Electrochemical Reduction Of Hydrogen Peroxide Research Articles

Flow-Through Amperometric Biosensor System Based on Functionalized Aryl Derivative of Phenothiazine and PAMAM-Calix-Dendrimers for the Determination of Uric Acid.

A flow-through biosensor system for the determination of uric acid was developed on the platform of flow-through electrochemical cell manufactured by 3D printing from poly(lactic acid) and equipped with a modified screen-printed graphite electrode (SPE). Uricase was immobilized to the inner surface of a replaceable reactor chamber. Its working volume was reduced to 10 μL against a previously reported similar cell. SPE was modified independently of the enzyme reactor with carbon black, pillar[5]arene, poly(amidoamine) dendrimers based on the p-tert-butylthiacalix[4]arene (PAMAM-calix-dendrimers) platform and electropolymerized 3,7-bis(4-aminophenylamino) phenothiazin-5-ium chloride. Introduction of the PAMAM-calix-dendrimers into the electrode coating led to a fivefold increase in the redox currents of the electroactive polymer. It was found that higher generations of the PAMAM-calix-dendrimers led to a greater increase in the currents measured. Coatings consisted of products of the electropolymerization of the phenothiazine with implemented pillar[5]arene and PAMAM-calix-dendrimers showing high efficiency in the electrochemical reduction of hydrogen peroxide that was formed in the enzymatic oxidation of uric acid. The presence of PAMAM-calix-dendrimer G2 in the coating increased the redox signal related to the uric acid assay by more than 1.5 times. The biosensor system was successfully applied for the enzymatic determination of uric acid in chronoamperometric mode. The following optimal parameters for the chronoamperometric determination of uric acid in flow-through conditions were established: pH 8.0, flow rate 0.2 mL·min-1, 5 U of uricase per reactor. Under these conditions, the biosensor system made it possible to determine from 10 nM to 20 μM of uric acid with the limit of detection (LOD) of 4 nM. Glucose (up to 1 mM), dopamine (up to 0.5 mM), and ascorbic acid (up to 50 μM) did not affect the signal of the biosensor toward uric acid. The biosensor was tested on spiked artificial urine samples, and showed 101% recovery for tenfold diluted samples. The ease of assembly of the flow cell and the low cost of the replacement parts make for a promising future application of the biosensor system in routine clinical analyses.

The electrochemical reduction of hydrogen peroxide on a palladium-amorphous carbon composite in an alkaline medium

The study of hydrogen peroxide reduction in an alkaline aqueous medium on a composite of palladium particles dispersed in an amorphous carbon matrix (Pd@AC) was performed. Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and X-ray Powder Diffraction (XRD) were used to examine morphology, composition, and crystalline structure. The crystalline structure and size of palladium were analyzed using XRD. The reduction of hydrogen peroxide was studied through cyclic and square-wave voltammetry in an alkaline solution in the absence and presence of dissolved oxygen. The overall electrocatalytic effect of Pd@AC toward hydrogen peroxide reduction strongly depends on the presence of oxygen and the hydrogen peroxide disproportionation reaction in the three-phase system of amorphous carbon, palladium particles, and electrolyte solution.

Rotating ring-disk electrode method to evaluate performance of electrocatalysts in hydrogen peroxide activation via rapid detection of hydroxyl radicals

One-electron electrochemical reduction of hydrogen peroxide (H2O2) is an effective way to produce hydroxyl radical (•OH), whose yield is greatly dependent on the performance (activity and selectivity) of electrocatalysts. However, the current method to evaluate the performance of electrocatalysts is limited by time-consuming and less sensitive method of •OH detection. Herein, we propose an online rotating ring disk electrode (RRDE) method to evaluate the performance of electrocatalysts in H2O2 activation by rapidly detecting •OH. This method is implemented by determining the current signals on the disk and ring electrodes: the generated •OH from H2O2 reduction on the disk electrode (induce negative disk currents) reacts with H2O2 to produce superoxide radical (O2•−), which migrates to and is oxidized on the ring electrode and generates positive ring currents. The relevance of the ring currents to O2•− and •OH is proved by radical quenching tests and kinetic analysis. The performance of five electrocatalysts were evaluated by both the RRDE method and the terephthalic acid (TPA) fluorescence method, and the consistent results verify the applicability of the RRDE method. Hence, this work facilitates the development of high-performance electrocatalysts for H2O2 activation and bring insights for RRDE-based electroanalytic chemistry.

