Imren Hatay Patir

An electrochemical biosensor based on human serum albumin/graphene oxide/3-aminopropyltriethoxysilane modified ITO electrode for the enantioselective discrimination of D- and L-tryptophan.

A new electrochemical biosensor based on the human serum albumin/graphene oxide/3-aminopropyl-triethoxysilane modified indium tin oxide electrode (ITO/APTES/GO/HSA) has been developed for the discrimination of tryptophan (Trp) enantiomers.The electrode has been characterized by scanning electron microscopy (SEM) and electrochemical techniques. The electrochemical behaviors of the enantiomeric pairs (D- and L-Trp) at the ITO/APTES/GO/HSA electrode have been investigated by cyclic voltammetry in the concentration range of 0.10-1.0 mM. A clear separation between the oxidation peak potentials of D- and L-Trp, at 0.86 and 1.26 V, respectively, has suggested that the ITO/APTES/GO/HSA electrode can be used as an electrochemical biosensor for the discrimination of Trp enantiomers. In order to find the percentage of an enantiomeric form of tryptophan in a mixture, the ITO/APTES/GO/HSA electrode is used for the simultaneous detection of D- and L-Trp which showed that the percentage of one enantiomeric form can be easily measured in the presence of the other.

Biphasic water splitting by osmocene

The photochemical reactivity of osmocene in a biphasic water-organic solvent system has been investigated to probe its water splitting properties. The photoreduction of aqueous protons to hydrogen under anaerobic conditions induced by osmocene dissolved in 1,2-dichloroethane and the subsequent water splitting by the osmocenium metal-metal dimer formed during H2 production were studied by electrochemical methods, UV-visible spectrometry, gas chromatography, and nuclear magnetic resonance spectroscopy. Density functional theory computations were used to validate the reaction pathways.

Highly Active Cobalt Sulfide/Carbon Nanotube Catalyst for Hydrogen Evolution at Soft Interfaces.

Hydrogen evolution at polarized liquid-liquid interfaces [water/1,2-dichloroethane (DCE)] by the electron donor decamethylferrocene (DMFc) is catalyzed efficiently by the fabricated cobalt sulfide (CoS) nanoparticles and nanocomposites of CoS nanoparticles formed on multi-walled carbon nanotubes (CoS/CNT). The suspended CoS/CNT nanocomposite catalysts at the interface show a higher catalytic activity for the hydrogen evolution reaction (HER) than the CoS nanoparticles due to the high dispersity and conductivity of the CNT materials, which can serve as the main charge transport pathways for the injection of electrons to attain the catalytic sites of the nanoparticles. The reaction rate increased more than 1000-fold and 300-fold by using CoS/CNT and CoS catalysts, respectively, when compared to a non-catalyzed reaction.

Cu Nanoparticles Electrodeposited at Liquid–Liquid Interfaces: A Highly Efficient Catalyst for the Hydrogen Evolution Reaction

The electrochemical deposition of Cu nanoparticles with an average diameter of approximately 25-35 nm has been reported at liquid-liquid interfaces by using the organic-phase electron-donor decamethylferrocene (DMFc). The electrodeposited Cu nanoparticles display excellent catalytic activity for the hydrogen evolution reaction (HER); this is the first reported catalytic effect of Cu nanoparticles at liquid-liquid interfaces.

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 (1)H 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 osmocene.

Dye-Sensitized Cu2XSnS4 (X=Zn, Ni, Fe, Co, and Mn) Nanofibers for Efficient Photocatalytic Hydrogen Evolution

The photocatalytic hydrogen evolution activities of low-cost and noble-metal-free Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofiber catalysts have been investigated using triethanolamine as an electron donor and eosin Y as a photosensitizer under visible-light irradiation. The rates of hydrogen evolution by Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofibers have been compared with each other and with that of the noble metal Pt. The hydrogen evolution rates for the nanofibers change in the order Cu2 NiSnS4 >Cu2 FeSnS4 >Cu2 CoSnS4 >Cu2 ZnSnS4 >Cu2 MnSnS4 (2028, 1870, 1926, 1420, and 389 μmol g(-1) h(-1) , respectively). The differences between the hydrogen evolution rates of the nanofibers could be attributed to their energy levels. Moreover, Cu2 NiSnS4, Cu2 FeSnS4 , and Cu2 CoSnS4 nanofibers show higher and more stable photocatalytic hydrogen production rates than that of the noble metal Pt under long-term irradiation with visible light.

Catalytic Hydrogen Evolution by Tungsten Disulfide at Liquid–Liquid Interfaces

WS2, which is composed of cheap and earth‐abundant elements, catalyzes the hydrogen‐evolution reaction efficiently using the organic electron‐donor decamethylferrocene. This catalytic activity has been investigated at liquid–liquid interfaces (water–1,2‐dichloroethane) by voltammetry and biphasic reactions observed by UV/Vis spectroscopy and GC.

Enhanced Hydrogen Evolution Catalysis Based on Cu Nanoparticles Deposited on Carbon Nanotubes at the Liquid/Liquid Interface

Copper nanoparticles were electrodeposited in situ on a conductive multi‐walled carbon nanotubes (MWCNT) support at a free‐standing water/1,2‐dichloroethane interface. The Cu/MWCNT nanocomposites act as highly active hydrogen evolution catalysts at the interface in the presence of lipophilic decamethylferrocene as the reducing agent.

Photocatalytic hydrogen evolution based on Cu2ZnSnS4, Cu2ZnSnSe4 and Cu2ZnSnSe4−xSx nanofibers

New photocatalytic systems for hydrogen evolution from water have been reported by using low cost and environmentally-friendly Cu2ZnSnS4, Cu2ZnSnSe4, and Cu2ZnSnSe4−xSx nanofiber catalysts in the presence of eosin Y as a photosensitizer and a sacrificial reducing agent triethanolamine under visible light irradiation. The rate of hydrogen evolution with Cu2ZnSnS4 is greater than those with Cu2ZnSnSe4 and Cu2ZnSnSe4−xSx, producing hydrogen at 1428 μmol g−1 h−1, 833 μmol g−1 h−1 and 739 μmol g−1 h−1, respectively.

Photocatalytic Hydrogen Evolution by Oleic Acid‐Capped CdS, CdSe, and CdS0.75Se0.25 Alloy Nanocrystals

Photocatalytic generation of hydrogen by using oleic acid-capped CdS, CdSe, and CdS(0.75)Se(0.25) alloy nanocrystals (quantum dots) has been investigated under visible-light irradiation by employing Na(2)S and Na(2)SO(3) as hole scavengers. Highly photostable CdS(0.75)Se(0.25) alloy nanocrystals gave the highest hydrogen evolution rate (1466 μmol h(-1) g(-1)), which was about three times higher than that of CdS and seven times higher than that of CdSe.