cage/3D frame-like structure for an oxygen evolution reaction (OER). It is prepared by consequent thermal treatments of a CoFe Prussian blue analogue frame/cage-like structure under an argon (CoFeA-TT) atmosphere and then electrochemical deposition of nickel-cobalt sulfide nanosheets as a shell layer on it. The electrochemical measurements demonstrated that the deposition of NiCo-S on CoFeA-TT... 

    Shape-controlled synthesis of thorn-like 1D phosphorized Co supported by Ni foam electrocatalysts for overall water splitting

    , Article Journal of Materials Science: Materials in Electronics ; Volume 32, Issue 13 , 2021 , Pages 18363-18370 ; 09574522 (ISSN) Nourmohammadi, Khiarak, B ; Asaadi Zahraei, A ; Nazarzadeh, K ; Akbari Hasanjani, H. R ; Mohammadzadeh, H ; Sharif University of Technology
    Springer  2021
    A cost-effective, durable, and easy-to-produce improvement in bifunctional electrocatalysts for water splitting is crucial for future renewable energy systems. In this present study, shape-controlled one-dimensional (1D) phosphorized cobalt (CoP) on 3D porous nickel foam (NiF) was synthesized through successive treatment of commercial NiF with acetone and ethanol, followed by hydrothermal growth of Co and final process of phosphorization by thermochemical reactions. The evaluations of products proved reduced overpotential (270 mV at 10 mA. cm−2 for hydrogen evolution reaction (HER) process and a low overpotential of 320 mV to reach a high current density of 20 mA. cm−2), low Tafel slope... 

    Metal-organic framework derived NiSe2/CeO2nanocomposite as a high-performance electrocatalyst for oxygen evolution reaction (OER)

    , Article Sustainable Energy and Fuels ; Volume 5, Issue 11 , 2021 , Pages 2994-3000 ; 23984902 (ISSN) Taherinia, D ; Moravvej, S. H ; Moazzeni, M ; Akbarzadeh, E ; Sharif University of Technology
    Royal Society of Chemistry  2021
    The development of efficient and cost-effective catalysts for the oxygen evolution reaction is highly desirable for applications that are based on sustainable and clean technologies. In this study, we report the synthesis of a series of cerium(iv) oxide and nickel diselenide nanocomposites (NiSe2/CeO2) as efficient electrocatalysts for the oxygen evolution reaction in an alkaline medium. The ratios of the two substances were optimized to reach the highest catalytic activity. The structure and morphology of synthesized materials were investigated by XRD, FE-SEM, EDX, BET, XPS, and TEM techniques. It was observed that the nanocomposite with a 10 : 1 mass ratio of NiSe2to CeO2showed the best... 

    Effect of a synthesized pulsed electrodeposited Tin/pbo2-ruo2nanocomposite on zinc electrowinning

    , Article Industrial and Engineering Chemistry Research ; Volume 60, Issue 31 , 2021 , Pages 11737-11748 ; 08885885 (ISSN) Hakimi, F ; Rashchi, F ; Ghalekhani, M ; Dolati, A ; Razi Astaraei, F ; Sharif University of Technology
    American Chemical Society  2021
    Nowadays, there is a growing interest in synthesizing electrodes used in zinc electrowinning, increasing active surface area, decreasing specific energy consumption, and the oxygen evolution reaction (OER) overpotential. In this study, modified nanocomposite anodes were synthesized by applying pulsed and constant direct current electrodeposition to improve the catalytic activity of the electrodes toward the oxygen evolution reaction (OER) and reduce energy consumption in zinc electrowinning. By decreasing particle size, the active surface area of PbO2-RuO2 nano-mixed composite electrode was 2.88 and 14.22 times greater than PbO2-RuO2 microcomposite and pure PbO2 electrodes, respectively.... 

    Mesoporous nanostructures of NiCo-LDH/ZnCo2O4 as an efficient electrocatalyst for oxygen evolution reaction

    , Article Journal of Colloid and Interface Science ; Volume 604 , 2021 , Pages 832-843 ; 00219797 (ISSN) Shamloofard, M ; Shahrokhian, S ; Amini, M. K ; Sharif University of Technology
    Academic Press Inc  2021
    Increasing energy demands for pollution-free and renewable energy technologies have stimulated intense research on the development of inexpensive, highly efficient, and stable non-noble metal electrocatalysts for oxygen evolution reaction (OER). In this study, a superior OER performance was achieved using a tri-metallic (Zn, Co, Ni) high-performance electrocatalyst. We successfully fabricated a peony-flower-like hierarchical ZnCo2O4 through an additive-free hydrothermal reaction followed by heat treatment. Then NiCo-LDH (layered double hydroxides) nano-flakes was electrodeposited on the ZnCo2O4/GCE surface to prepare NiCo-LDH/ZnCo2O4/GCE which was used as electrode for OER. The structure and... 