The kinetics of hydrogen peroxide reduction on rare earth doped UO2 and SIMFUEL

The electrochemical reduction of hydrogen peroxide has been studied in sodium chloride solutions containing various anions (bicarbonate/carbonate, sulphate) on Gd-UO2, Dy-UO2 and a SIMFUEL (UO2 doped to simulate spent nuclear fuel). The reaction was observed to proceed via the chemical oxidation of the surface to produce UV followed by its subsequent electrochemical reduction. The reaction was faster on the SIMFUEL surface due to the availability of the oxygen vacancies required to incorporate the OII ions necessary to maintain charge balance. Bicarbonate/carbonate, but not sulphate, was found to suppress peroxide reduction. This could be caused either by peroxide decomposition in solution or by the catalysis of peroxide reformation via the reaction of surface hydroxyl radicals with bicarbonate/carbonate to form carbonate radicals which subsequently decompose by reaction with water. The noble metal particles present in the SIMFUEL appear to play only a minor role in the reduction process.

Cover Feature: Mechanistic Study of the Activation and the Electrocatalytic Reduction of Hydrogen Peroxide by Cu‐tmpa in Neutral Aqueous Solution (15/2021)

The Cover Feature shows an artist impression of the electrochemical reduction of hydrogen peroxide with Cu(tmpa). More information can be found in the Article by M. Langerman and D. G. H. Hetterscheid.

Early sex determination of Ginkgo biloba based on the differences in the electrocatalytic performance of extracted peroxidase

Ginkgo biloba is a dioecious plant. Male ginkgoes are mainly used in landscaping, while females are mainly used for fruit production. However, sex identification of ginkgo is a difficult task, especially at the seedling stage. In this work, we present for the first time the use of electrochemical techniques for the identification of ginkgo sex based on the differences in peroxides within male and female ginkgos. Graphene was used to concentrate peroxides in ginkgo extract, thereby improving electrochemical signal sensitivity. The electrochemical reduction of hydrogen peroxide catalyzed by peroxidase was used as a prob for sex determination in ginkgo. This electrochemical identification technique can be used not only for the analysis of adult ginkgo, but also successfully for the analysis of tissue culture seedlings and live seedlings. This electrochemical sensor has excellent discrimination ability due to the difference in peroxidase content in the leaves and petiole of ginkgo of different sexes. This electrochemical sensor allows for a rapid identification of the sex of ginkgo and has a very strong potential for field analysis.

Electrogenerated chemiluminescence of luminol on a gold nanocluster-graphene-Nafion composite-modified electrode in neutral aqueous solution

The electrogenerated chemiluminescence (ECL) behavior of luminol on a glassy carbon (GC) electrode modified with gold nanocluster-graphene-Nafion composite films has been investigated in neutral aqueous solution (pH 7). In the present study, atomically well-defined gold nanoclusters of Au25(SC6H13)18, where SC6H13 is hexanethiolate, were used for the preparation of composite films. Due to the highly enhanced electrocatalytic activity of the composite towards the reduction of molecular oxygen, strong cathodic luminol ECL response related to the electrochemical oxygen reduction was observed on the composite-modified GC electrode at ca. – 1.34 V vs. Ag/AgCl (3 M NaCl) in a neutral aqueous solution, while no cathodic ECL response was observed on a bare GC electrode. The addition of hydrogen peroxide led to a decrease in the cathodic luminol ECL response related to the oxygen reduction, whereas a new ECL response related to the electrochemical reduction of hydrogen peroxide was observed at ca. – 0.01 V vs. Ag/AgCl (3 M NaCl). The possible ECL mechanisms were discussed. Under the optimum conditions, the ECL response was linear with the concentration of hydrogen peroxide in the range of 1.0 × 10−8 M ~ 4.0 × 10−6 M with a detection limit of 2.21 × 10−9 M (S/N = 3) in neutral aqueous solution.

