Combined voltammetric and spectroscopic investigation of binding interaction between nifedipine and human serum albumin on polyelectrolyte modified ITO electrode

WOS: 000329531100069The binding interaction between the drug molecule, nifedipine (Nf), and the human serum albumin (HSA) on polyelectrolyte modified indium tin oxide (ITO) electrode has been investigated by the combination of electrochemical and fluorescence spectroscopy techniques. Surface modification has also been characterized by scanning electron microscopy (SEM) and Contact Angle (CA) measurements in each step. The cyclic voltammetry, electrochemical impedance parameters (peak potential difference (Delta E-p)), peak current difference (Delta I-p) and charge-transfer resistance (R-ct) indicate that nifedipine strongly interacted with human serum albumin molecule on the polyelectrolyte modified ITO electrode surface. Stern-Volmer quenching constant K-a is inversely correlated with the temperature, which indicates that the probable quenching mechanism of the nifedipine-human serum albumin binding reaction is initiated by complex formation. The results obtained from these techniques showed that Nf could bind to HSA. The binding constant (K-b) and the number of binding sites (n) of the drug with HSA at different temperatures were determined. At 298 K, K-b was found as 4.04 x 10(-3) and n was 1.08 for Nf-HSA. According to the van't Hoff equation, the thermodynamic parameters, Delta G, Delta H and Delta S, were obtained, showing the involvement of hydrophobic and electrostatic force in this interaction. (C) 2013 Elsevier Ltd. All rights reserved.Research Foundation of Selcuk University (BAP)We would like to thank The Research Foundation of Selcuk University (BAP) for financial support of this work

Photocatalytic hydrogen evolution reaction activity comparable to 1-D nanofiber materials exhibited by the kesterite nanorods catalysts

WOS:000518874500039Copper-based earth-abundant chalcogenides (kesterite) such as Cu2CoSnS4 and Cu2NiSnS4 are important class due to their outstanding performance and earth-abundant composition. Here, we have successfully synthesized Cu2CoSnS4, Cu2CoSnS4 and Cu2ZnSnS4 nanorods by a hot-injection technique. The photocatalytic hydrogen production activities of rod-like Cu2XSnS4 (X = Co, Ni and Zn) catalysts have been investigated by using electron donor triethanolamine and photosensitizer eosin-Y under visible-light irradiation. The hydrogen evolution rates for the nanorods change in the order of Cu2NiSnS4> Cu2CoSnS4> Cu2CoSnS4 (5117 mu molg(-1)h(-1), 1342 mu molg(-1)h(-1) and 719 mu molg(-1)h(-1)) respectively. The hydrogen evolution activities of Cu2XSnS4 nanorods have been compared to that of nanofiber and nanodot forms of Cu2XSnS4 catalysts. Cu2XSnS4 nanorods have been showed comparable photocatalytic activity for the hydrogen evolution compared with 1-D nanofiber Cu2XSnS4 catalysts. (C) 2020 Elsevier Ltd. All rights reserved.We gratefully acknowledge the financial support provided by The Scientific and Technological Research Council of Turkey (TUBITAK) under project number 217M212. Additionally, we are deeply grateful to Scientific and Technological Research & Application Center (BILTEM), Karamanoglu Mehmetbey University for collaborational work

Dye-sensitized photocatalytic hydrogen evolution by using copper-based ternary refractory metal chalcogenides

