THE ADSORPTION OF BiIII/Pt NANOCOMPOSITES AT PLATINUM ELECTRODE WITH HIGHLY ENHANCED ELECTROCATALYSIS TOWARD GLUCOSE

2014 ◽  
Vol 21 (03) ◽  
pp. 1450042 ◽  
Author(s):  
ZHUOYUAN YANG ◽  
YUQING MIAO ◽  
TIANRUI WANG ◽  
MINGSHU XIAO ◽  
XIAOCAI LIANG ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Active Site ◽  
Active Sites ◽  
Platinum Electrode ◽  
High Sensitivity ◽  
Glucose Detection ◽  
Pt Electrode ◽  
Positive Potential ◽  
Simple Method ◽  
Oxidation Of Glucose

In this paper, we first fabricated a nanoPt modified platinum electrode. Then through a simple method, the electrode surface was introduced with a submonolayer of bismuth that acted as an effective promoter. Cyclic voltammetry and other characterizations were employed. The obtained Bi III / nanoPt / Pt electrode exhibited two greatly increased oxidation peaks at negative and positive potential areas, respectively. The signals were far larger than that of platinum electrode because of the large true surface area of nanoparticles and the catalysis of bismuth adsorbed on platinum. In the presence of bismuth, the platinum active sites could combine with more OH - from bismuth hydroxyl to form a new active site for the oxidation of glucose. The prepared Bi III / nanoPt / Pt electrode given high sensitivity and excellent linearship to glucose detection and showed the potential application in the areas of electrocatalysis or electroanalysis.

scholarly journals Solvothermal synthesis of Fe3O4 nanospheres for high-performance electrochemical non-enzymatic glucose sensor

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiasheng Xu ◽  
Yuting Sun ◽  
Jie Zhang
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Glucose Sensor ◽  
Limit Of Detection ◽  
Glucose Monitoring ◽  
High Sensitivity ◽  
Blood Glucose Monitoring ◽  
Glucose Detection ◽  
Uniform Size ◽  
Long Term Stability

Abstract Ferroferric oxide (Fe3O4) nanospheres have been synthesized via a facile solvothermal procedure to serve as an electrode material for high performance non-enzymatic glucose sensor. The as-synthesized Fe3O4 nanospheres with a uniform size from 16 to 18 nm, which can increase the reaction contact area and the active sites in the process of glucose detection. Benefiting from the particular nanoscale structure, the Fe3O4 nanospheres obviously enhanced the activity of electrocatalytic oxidation towards glucose. When the Fe3O4 nanospheres material was used for non-enzymatic glucose sensor, several electrochemical properties including the high sensitivity 6560 μA mM−1 cm−2 (0.1–1.1 mM), limit of detection 33 μM (S/N = 3) and good long-term stability were well demonstrated. Furthermore, Fe3O4 nanospheres electrode confirmed the excellent performance of selectivity in glucose detection with the interfering substances existed such as urea, citric acid, ascorbic acid, and NaCl. Due to the excellent electrocatalytic activity in alkaline solution, the Fe3O4 nanospheres material can be considered as a promising candidate in blood glucose monitoring.

scholarly journals Intramolecular coupling of active sites in the pyruvate dehydrogenase multienzyme complexes from bacterial and mammalian sources

1981 ◽  
Vol 195 (3) ◽  
pp. 715-721 ◽  
Author(s):  
C J Stanley ◽  
L C Packman ◽  
M J Danson ◽  
C E Henderson ◽  
R N Perham
Keyword(s):  
Lipoic Acid ◽  
Pyruvate Dehydrogenase ◽  
Active Site ◽  
Active Sites ◽  
Bacillus Stearothermophilus ◽  
Pyruvate Decarboxylase ◽  
Complex Activity ◽  
Simple Method ◽  
Multienzyme Complexes ◽  
Transition State Analogue

