Electrochemical studies of heated treated NiCrMoFeCoAl and NiCrMoFeCoAl‐30%Cr 3 C 2 HVOF coatings on T22 boiler steel

Iron- and nitrogen-doped carbon (Fe-N-C) materials are leading candidates to replace platinum in fuel cells, but their active site structures are poorly understood. A leading postulate is that iron active sites in this class of materials exist in an Fe-N4 pyridinic ligation environment. Yet, molecular Fe-based catalysts for the oxygen reduction reaction (ORR) generally feature pyrrolic coordination and pyridinic Fe-N4 catalysts are, to the best of our knowledge, non-existent. We report the synthesis and characterization of a molecular pyridinic hexaazacyclophane macrocycle, (phen2N2)Fe, and compare its spectroscopic, electrochemical, and catalytic properties for oxygen reduction to a prototypical Fe-N-C material, as well as iron phthalocyanine, (Pc)Fe, and iron octaethylporphyrin, (OEP)Fe, prototypical pyrrolic iron macrocycles. N 1s XPS signatures for coordinated N atoms in (phen2N2)Fe are positively shifted relative to (Pc)Fe and (OEP)Fe, and overlay with those of Fe-N-C. Likewise, spectroscopic XAS signatures of (phen2N2)Fe are distinct from those of both (Pc)Fe and (OEP)Fe, and are remarkably similar to those of Fe-N-C with compressed Fe–N bond lengths of 1.97 Å in (phen2N2)Fe that are close to the average 1.94 Å length in Fe-N-C. Electrochemical studies establish that both (Pc)Fe and (phen2N2)Fe have relatively high Fe(III/II) potentials at ~0.6 V, ~300 mV positive of (OEP)Fe. The ORR onset potential is found to directly correlate with the Fe(III/II) potential leading to a ~300 mV positive shift in the onset of ORR for (Pc)Fe and (phen2N2)Fe relative to (OEP)Fe. Consequently, the ORR onset for (phen2N2)Fe and (Pc)Fe is within 150 mV of Fe-N-C. Unlike (OEP)Fe and (Pc)Fe, (phen2N2)Fe displays excellent selectivity for 4-electron ORR with <4% maximum H2O2 production, comparable to Fe-N-C materials. The aggregate spectroscopic and electrochemical data establish (phen2N2)Fe as a pyridinic iron macrocycle that effectively models Fe-N-C active sites, thereby providing a rich molecular platform for understanding this important class of catalytic materials.

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SURFACE ENHANCEMENT AND IMPROVED MECHANICAL PROPERTIES OF SA-210 GR. A1 BOILER STEEL BY FRICTION STIR PROCESSING

i-manager s Journal on Material Science ◽

10.26634/jms.7.2.15941 ◽

2019 ◽

Vol 7 (2) ◽

pp. 49

Author(s):

SINGH SUPREET ◽

KAUR MANPREET ◽

KUMAR MANOJ ◽

SINGH HARPRABHJOT ◽

SINGH NAVNEETINDER ◽

...

Keyword(s):

Mechanical Properties ◽

Friction Stir Processing ◽

Boiler Steel ◽

Surface Enhancement ◽

Friction Stir

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Inhibition Effects of Some Organic Compounds on Zinc Corrosion in 3.5% NaCl

Revista de Chimie ◽

10.37358/rc.08.5.1824 ◽

2008 ◽

Vol 59 (5) ◽

Cited By ~ 1

Author(s):

Viorel Branzoi ◽

Alina Pruna ◽

Florina Branzoi

Keyword(s):

Organic Compounds ◽

Electrochemical Impedance ◽

Corrosion Process ◽

Diffusion Control ◽

Cathodic Reaction ◽

Zinc Electrode ◽

Electrochemical Studies ◽

Nacl Solution ◽

Sodium Dodecylsulphate ◽

Zinc Corrosion

The inhibition of zinc corrosion in 3.5% NaCl solution by some organic compounds (sodium dodecylsulphate (SDS), sodium dodecylbenzosulphonate (SDBS) and sodium 1,4-bis(2-etylhexyl) sulphosuccinate (AOT)) was investigated. The inhibition efficiencies were determined by polarization measurements of the zinc electrode in the solution. Electrochemical impedance spectroscopy (EIS) was also used for electrochemical studies of zinc electrode in this medium. The results showed that the used surfactants inhibit the cathodic reaction of hydrogen evolution and at low anodic overvoltage the corrosion process is under activation control, while at high anodic overvoltage the process is under diffusion control.

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QCM and Electrochemical Studies of Li Intercalation in V6O13

10.21236/ada228849 ◽

1990 ◽

Author(s):

Heai-Ku Park ◽

Kathryn Podolske ◽

Zafar Munshi ◽

W. H. Smyrl ◽

B. B. Owens

Keyword(s):

Electrochemical Studies

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Naphthoquinone-based hydrazone hybrids: synthesis and potent activity against cancer cell lines

Medicinal Chemistry ◽

10.2174/1573406416666200817164308 ◽

2020 ◽

Vol 16 ◽

Author(s):

Délis Galvão Guimarães ◽

Arlan de Assis Gonsalves ◽

Larissa Araújo Rolim ◽

Edigênia Cavalcante Araújo ◽

Victória Laysna dos Anjos Santos ◽

...