Electrochemically Reduced Graphene Oxide – Noble Metal Nanoparticles Nanohybrids for Sensitive Enzyme-Free Detection of Hydrogen Peroxide

Electrochemically reduced graphene oxide (ERGO) is a versatile material for the electrode modification, which enables modification of the physicochemical properties of the surface by the reduction and reoxidation of oxygen groups. The oxygen functional groups and structural defects of ERGO deposited on a layer of metal nanoparticles facilitate the electron transport and enhance the electrocatalytic properties of the nanoparticles. ERGO layers show moderate-intrinsic electrocatalytic properties towards the electrochemical reduction of hydrogen peroxide. In this contribution, we present studies of ERGO layers on the top of the nanoparticle layer composed of gold nanoparticles stabilized with silicotungstate ligands (Au/SiW12), silver nanoparticles stabilized with silicotungstate ligands (Ag/SiW12), and silver nanoparticles stabilized with phosphomolybdate ions (Ag/PMo12). The nanoparticles are prepared by the reduction of the chloroauric acid or silver nitrate by the partially reduced forms of H4SiW12O40 or H3PMo12O40 acid. The films of nanoparticles are conditioned by the repetitive potential cycling at pH = 6 before the deposition of the graphene oxide (GO) layer. The GO layer is reduced by scanning the potential between − 0.4 and − 1.2 V vs. SCE. Combination of ERGO with Au/SiW12 or Ag/SiW12 nanoparticles results in synergistic enhancement of amperometric responses to hydrogen peroxide. The electrocatalytic current values observed for the NPs-ERGO layers are higher than the sum of the current for the pure NPs layers and the ERGO layer deposited on a glassy carbon electrode. The Ag/PMo12 nanoparticles show poor electrocatalytic currents due to possible formation of aggregate structures. Infrared and Raman spectroscopies are applied to investigate the electrocatalytic layers.

Co2TiO4/Reduced Graphene Oxide Nanohybrids for Electrochemical Sensing Applications.

For the first time, the synthesis, characterization, and analytical application for hydrogen peroxide quantification of the hybrid materials of Co2TiO4 (CTO) and reduced graphene oxide (RGO) is reported, using in situ (CTO/RGO) and ex situ (CTO+RGO) preparations. This synthesis for obtaining nanostructured CTO is based on a one-step hydrothermal synthesis, with new precursors and low temperatures. The morphology, structure, and composition of the synthesized materials were examined using scanning electron microscopy, X-ray diffraction (XRD), neutron powder diffraction (NPD), and X-ray photoelectron spectroscopy (XPS). Rietveld refinements using neutron diffraction data were conducted to determine the cation distributions in CTO. Hybrid materials were also characterized by Brunauer–Emmett–Teller adsorption isotherms, Scanning Electron microscopy, and scanning electrochemical microscopy. From an analytical point of view, we evaluated the electrochemical reduction of hydrogen peroxide on glassy carbon electrodes modified with hybrid materials. The analytical detection of hydrogen peroxide using CTO/RGO showed 11 and 5 times greater sensitivity in the detection of hydrogen peroxide compared with that of pristine CTO and RGO, respectively, and a two-fold increase compared with that of the RGO+CTO modified electrode. These results demonstrate that there is a synergistic effect between CTO and RGO that is more significant when the hybrid is synthetized through in situ methodology.