A simple method was developed for assessing the intramolecular coupling of active sites in the lipoate acetyltransferase (E2) component of the pyruvate dehydrogenase multienzyme complexes from Escherichia coli, Bacillus stearothermophilus and ox heart and pig heart mitochondria. Samples of enzyme complex were prepared in which the pyruvate decarboxylase (E1) component was selectively and partly inhibited by treatment with increasing amounts of a transition-state analogue, thiamin thio-thiazolone pyrophosphate. The fraction of the E2 component acetylated by incubation with [2-14C] pyruvate, in the absence of CoA, was determined for each sample of partly inhibited enzyme and was found in all cases to exceed the fraction of overall complex activity remaining. This indicated the potential for transacetylation reactions among the lipoic acid residues within the E2 core. A graphic presentation of the data allowed comparison of the active-site coupling in the various enzymes, which may differ in their lipoic acid content (one or two residues per E2 chain). It is clear that active-site coupling is a general property of pyruvate dehydrogenase complexes of octahedral and icosahedral symmetries, the large numbers of subunits in each E2 core enhancing the effect.

Electrochemical studies of N,N-bis pyrazinyl ­ 3,4,9,10 - perylenebis (dicarboximide) (PyPD ) on Pt electrode

2012 ◽  
Vol 16 (1) ◽  
pp. 53-57 ◽  
Author(s):  
E. H. El-Mossalamy ◽  
A. Y. Obaid ◽  
S. A. El-Daly ◽  
I. S. El-Hallag ◽  
A. M. Asiri ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Platinum Electrode ◽  
Reaction Pathway ◽  
Digital Simulation ◽  
Simulation Method ◽  
Electrode Reaction ◽  
Electrochemical Studies ◽  
Tetrabutylammonium Perchlorate ◽  
Pt Electrode ◽  
Electrochemical Parameters

The electrochemical studies of N, N – bis(pyrazinyl) – 3, 4, 9, 10 – perylene bis (dicarboximide) (PyPD) dye has been carried out on Pt electrode using cyclic voltammetry and convolution deconvolution voltammetry combined with digital simulation technique at a platinum electrode in 0.1 mol L-1 tetrabutylammonium perchlorate (TBAP) in acetonitrile solvent (CH3CN). The compound under consideration was reduced via consumption of two sequential electrons to form radical anion and dianion (EE mechanism). The electrode reaction pathway and the electrochemical parameters of the investigated compound were determined using cyclic voltammetry and convolution – deconvolution transforms. The extracted electrochemical parameters were verified and confirmed via digital simulation method.

Oxidation of chlorophenols on Pt electrode in alkaline solution studied by cyclic voltammetry, galvanostatic electrolysis, and gas chromatography­mass spectrometry

2001 ◽  
Vol 73 (12) ◽  
pp. 1929-1940 ◽  
Author(s):  
Z. Ezerskis ◽  
Z. Jusys
Keyword(s):  
Cyclic Voltammetry ◽  
Platinum Electrode ◽  
Rapid Decrease ◽  
Oxide Formation ◽  
Pt Electrode ◽  
Potential Region ◽  
Galvanostatic Electrolysis ◽  
Diffusion Limitations ◽  
Naoh Solution ◽  
And Diffusion

Potentiodynamic investigations on a platinum electrode show that oxidation of phenol, monochlorophenols, dichlorophenols, 2,3,6-, 2,4,5-, 2,4,6-trichlorophenols, and pentachlorophenol in 1 M NaOH solution, containing 1 mM of phenols, proceeds in the potential region of Pt oxide formation. The oxidation rate of phenols decreases with the increase in the number of chlorine atoms in the benzene ring in the row: phenol > monochlorophenols > dichlorophenols > trichlorophenols > pentachlorophenol. The electrochemical stability of phenols, as studied using a cyclic voltammetry, depends on their chlorination degree and isomerism. Galvanostatic oxidation of 1 M NaOH solutions containing 1 mM of phenol, monochlorophenols, dichlorophenols, 2,3,6-, 2,4,5-, 2,4,6-trichlorophenols, and pentachlorophenol were carried out on a platinum electrode using 30 mA cm­2 current density. The electrolysis of the solutions was performed in the course of 10 h, and concentration of phenols in the anolytes was monitored during oxidation. The concentration of phenolic compounds diminishes from 1 mM to 10­50 mM during 4­5 h of electrooxidation and does not change during further galvanostatic oxidation. A decrease in concentration of phenols during galvanostatic electrolysis weakly depends on the isomerism and a chlorination degree of the compounds. A rapid decrease in concentration of studied phenols during the first 4­5 h of electrolysis and a nonselective oxidation of different chlorophenols suggest that the oxidation proceeds via electrochemically generated oxidants. Further decrease in concentration of phenols is rather small due to deactivation of the electrode as a result of polymerization of corresponding phenols and diffusion limitations.