Keyword(s):

Anticancer Activity ◽

Cell Lines ◽

Cancer Cell ◽

Biological Activities ◽

Supporting Electrolyte ◽

Cancer Cell Lines ◽

Molecular Structures ◽

Cytotoxic Activities ◽

Electrochemical Studies ◽

Ic50 Values

Background: Natural naphthoquinones have shown diversified biological activities including antibacterial, antifungal, antimalarial, and cytotoxic activities. However, they are also compounds with acute cytotoxicity, immunotoxicity, carcinogenesis, and cardio- and hepatotoxicity, then the modification at their redox center is an interesting strategy to overcome such harmful activity. Objective: In this study, four novel semisynthetic hydrazones, derived from the isomers α- and β-lapachones (α and β, respectively) and coupled with the drugs hydralazine (HDZ) and isoniazid (ACIL), were prepared, evaluated by electrochemical methods and assayed for anticancer activity. Method: The semisynthetic hydrazones were obtained and had their molecular structures established by NMR, IR, and MS. Anticancer activity was evaluated by cell viability determined by reduction of 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (MTT). The electrochemical studies, mainly cyclic voltammetry, were performed, in aprotic and protic media. Result: The study showed that the compounds 2, 3, and 4 were active against at least one of the cancer cell lines evaluated, being compounds 3 and 4 the most cytotoxic. Toward HL-60 cells, compound 3 was 20x more active than β-lapachone, and 3x more cytotoxic than doxorubicin. Furthermore, 3 showed an SI value of 39.62 for HL-60 cells. Compound 4 was active against all cancer cells tested, with IC50 values in the range 2.90–12.40 μM. Electrochemical studies revealed a profile typical of self-protonation and reductive cleavage, dependent on the supporting electrolyte. Conclusion: These results therefore indicate that compounds 3 and 4 are strong candidates as prototypes of new antineoplastic drugs.

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Magnetic and electrochemical studies on electrodeposited Ni-Fe alloys

Magnetohydrodynamics ◽

10.22364/mhd.42.4.3 ◽

2006 ◽

Vol 42 (4) ◽

pp. 371-378 ◽

Cited By ~ 4

Keyword(s):

Electrochemical Studies ◽

Fe Alloys

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Papaver somniferum as an efficient corrosion inhibitor for iron alloy in acidic condition: DFT, MC simulation, LCMS and Electrochemical studies

Journal of Molecular Structure ◽

10.1016/j.molstruc.2021.130822 ◽

2021 ◽

pp. 130822

Author(s):

Rajesh Haldhar ◽

Seong-Cheol Kim ◽

Dwarika Prasad ◽

M.A. Bedair ◽

Indra Bahadur ◽

...

Keyword(s):

Corrosion Inhibitor ◽

Iron Alloy ◽

Papaver Somniferum ◽

Acidic Condition ◽

Electrochemical Studies ◽

Mc Simulation

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Sulfanyl Porphyrazines with Morpholinylethyl Periphery—Synthesis, Electrochemistry, and Photocatalytic Studies after Deposition on Titanium(IV) Oxide P25 Nanoparticles

Molecules ◽

10.3390/molecules26082280 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2280

Author(s):

Tomasz Koczorowski ◽

Wojciech Szczolko ◽

Anna Teubert ◽

Tomasz Goslinski

Keyword(s):

Diclofenac Sodium ◽

2D Nmr ◽

Oxide Nanoparticles ◽

Electrochemical Studies ◽

Macrocyclic Compounds ◽

Active Pharmaceutical Ingredients ◽

Pharmaceutical Ingredients ◽

Vis Spectroscopy ◽

Singlet Oxygen Quencher ◽

Nmr Techniques

The syntheses, spectral UV–Vis, NMR, and electrochemical as well as photocatalytic properties of novel magnesium(II) and zinc(II) symmetrical sulfanyl porphyrazines with 2-(morpholin-4-yl)ethylsulfanyl peripheral substituents are presented. Both porphyrazine derivatives were synthesized in cyclotetramerization reactions and subsequently embedded on the surface of commercially available P25 titanium(IV) oxide nanoparticles. The obtained macrocyclic compounds were broadly characterized by ESI MS spectrometry, 1D and 2D NMR techniques, UV–Vis spectroscopy, and subjected to electrochemical studies. Both hybrid materials, consisting of porphyrazine derivatives embedded on the titanium(IV) oxide nanoparticles’ surface, were characterized in terms of particle size and distribution. Next, they were subjected to photocatalytic studies with 1,3-diphenylisobenzofuran, a known singlet oxygen quencher. The applicability of the obtained hybrid material consisting of titanium(IV) oxide P25 nanoparticles and magnesium(II) porphyrazine derivative was assessed in photocatalytic studies with selected active pharmaceutical ingredients, such as diclofenac sodium salt and ibuprofen.

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