Surface coordination chemistry of noble-metal electrocatalysts: Oxidative addition and reductive elimination of iodide at iridium, platinum and gold in aqueous solutions

Rodrı́guez, Julio; Harris, John E.; Bothwell, Michael E.; Mebrahtu, Thomas; Soriaga, Manuel P.

doi:10.1016/s0020-1693(00)86022-3

Cited by 22 publications

(18 citation statements)

References 22 publications

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“…Also, the iodine-coated platinum electrode does not need to regenerate before each measurement where scanned potential window should between -0.2 and 1.0 V, which indicates to reliability of using the electrode for daily routine analysis. The effect of pH on the iodine coating on platinum electrode has been reported elsewhere [35] where it has been found that iodine coating is unstable upon cyclization in basic solution [36] . This fact limits usage of iodine-coated electrode to acidic solutions only.…”

Section: Electrochemical Oxidation Of Paracetamol and Methods Validationmentioning

confidence: 81%

Voltammetric Determination of Paracetamol in Pharmaceutical Formulations at Iodine-Coated Polycrystalline Platinum Electrode

Amayreh

Hourani²,

Hourani

2021

MOCA

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In this work the modified iodine-coated polycrystalline platinum electrode was used to develope a voltammetric sensor for paracetamol determination in pharmaceutical formulations. The optimized experimental parameters for the determination of paracetamol were using 0.5 M H2SO4 as a supporting electrolyte with a scan rate of 50 mV/s. The anodic peak related to paracetamol oxidation was centered at about +0.60 V. The extended calibration graph was constructed between 1 ppm and 500 ppm. The anodic current showed excellent linearity with R2 = 0.9985. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.046 and 0.139 ppm, respectively, which attests to the sensitivity of the method. The investigation for the effect of potential interferences from the content of tablet matrices indicated a specific selectivity toward paracetamol and the absence of any electrochemical response toward these components. The developed method was successfully applied to analysis paracetamol in three brands of pharmaceutical formulations and the obtained results were in good agreement with the labeled values, besides that, the statistical tests indicated no significant difference at p = 0.05 with a 95 % confidence level.

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Section: Electrochemical Oxidation Of Paracetamol and Methods Validationmentioning

confidence: 81%

Voltammetric Determination of Paracetamol in Pharmaceutical Formulations at Iodine-Coated Polycrystalline Platinum Electrode

Amayreh

Hourani²,

Hourani

2021

MOCA

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“…The effect of pH on the iodine coating on platinum electrode has been reported elsewhere 33 where it was found that iodine coating is unstable upon cyclization in basic solutions. 34 This fact limits the use of an iodine-coated electrode to acidic solutions only. The effect of the pH in the acidic range was investigated by following the effect of pH change on the peak current for gallic acid oxidation.…”

Section: Resultsmentioning

confidence: 99%

Voltammetric Determination of Gallic Acid and its Content in Tea Samples Using Modified Iodine-Coated Platinum Electrode

2021

TJNPR

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While platinum electrode shows high reactivity towards adsorption processes, iodine-coated platinum electrode offers remarkable inertness toward these processes. Therefore, iodine-coated platinum electrodes have become very significant in voltammetric applications. This study reports the use of the modified iodine-coated polycrystalline platinum electrode as a voltammetric sensor for gallic acid determination in tea samples. The optimized experimental parameters for determining gallic acid used 0.5M H2SO4 as a supporting electrolyte with a scan rate of 50 mV/s. The anodic peak related to gallic acid oxidation was centered at approximately 0.60V. The extended detected linear range for the developed method was between 0.025 and 2.0 mM. The anodic current showed excellent linearity with R 2 =0.9975. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.022mM and 0.0669 mM, respectively, which confirmed the method's sensitivity. The investigation for the effect of potential interferences from tea components indicated a specific selectivity toward gallic acid with only slight interference due to the presence of ascorbic acid and the absence of any electrochemical response toward glucose, caffeine, Ni 2+ , K + , Na + , and Zn 2+ . The proposed method was successfully applied in the analysis of gallic acid in tea samples. The recovery values (90.0 -103.25%) obtained in this study support the use of the developed method to analyze gallic acid in tea samples.