    Investigation of the Effect of Various Electrolyte Additives to Increase the Overpotential of the Hydrogen and Oxygen Evolution Reactions in Lead-Acid Batteries

    , M.Sc. Thesis Sharif University of Technology Mohammadvand, Ali (Author) ; Taherinia, Davood (Supervisor)
    Lead-acid batteries have been used for over 150 years as a reliable means of storing electrical energy. These batteries have a variety of applications due to their high safety, reliable performance, and relatively easy manufacturing process, including in car starters, car lighting and combustion, electric vehicles (especially electric bicycles), and the resulting electrical energy storage. From renewable sources or pulsed power supplies in hybrid electric vehicles. Despite increasing advances in the performance and design of these batteries, there are still problems in this area. One of the most important of these is the electrolysis of water as a side reaction, which leads to the production... 

    Heterogeneous water oxidation by bidentate schiff base manganese complexes in the presence of cerium(IV) ammonium nitrate

    , Article Transition Metal Chemistry ; Volume 34, Issue 4 , 2009 , Pages 367-372 ; 03404285 (ISSN) Najafpour, M. M ; Boghaei, D. M ; Sharif University of Technology
    Oxygen evolution was observed upon mixing solid manganese(III) bidentate Schiff base complexes with aqueous solutions of cerium(IV) ammonium nitrate. However, oxygen evolution was not observed upon mixing solutions of the complexes (in acetonitrile) with Ce(IV). Electron-withdrawing substituents on the Schiff base ligands (NO2, Br) enhanced the reactivity of the manganese complexes toward oxygen evolution. Oxygen evolution was also affected by R groups on the ligands, in the order Me > Et Bz. © 2009 Springer Science+Business Media B.V  

    Efficient electrocatalytic oxidation of water and glucose on dendritic-shaped multicomponent transition metals/spongy graphene composites

    , Article Electrochimica Acta ; Volume 386 , 2021 ; 00134686 (ISSN) Nourmohammadi Khiarak, B ; Mohammadi, R ; Mojaddami, M ; Rahmati, R ; Hemmati, A ; Simchi, A ; Sharif University of Technology
    Elsevier Ltd  2021
    To improve the efficiency of electrochemical processes for environmental remediation, we present a new type of hybrid nanomaterials based on leaf-like copper-based quaternary transition metals and spongy monolayer graphene. To demonstrate the functionality of the hybrid electrocatalyst, fast and competent electrooxidation of water and glucose is shown. The mechanism of improved catalysis is ascribed to the synergetic catalytic effect of quaternary Cu-Ni-Fe-Co alloy with dendritic morphology along with the highly conductive and spongy structure of the graphene monolayer. It is shown that water oxidation can be performed at a low overpotential of 315 mV to reach a current denisty of 100 mA... 

    3D self-supporting mixed transition metal oxysulfide nanowires on porous graphene networks for oxygen evolution reaction in alkaline solution

    , Article Journal of Electroanalytical Chemistry ; Volume 893 , 2021 ; 15726657 (ISSN) Nourmohammadi Khiarak, B ; Mohammadi, R ; Mojaddami, M ; Mohandes, F ; Simchi, A ; Sharif University of Technology
    Elsevier B.V  2021
    Precious metal-free electrocatalysts based on two-dimensional nanomaterials have efficiently been used for oxygen evolution reaction; however, the low activity and stability of these materials as compared with noble metals are still distractive. We present a novel and high-performance electrocatalyst based on nanowires of mixed transition metal oxysulfide supported by three-dimensional highly porous graphene networks. Electrochemical studies indicated that the high electron transport medium of nanowires and bilayer graphene nanosheets as well as their high active surface area promote the kinetics of oxygen evolution reaction (OER). A quite small overpotential of 260 mV at the current density... 

    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) Asen, P ; Esfandiar, A ; Sharif University of Technology
    Elsevier Ltd  2021
    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... 

    Investigaion Properties of Electrocatalytic Transition Metal Chalcogenids Nanocomposite in Hydrogen and Oxygen Evolution Reactions

    , M.Sc. Thesis Sharif University of Technology Moazzeni, Mohammad (Author) ; Taherinia, Davood (Supervisor)
    Electrochemical water splitting which consists of two half-reactions, namely; the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), is an important process in electrochemical energy storage and sustainable production of energy. Therefore, the development of cost-effective and efficient electrocatalysts for water splitting has attracted a lot of interest. In this work, a new nanocomposite was prepared from cobalt diselenide and cerium (IV) oxide derived from calcination of a cerium-based metal-organic framework (Ce-MOF), via hydrothermal and electrodeposition methods. The structure and morphology of synthesized materials were investigated by XRD, FE-SEM, EDX, and BET... 