WOS:000537646100016The exploration of photocatalytic transformation of solar energy into H-2 through water splitting is an important direction towards sustainable and non-polluting energy in order to cover energy necessity partially. Ternary transition metal chalcogenides have been attracted attention among the other chalcogenides due to their potential applications in the photocatalytic and electrocatalytic hydrogen evolution. Herein, Cu2WS4 nanocubes and Cu2WSe4 nanosheets have been synthesized through a facile hot-injection method to benefit from the advantages such as minimizing the required pressure and reaction time by this technique. The photocatalytic hydrogen evolution activities of Cu2WS4 and Cu2WSe4 have been investigated under the visible light irradiation by using eosin-Y (EY) dye and triethanolamine (TEOA) as a photosensitizer and an electron donor, respectively. Cu2WS4 nanocubes have exhibited higher photocatalytic activity and stability than Cu2WSe4 nanosheets. The photocatalytic HER rates of Cu2WS4 and Cu2WSe4 have been determined as 1260 mu mol g(-1) h(-1) and 861 mu mol g(-1) h(-1), respectively. Photocatalytic HER activities were figured out in the order of Cu2WS4 > Cu2WSe4 which could be attributed to differences between proton reduction potential and the conduction band energy levels.The exploration of photocatalytic transformation of solar energy into H-2 through water splitting is an important direction towards sustainable and non-polluting energy in order to cover energy necessity partially. Ternary transition metal chalcogenides have been attracted attention among the other chalcogenides due to their potential applications in the photocatalytic and electrocatalytic hydrogen evolution. Herein, Cu2WS4 nanocubes and Cu2WSe4 nanosheets have been synthesized through a facile hot-injection method to benefit from the advantages such as minimizing the required pressure and reaction time by this technique. The photocatalytic hydrogen evolution activities of Cu2WS4 and Cu2WSe4 have been investigated under the visible light irradiation by using eosin-Y (EY) dye and triethanolamine (TEOA) as a photosensitizer and an electron donor, respectively. Cu2WS4 nanocubes have exhibited higher photocatalytic activity and stability than Cu2WSe4 nanosheets. The photocatalytic HER rates of Cu2WS4 and Cu2WSe4 have been determined as 1260 mu mol g(-1) h(-1) and 861 mu mol g(-1) h(-1), respectively. Photocatalytic HER activities were figured out in the order of Cu2WS4 > Cu2WSe4 which could be attributed to differences between proton reduction potential and the conduction band energy levels

Hydrogen Evolution Catalyzed by Cu₂WS₄ at Liquid–Liquid Interfaces

The present study reports, for the first time, both a facile synthesis for ternary Cu₂WS₄ nanocubes, which were synthesized by a simple and low-cost hot-injection method, and the hydrogen evolution reaction at a biomembrane-like polarized water/1,2-dichloroethane interface catalyzed by Cu₂WS₄ nanocubes. The rate of hydrogen evolution reaction is increased by about 1000 times by using Cu₂WS₄ nanocubes when compared to an uncatalyzed reaction

Scheelite-type BaMoO4 and BaWO4 based dye sensitized photocatalytic hydrogen evolution by water splitting

WOS:000813011000005Nowadays, the development of cost-effective and stable catalyst has greatly drawn attention for electrocatalytic and photocatalytic hydrogen evolution reactions. Herein, photocatalytic hydrogen evolution has been investigated by using BaMoO4 and BaWO4 catalysts in the presence of triethanolamine and eosin-Y as a sacrificial agent and visible-light-sensitizer, respectively. These refractory metal-based oxides prepared by solid phase synthesis procedure have been characterized by structural, morphological, optical and electrochemical techniques, which are obtained with high crystallinity and adequate stoichiometric ratios. While the hydrogen evolution rate of BaMoO4 is higher than BaWO4 in the first hours of photocatalytic reaction, BaWO4 displays more stable activity for hydrogen evolution, which is reached 3.37 mmolg−1 after the 8 h of photocatalytic reaction. The proposed mechanism of dye-sensitized photocatalytic hydrogen evolution is explained by data obtained from optical and electrochemical propertie

Synthesis of novel tetrazine based D-π-A organic dyes for photoelectrochemical and photocatalytic hydrogen evolution