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“…3,5,15 Prior to first use, it was cleaned by multiple cycles of Ar + -ion bombardment, thermal oxidation in 10 −6 Torr O 2 , and high-temperature annealing (1020 K). Before each measurement, the crystallinity of the (111)-surface was verified by low-energy electron diffraction (LEED), and its surface cleanliness was established by AES.…”

Section: Methodsmentioning

confidence: 99%

“…Surface coverage and adsorbed-molecule cross section data from TLE and HREELS measurements revealed non-random concentration-dependent adsorbate orientations similar to the oxidative chemisorption of hydroquinone: flat at low concentrations and edgewise at elevated concentrations. The DFT results suggested that, for the flat structure, surface coordination is via the two double bonds of the quinone ring as in [Pd(2,3,5,. For the edge-vertical orientation, a structure analogous to an o-phenylene compound is generated in which C-H bonds at the 5 and 6 ring positions are activated and then metalated.…”

mentioning

confidence: 99%

C–H activation and metalation at electrode surfaces: 2,3-dimethyl-1,4-dihydroxybenzene on Pd(pc) and Pd(111) studied by TLE, HREELS and DFT

Javier

Cruz

et al. 2014

Dalton Trans.

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Previous studies, based on thin-layer electrochemistry (TLE), in situ scanning tunneling microscopy (EC-STM), high-resolution electron energy loss spectroscopy (HREELS) and density functional theory (DFT) computations, on the chemical adsorption of hydroquinone from aqueous solutions onto atomically smooth Pd (and Pt) electrode surfaces indicated two modes of attachment that depended upon the solution concentration. At low activities, the diphenol was oxidatively chemisorbed as benzoquinone in a flat orientation, suggestive of a Pd(2,3,5,6-η-C 6 H 4 O 2 ) surface complex; at higher concentrations, vertical chemisorption was effected via two C-H bond activations (or metalations) at the 2 and 3 ring positions, evocative of an o-phenylene organopalladium compound. We have extended the work to 2,3-dimethyl-1,4-dihydroxybenzene on Pd( pc) and Pd(111) electrodes to probe the effect of two methyl substituents on only one side of the diphenol ring. Surface coverage and adsorbed-molecule cross section data from TLE and HREELS measurements revealed non-random concentration-dependent adsorbate orientations similar to the oxidative chemisorption of hydroquinone: flat at low concentrations and edgewise at elevated concentrations. The DFT results suggested that, for the flat structure, surface coordination is via the two double bonds of the quinone ring as in [Pd(2,3,5,. For the edge-vertical orientation, a structure analogous to an o-phenylene compound is generated in which C-H bonds at the 5 and 6 ring positions are activated and then metalated. DFT-simulated HREELS spectra helped identify the observed peaks that distinguish the surface-coordinated quinone from the surface-metalated diphenol.

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Surface coordination chemistry of noble-metal electrocatalysts: Oxidative addition and reductive elimination of iodide at iridium, platinum and gold in aqueous solutions

Cited by 22 publications

References 22 publications

Voltammetric Determination of Paracetamol in Pharmaceutical Formulations at Iodine-Coated Polycrystalline Platinum Electrode

Voltammetric Determination of Paracetamol in Pharmaceutical Formulations at Iodine-Coated Polycrystalline Platinum Electrode

Voltammetric Determination of Gallic Acid and its Content in Tea Samples Using Modified Iodine-Coated Platinum Electrode

C–H activation and metalation at electrode surfaces: 2,3-dimethyl-1,4-dihydroxybenzene on Pd(pc) and Pd(111) studied by TLE, HREELS and DFT

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