Electrogenerated hydrophilic carbon nanomaterials with tailored electrocatalytic activity

This work investigates the influence of the type of buffer electrolyte used in the generation of Electrochemical Hydrophilic Carbon (EHC) on their physical-chemical properties and electrocatalytic activity. The EHC nanomaterials were prepared in three different biological buffers, phosphate, glycine and citrate buffers (EHC@phosphate, EHC@glycine, EHC@citrate) and their surface properties were fully characterized by AFM, XPS and Raman. The EHC nanomaterials drop cast onto a glassy carbon electrode were electrochemically characterized in [Fe(CN)6]3-/4- and [Ru(NH3)6]3+/2+ redox probes solutions, and their electrocatalytic activity was investigated towards hydrogen peroxide and oxygen reduction reactions (ORR) in a phosphate buffer solution. It was found that the nature of buffer electrolyte strongly influences the surface chemical state of the EHC materials, disorder degree in the hexagonal sp2 carbon network and oxygen functional groups, affecting both the EHC electrocatalytic activity towards the ORR and H2O2 reduction reaction. The most catalytic material for the ORR was EHC@citrate, whereas EHC@glycine showed the highest oxygen conversion (n ≅ 2.7 to 3). Moreover, it was shown that the content of oxygen singly bonded to carbon correlates strongly with the number of electrons transferred.A very singular behaviour in the electrochemical reduction of hydrogen peroxide was observed on EHC@glycine, qualitatively interpreted as an autocatalytic reaction. In contrast, a blocking-like effect was depicted on EHC@phosphate. These results must have an important impact in the development of materials with peroxidase-like activity and in the design of O2 sensors with non-sensitivity to H2O2.

Electrochemical oxygen reduction on layered mixed metal oxides: Effect of B-site substitution

Oxygen reduction reaction (ORR) is critical in advancing the frontiers of electrochemical energy conversion and storage technologies. To date, Pt-based electrocatalysts exhibit state-of-the-art performance for low temperature ORR, but are hindered by their high cost. Therefore, it is imperative to find cost-effective alternatives for the practical realization of these technologies. Herein, we investigate the effect of layered, mixed metal oxides belonging to first-series Ruddlesden-Popper (R-P) phases with a general composition of A2BO4 (A=rare earth/alkaline earth metals; B=3d transition metal) for ORR in alkaline enviroment of anion exchange membrane fuel cells. We show that the nature of the B-site 3d transition metal in these oxides is critical in tuning the ORR activity. Using a combination of well-controlled synthesis, chemical, as well as electrochemical studies, we find that substitution of the Ni B-site in these oxides with nominal amounts of Mn and Co (La2Ni0.88Mn0.12O4 and La2Ni0.88Co0.12O4, respectively) leads to enhanced overall ORR activity by selective promotion of the electrochemical reduction of hydrogen peroxide, an intermediate in the pseudo 4e− ORR path. The reported findings can be used in designing nonprecious metal-based oxide electrocatalysts for oxygen reduction in alkaline anion exchange memebrane fuel cells.

Patchy gold coated Fe3O4 nanospheres with enhanced catalytic activity applied for paper-based bipolar electrode-electrochemiluminescence aptasensors

In this work, novel multifunctional patchy gold coated Fe3O4 hybrid nanoparticles (PG-Fe3O4 NPs) have been successfully synthesized in aqueous medium via a facile adsorption-reduction method. A rational formation mechanism has been proposed by monitoring the morphological evolution. The PG-Fe3O4 NPs retained the good magnetic property and exhibited excellent catalytical effeciency towards the electrochemical reduction of hydrogen peroxide. Chronoamperometric and amperometric experiments indicated a relatively high catalytic rate constant of 3.13 × 105 M−1 s−1, a high sensitivity of 578.87 µA mM−1 cm−2 and a low Michaelis-Menten constant of 462 µM. Meanwhile, the introduction of patchy gold could help biofunctionalization via Au-S bond for different biodetection and biosensing purposes. Here, as an example, thiol-terminated aptamers were immobilized onto the patchy gold part as a signal probe to detect carcinoembryonic antigen (CEA). A related paper-based bipolar electrode-electrochemiluminescence (pBPE-ECL) aptasensor was fabricated as the low-cost, disposable and miniature platform. To improve the sensitivity, Au nanodendrites were electrodeposited at the BPE cathode as the matrix for Apt1 immobilization. This aptasensor showed a wide linear range of 0.1 pg mL−1–15 ng mL−1 with a low detection limit of 0.03 pg mL−1, remaining competitive against other ones, and also demonstrating the PG-Fe3O4 NPs have promising potential for catalysis and bioassays.