    Synthesis, characterization, DFT studies and catalytic activities of manganese(ii) complex with 1,4-bis(2,2′:6,2′′-terpyridin- 4′-yl) benzene

    , Article Dalton Transactions ; Volume 41, Issue 39 , Jul , 2012 , Pages 12282-12288 ; 14779226 (ISSN) Najafpour, M. M ; Hillier, W ; Shamkhali, A. N ; Amini, M ; Beckmann, K ; Jagličić, Z ; Jagodič, M ; Strauch, P ; Moghaddam, A. N ; Beretta, G ; Bagherzadeh, M ; Sharif University of Technology
    A new di-manganese complex with "back-to-back" 1,4-bis(2,2′:6,2′′-terpyridin-4′-yl) benzene ligation has been synthesized and characterised by a variety of techniques. The back-to-back ligation presents a novel new mononuclear manganese catalytic centre that functions as a heterogeneous catalysis for the evolution of oxygen in the presence of an exogenous oxidant. We discuss the synthesis and spectroscopic characterizations of this complex and propose a mechanism for oxygen evolution activity of the compound in the presence of oxone. The di-manganese complex also shows efficient and selective catalytic oxidation of sulfides in the presence of H2O2. Density functional theory calculations were... 

    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) Naseri, N ; Esfandiar, A ; Qorbani, M ; Moshfegh, A. Z ; Sharif University of Technology
    American Chemical Society  2016
    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... 

    First-principles study on ZnV2O6 and Zn2V2O7: two new photoanode candidates for photoelectrochemical water oxidation

    , Article Ceramics International ; Volume 44, Issue 6 , 2018 , Pages 6607-6613 ; 02728842 (ISSN) Sameie, H ; Sabbagh Alvani, A. A ; Naseri, N ; Du, S ; Rosei, F ; Sharif University of Technology
    Elsevier Ltd  2018
    We used first principles calculations based on density functional theory with generalized gradient approximation to investigate and compare the structural, electronic and optical properties of two photoanode materials, ZnV2O6 and Zn2V2O7, for use in photocatalytic water splitting. After geometry optimization, the calculated structural parameters evince a satisfactory agreement with the reported experimental results indicating that the used method and conditions are suitable. The electronic structures demonstrate that both photocatalysts possess favorable band gaps (2.31 and 2.52 eV) and appropriate band edge positions for oxygen evolution reaction under solar radiation. The relatively light... 

    Self-supported nanoporous Zn–Ni–Co/Cu selenides microball arrays for hybrid energy storage and electrocatalytic water/urea splitting

    , Article Chemical Engineering Journal ; Volume 375 , 2019 ; 13858947 (ISSN) Hosseini, H ; Shahrokhian, S ; Sharif University of Technology
    Elsevier B.V  2019
    The phase-pure multiple ternary or quaternary metal selenides in energy boosting, have not been reported yet. Here, self-supported porous crystalline Zn–Ni–Co/Cu selenides microballs arrays were constructed by selenation of the designed tubular Cu(OH)2 arrays decorated with ultrathin Zn–Co–Ni tri-metallic hydroxide on carbon cloth substrate. For this rational engineering, a novel precursor sample was firstly prepared by conversion of deposited Cu layer to hollow tubular Cu(OH)2 arrays on carbon cloth, then, Zn-Co–Ni layered ternary hydroxides with a thin layer structure was deposited around this tubular arrays. The selenation with an exciting morphology change from amorphous tube to highly... 

    Simply tuned and sustainable cobalt oxide decorated titania nanotubes for photoelectrochemical water splitting

    , Article Applied Surface Science ; Volume 464 , 2019 , Pages 68-77 ; 01694332 (ISSN) Qarechalloo, S ; Naseri, N ; Salehi, F ; Moshfegh, A. Z ; Sharif University of Technology
    Elsevier B.V  2019
    Effective utilization of solar energy is an urgent global issue for solving current environmental problems and the energy crisis. A challenging issue in water splitting for solar fuel production is developing high performance and scalable photo/electro catalysts using low cost approach. Here, CoO x nanostructures were grown on anodized TiO 2 nanotube arrays (TNAs) by amperostatic electrodeposition method as oxygen evolution reaction (OER) photoanodes. The effects of electrodeposition current density and deposition time on the growth of so-called nanostructures were investigated based on photoelectrochemical (PEC) measurements and structural characterizations. X-ray diffraction patterns of...