scholarly journals Carbon Nanotubes/Gold Nanoparticles Composite Film for the Construction of a Novel Amperometric Choline Biosensor

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Baoyan Wu ◽  
Zhongmin Ou ◽  
Xiaojuan Ju ◽  
Shihua Hou
Keyword(s):  
Carbon Nanotubes ◽  
Gold Nanoparticles ◽  
Platinum Electrode ◽  
High Sensitivity ◽  
Silica Sol ◽  
Choline Oxidase ◽  
Good Reproducibility ◽  
Pt Electrode ◽  
Multiwalled Carbon ◽  
Biocompatible Polymer

This study develops a facile method to fabricate a novel choline biosensor based on multiwalled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs). Chitosan, a natural biocompatible polymer, was used to solubilize MWCNTs for constructing the aqueous Chit-MWCNTs solution. Then Chit-MWCNTs were first dropped on the surface of a cleaned platinum electrode. Finally, a thiolated silica sol containing AuNPs and choline oxidase (ChOx) was immobilized on the surface of the Chit-MWCNTs-modified electrode. The MWCNTs/AuNPs/Pt electrode showed excellent electrocatalytic activity for choline. The resulting choline biosensor showed high sensitivity of choline (3.56 μA/mM), and wide linear range from 0.05 to 0.8 mM with the detection limit of 15 μM. In addition, good reproducibility and stability were obtained.

scholarly journals Synthesis and Electrochemical Properties of N-(Ferrocenylmethyl)Aminobenzonitrile and N-(Ferrocenylmethyl)Nitroaniline Derivatives

2015 ◽  
Vol 49 ◽  
pp. 27-34 ◽  
Author(s):  
Chérifa Boubekri ◽  
Abdehamid Khelef ◽  
Belgacem Terki ◽  
Touhami Lanez
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Properties ◽  
Electrochemical Behavior ◽  
Platinum Electrode ◽  
Redox Process ◽  
Ferrocene Derivatives ◽  
Positive Potential ◽  
Formal Potential ◽  
Ferrocenyl Group ◽  
Ft Ir

Seven novel ferrocene derivatives containing (methylamino)benzonitrile and N-methylnitroaniline groups (3a-3f and 4) have been synthesized by conventional methods and characterized by FT-IR, NMR and cyclic voltammetry. The electrochemical behavior of these compounds (3a-3f) has been studied by cyclic voltammetry measurements at a platinum electrode in acetonitrile/0.1 M TBAP. The ferrocenyl group in all compounds showed similar reversible one-electron redox process, suggesting that the ferrocene moieties are equivalent and that there are no interactions among them. The formal potential, , is shifted to the more positive potential, indicating that the (methylamino)benzonitrile and N-methylnitroaniline introduced to ferrocene moiety exercise an electron-withdrawing effect.

Templating synthesis of hollow CuO polyhedron and its application for nonenzymatic glucose detection

2014 ◽  
Vol 2 (20) ◽  
pp. 7306-7312 ◽  
Author(s):  
Chuncai Kong ◽  
Linli Tang ◽  
Xiaozhe Zhang ◽  
Shaodong Sun ◽  
Shengchun Yang ◽  
...  
Keyword(s):  
Detection Limit ◽  
Modified Electrode ◽  
Glucose Sensor ◽  
High Sensitivity ◽  
Fast Response ◽  
Good Stability ◽  
Glucose Detection ◽  
Nonenzymatic Glucose Sensor ◽  
Oxidation Of Glucose ◽  
Templating Synthesis

In this paper, we successfully fabricated a novel type of a hollow CuO polyhedron that consists of numerous nanoplates using Cu2O as a template. The hollow CuO polyhedron-modified electrode exhibits high sensitivity, low detection limit, good stability and fast response towards the oxidation of glucose, suggesting it to be a promising nonenzymatic glucose sensor.