WOS:000512481000008Two novel donor-pi-acceptor (D-pi-A) dyes, called as MK-2 and MK-8, are synthesized. Their structural, optical and electrochemical properties are investigated by NMR, absorption/photoluminescence spectroscopies and cyclic voltammetry techniques, respectively. Photocatalytic and photoelectrochemical hydrogen evolution properties of these D-pi-A dyes are explored by using triethanolamine (TEOA) as a sacrificial electron donor under anaerobic conditions and visible light irradiation with or without co-catalysts (Cu2WS4 and Pt) for the first time. Photoelectrochemical and photocatalytic hydrogen evolution reaction (HER) activities of these dyes are studied by using TiO2 coated FTO electrodes and powdered TiO2 (Degussa P25), respectively. Photoelectrochemical response of MK-2/TiO2 and MK-8/TiO2 are figured out in the order of 180 mu A cm(-1) and 80 A cm(-1). The photocatalytic hydrogen evolution amounts of MK-2/TiO2, MK-2/TiO2/Cu2WS4, MK-2/TiO2/Pt, MK-8/TiO2, MK-8/TiO2/Cu2WS4 and MK-8/TiO2/Pt are turned out to be 565, 920, 1828, 374, 522 and 1260 mu molg(-1) h(-1), respectively. Dye/TiO2 photocatalysts are displayed good stability in the both photochemical HER experiments. The alteration in the HER activities of MK-2 and MK-8 is explained by molecule structures of dyes. The proposed mechanism of photocatalytic hydrogen evolution is clarified by using electrochemical band levels of each constituent.This article has been funded by Turkish Academy of Sciences via a TUBA-GEBIP fellowship, UNESCO-Loreal and The Scientific and Technological Research Council of Turkey (TUBITAK) (215M309). This study is prepared by part of Emre Asian's Ph.D thesis

Photoinduced biphasic hydrogen evolution: decamethylosmocene as a light-driven electron donor

Excitation of the weak electron donor decamethylosmocene on illumination with white light produces an excited‐state species capable of reducing organically solubilized protons under biphasic conditions. Insight into the mechanism and kinetics of light‐driven biphasic hydrogen evolution are obtained by analysis with gas chromatography, cyclic voltammetry, and UV/Vis and 1H NMR spectroscopy. Formation of decamethylosmocenium hydride, which occurs prior to hydrogen evolution, is a rapid step relative to hydrogen release and takes place independently of light activation. Remarkably, hydride formation occurs with greater efficiency (ca. 90 % conversion) under biphasic conditions than when the reaction is carried out in an acidified single organic phase (ca. 20 % conversion). Cyclic voltammetry studies reveal that decamethylosmocene has a higher proton affinity than either decamethylferrocene or osmoceneACCEPTEDpeer-reviewe

Facile preparation of amorphous NiWSex and CoWSex nanoparticles for the electrocatalytic hydrogen evolution reaction in alkaline condition

WOS:000514251800057The development of catalysts as an alternative to platinum group metals (PGMs) has great importance to improve the efficiency of hydrogen evolution reaction (HER). Herein, the novel amorphous ternary refractory metal selenides (MWSex; M = Co and Ni), which were synthesized by hot-injection approach, were firstly investigated on the electrocatalytic HER in alkaline media. Optical, electrochemical and magnetic properties of the electrocatalysts were explored, as well as the chemical structures and morphologies. These results clearly show that the obtained materials are having the amorphous crystal structure and are shaped as spherical and rod-like structures. Moreover, the addition of Ni and Co metals into the WSex structure were raised the catalytic activity of HER comparing to that of only WSex. This work paves the way for the exploration of copper-based amorphous selenides as electrocatalysts for the hydrogen evolution in order to replace noble metal Pt. (C) 2019 Elsevier B.V. All rights reserved.The authors would like to thank TUBITAK (The Scientific and Technological Research 'Council of Turkey) (Grant number: 215M309), Karamanoglu Mehmetbey University, Scientific Research Foundation (Grand Number: 32-M-16) and Turkish Academy of Sciences via a TUBA-GEBIP fellowship for supporting this work

Photoinduced biphasic hydrogen evolution: decamethylosmocene as a light-driven electron donor

Excitation of the weak electron donor decamethylosmocene on illumination with white light produces an excited‐state species capable of reducing organically solubilized protons under biphasic conditions. Insight into the mechanism and kinetics of light‐driven biphasic hydrogen evolution are obtained by analysis with gas chromatography, cyclic voltammetry, and UV/Vis and 1H NMR spectroscopy. Formation of decamethylosmocenium hydride, which occurs prior to hydrogen evolution, is a rapid step relative to hydrogen release and takes place independently of light activation. Remarkably, hydride formation occurs with greater efficiency (ca. 90 % conversion) under biphasic conditions than when the reaction is carried out in an acidified single organic phase (ca. 20 % conversion). Cyclic voltammetry studies reveal that decamethylosmocene has a higher proton affinity than either decamethylferrocene or osmocen