UV–visible spectroscopic and electrochemical study of the complex formation between Fe(II) and 5-amino-1,10-phenantroline (5-Aphen) in aqueous solution

Lozano-Camargo, María Luisa; Rojas-Hernándéz, Alberto; Gómez-Hernández, Martín; Pacheco-Hernández, Ma de Lourdes; Galicia, Laura; Ramı́rez-Silva, Maria Teresa

doi:10.1016/j.talanta.2007.01.065

Cited by 10 publications

(2 citation statements)

References 11 publications

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“…The subsurface bond of the metal center resulted in an effective catalysis of ORR by the porphyrin with virtually no hydrogen peroxide production. , Based on the sixfold coordination of iron, likely present in some pyrolyzed Fe/C/N catalysts, a subsurface coordination of the metal center (“interaction with an adjacent graphene layer”) was also suggested for those materials . The hypothetical subsurface bonding of the metal center in the nonprecious-metal-based heat-treated catalysts seems to agree with their higher stability in strongly acidic media compared to related macrocyclic complexes of transition metals. − Viewed from the above perspective, studies of the immediate environment of transition metal centers in these catalysts, including possible subsurface coordination bonds, may help understand better the respective mechanisms of ORR and possibly further improve the catalytic activity of the pyrolyzed nonprecious ORR catalysts.…”

Section: Discussionmentioning

confidence: 77%

RRDE and Voltammetric Study of ORR on Pyrolyzed Fe/Polyaniline Catalyst. On the Origins of Variable Tafel Slopes

2011

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Catalytic activity of heat-treated iron and polyaniline-based oxygen reduction catalysts was studied in aqueous acidic media using the rotating ring disk (RRDE) technique and linear potential scan voltammetry employing stationary electrodes. The stationary voltammograms of the catalyst exhibit the presence of a reversible surface redÀox reaction at 0.647 V vs RHE. It is shown that molecular oxygen reversibly adsorbs on the catalyst surface at potentials more positive than the formal potential of the surface redÀox couple and that the adsorption occurs through either the oxidized form of this couple or an atom in its close proximity. The Tafel plots for oxygen reduction reaction (ORR) exhibit variable slopes ranging from 60 mV dec À1 at the lowest overpotentials to more than 240 mV dec À1 at high overpotentials. The kinetic data obtained from the RRDE experiments for various catalyst loadings and from the linear potential scan voltammetry of adsorbed oxygen demonstrate that the high Tafel slopes originate from intrinsic features of the reduction mechanism rather than incomplete catalyst utilization. It is postulated that the surface redÀox couple is Fe III /Fe II and that it takes an active part in ORR in the whole range of overpotentials. The proposed ORR mechanism involves a simple mediation by the Fe III /Fe II couple at low overpotentials and a concerted process of charge transfer and oxygenÀoxygen bond splitting at high overpotentials.

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Section: Discussionmentioning

confidence: 77%

RRDE and Voltammetric Study of ORR on Pyrolyzed Fe/Polyaniline Catalyst. On the Origins of Variable Tafel Slopes

2011

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“…The following components react with Fe(II): 2,2′-bipirydyl forming a red complex with the maximum absorption at 520 nm (Whitehead and Malik 1975) and 1,10-phenanthroline, also forming a red complex with the maximum absorption of approx. 510 nm (Harvey et al 1955;Lozano-Camargo et al 2007). In turn, thiocyanate ions and Fe(III) form a red complex with the maximum absorption at 475-485 nm (Tarafder and Thakur 2005), while 1,10-phenanthroline forms a yellow complex with the maximum absorption of 396 nm (Harvey et al 1955).…”

Section: Introductionmentioning

confidence: 99%

Determination of Iron Species in Samples of Iron-Fortified Food

et al. 2014

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The paper presents the determination of iron forms in food products. The procedure of sample extraction was developed and optimized, preserving the content of particular forms of iron. The colorimetric method using 2,2′-bipirydyl (measurements at 520 nm) was applied in Fe(II) determinations, while in Fe(III) determinations, the colorimetric method with potassium thiocyanate (measurements at 470 nm) was applied. The total content of iron was determined by the technique of atomic absorption spectrometry, which allowed for the determination of iron content in organic and inorganic complex compounds. Detection limits of 1 mg kg −1 were obtained for all determined iron forms, with the precision ranging between 0.7 % and 1.5 % for 10 mg kg −1 concentration. The optimized analytical procedure was applied in the determinations of iron forms in iron-fortified food products.

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Biofuel Cell Based on Anode and Cathode Modified by Glucose Oxidase

et al. 2013

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A single compartment biofuel cell (BFC) based on an anode and a cathode powered by the same fuel glucose is reported. Glucose oxidase (GOx) from Aspergillus niger was applied as a glucose consuming biocatalyst for both anode and cathode of the BFC. The 5‐amino‐1,10‐phenanthroline modified graphite rod electrode (GRE) with cross‐linked GOx was used as the bioanode, and the GRE with co‐immobilised horseradish peroxidase and GOx was exploited as the biocathode of the BFC. The open‐circuit voltage of the designed BFC exceeded 450 mV and a maximal power density of 3.5 µW/cm2 was registered at a cell voltage of 300 mV.

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UV–visible spectroscopic and electrochemical study of the complex formation between Fe(II) and 5-amino-1,10-phenantroline (5-Aphen) in aqueous solution

Cited by 10 publications

References 11 publications

RRDE and Voltammetric Study of ORR on Pyrolyzed Fe/Polyaniline Catalyst. On the Origins of Variable Tafel Slopes

RRDE and Voltammetric Study of ORR on Pyrolyzed Fe/Polyaniline Catalyst. On the Origins of Variable Tafel Slopes

Determination of Iron Species in Samples of Iron-Fortified Food

Biofuel Cell Based on Anode and Cathode Modified by Glucose Oxidase

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