Catalytic Resonance Theory: Parallel Reaction Pathway Control

2019 ◽  
Author(s):  
M. Alexander Ardagh ◽  
Manish Shetty ◽  
Anatoliy Kuznetsov ◽  
Qi Zhang ◽  
Phillip Christopher ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Active Site ◽  
Active Sites ◽  
Reaction Pathway ◽  
Control Strategies ◽  
Oscillation Amplitude ◽  
Catalytic Performance ◽  
Parallel Reaction ◽  
Resonance Theory ◽  
Static Conditions

Catalytic enhancement of chemical reactions via heterogeneous materials occurs through stabilization of transition states at designed active sites, but dramatically greater rate acceleration on that same active site is achieved when the surface intermediates oscillate in binding energy. The applied oscillation amplitude and frequency can accelerate reactions orders of magnitude above the catalytic rates of static systems, provided the active site dynamics are tuned to the natural frequencies of the surface chemistry. In this work, differences in the characteristics of parallel reactions are exploited via selective application of active site dynamics (0 < ΔU < 1.0 eV amplitude, 10<sup>-6</sup> < f < 10<sup>4</sup> Hz frequency) to control the extent of competing reactions occurring on the shared catalytic surface. Simulation of multiple parallel reaction systems with broad range of variation in chemical parameters revealed that parallel chemistries are highly tunable in selectivity between either pure product, even when specific products are not selectively produced under static conditions. Two mechanisms leading to dynamic selectivity control were identified: (i) surface thermodynamic control of one product species under strong binding conditions, or (ii) catalytic resonance of the kinetics of one reaction over the other. These dynamic parallel pathway control strategies applied to a host of chemical conditions indicate significant potential for improving the catalytic performance of many important industrial chemical reactions beyond their existing static performance.

Redox Potential - (Electronic) Structure Relationships in 18- and 17-Electron Mononitrile (or Monocarbonyl) Diphosphine Complexes of Re and Fe

2001 ◽  
Vol 66 (1) ◽  
pp. 139-154 ◽  
Author(s):  
M. Fátima C. Guedes Da Silva ◽  
Luísa M. D. R. S. Martins ◽  
João J. R. Fraústo Da Silva ◽  
Armando J. L. Pombeiro
Keyword(s):  
Cyclic Voltammetry ◽  
Electronic Structure ◽  
Binding Sites ◽  
Closed Shell ◽  
Carbonyl Complexes ◽  
Metal Centre ◽  
Pt Electrode ◽  
Metal Site ◽  
Oxidation Potentials ◽  
First Time

The organonitrile or carbonyl complexes cis-[ReCl(RCN)(dppe)2] (1) (R = 4-Et2NC6H4 (1a), 4-MeOC6H4 (1b), 4-MeC6H4 (1c), C6H5 (1d), 4-FC6H4 (1e), 4-ClC6H4 (1f), 4-O2NC6H4 (1g), 4-ClC6H4CH2 (1h), t-Bu (1i); dppe = Ph2PCH2CH2PPh2), or cis-[ReCl(CO)(dppe)2] (2), as well as trans-[FeBr(RCN)(depe)2]BF4 (3) (R = 4-MeOC6H4 (3a), 4-MeC6H4 (3b), C6H5 (3c), 4-FC6H4 (3d), 4-O2NC6H4 (3e), Me (3f), Et (3g), 4-MeOC6H4CH2 (3h); depe = Et2PCH2CH2PEt2), novel trans-[FeBr(CO)(depe)2]BF4 (4) and trans-[FeBr2(depe)2] (5) undergo, as revealed by cyclic voltammetry at a Pt-electrode and in aprotic non-aqueous medium, two consecutive reversible or partly reversible one-electron oxidations assigned as ReI → ReII → ReIII or FeII → FeIII → FeIV. The corresponding values of the oxidation potentials IE1/2ox and IIE1/2ox (waves I and II, respectively) correlate with the Pickett's and Lever's electrochemical ligand and metal site parameters. This allows to estimate these parameters for the various nitrile ligands, depe and binding sites (for the first time for a FeIII/IV couple). The electrochemical ligand parameter show dependence on the "electron-richness" of the metal centre. The values of IE1/2ox for the ReI complexes provide some supporting for a curved overall relationship with the sum of Lever's electrochemical ligand parameter. The Pickett parametrization for closed-shell complexes is extended now also to 17-electron complexes, i.e. with the 15-electron ReII and FeIII centres in cis-{[ReCl(dppe)2]}+ and trans-{FeBr(depe)2}2+, respectively.

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