Palladium nanoparticles immobilized on polymer-functionalized magnetic nanoparticles for the determination of hydrogen peroxide

In this paper, the application of palladium nanoparticles supported on hyperbranched poly (ethylene glycol)-block-poly(citric acid)-functionalized Fe3O4 magnetic nanoparticles (Pd@PCA-b-PEG-Fe3O4) were evaluated as a new electrocatalyst in electrochemical sensing. The Pd@PCA-b-PEG-Fe3O4 was immobilized on the surface of a glassy carbon electrode (GCE) for the electrochemical reduction of hydrogen peroxide (H2O2). This electrode material was characterized by scanning electron microscopy (SEM), the transmission electron microscopy (TEM), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The Pd@PCA-b-PEG-Fe3O4 showed good electrocatalytic activity toward the reduction of H2O2 in the neutral phosphate buffer solution (pH 7.0). Moreover, the potential utility of the sensor was demonstrated by applying it to the analytical determination of H2O2 concentration. The results showed that the electrocatalytic current increased linearly with the H2O2 concentration in the range of 0.1–50.0 µM and the detection limit was 0.03 µM. Finally, the sensor has been successfully applied to determine H2O2 in water and urine samples with good accuracy and precision.

Nitrogen-doped graphene prepared by a millisecond photo-thermal process and its applications

Doping graphene with heteroatoms such as nitrogen is a significant strategy to improve its electrochemical performance. Here, a unique millisecond photo-thermal process which is simple, safe for preparing N-doped Graphene (NG) under ammonia atmosphere was adopted. The obtained NGs were characterized by X-ray photoelectron spectroscopy (XPS), Raman spectra, Scanning Electron Microscope (SEM), and electrochemical techniques. The nitrogen content of the NG can as 14 times as that of original rGO according to the XPS results. The intensity ratio of D band to G band in Raman spectra is increased from 1.12 to 1.18, which also demonstrates the doping of nitrogen atoms and creation of some structure defects. The SEM picture clearly demonstrates that the space between graphene planes was significant enlarged. Furthermore, nitrogen adsorption/desorption test indicated that the specific surface area of NG (267.3 m2 g−1) is much higher than that of original rGO (198.9 m2 g−1), which indicates more surfaces are available after photo-thermal process. The electro-catalysis activity of the NG was characterized by electrochemical reduction of hydrogen peroxide (2 electron process) and oxygen (4 electron process). The hydrogen peroxide reduction potential at the NG electrode was 200 mV positive shift and the peak current increase 15 times compare to bare glassy carbon electrode. The oxygen reduction reaction (ORR) testes shows an obvious reductive peak in −0.39 V vs Ag/AgCl on the NG electrode, which demonstrated that the NG also has the catalysis effect on four-electron process. As well as that, the obtained NG was also used to assemble supercapacitances, it was found that the specific capacitance of NG achieved as high as 350 F g-1 with well cyclic stability and rate capability.

The mechanism of electrochemical reduction of hydrogen peroxide on silver nanoparticles.

The reduction of hydrogen peroxide on a silver nanoparticle modified boron doped diamond electrode in a neutral solution is shown to proceed through a CE mechanism. Hydrogen peroxide undergoes a disproportionation reaction to form oxygen (and water) on the silver surface, creating a diffusion layer of oxygen, which, at a sufficiently biased electrode, is then reduced to hydrogen peroxide. Voltammetry and a full mechanistic simulation are undertaken to confirm the mechanism, showing at short times a dependence of the reductive signal on waiting time prior to voltammetric analysis reflecting the extent of the disproportionation step which occurs prior to voltammetric analysis.

Raman spectroelectrochemical study of electrode processes at hybrid polyaniline - copper hexacyanoferrate modified electrode

Electrochemical redox processes taking place within a hybrid polyaniline (PANI) and copper hexacyanoferrate (CuHCF) modified electrode, as well as of solution species at the surface of a modified electrode, have been investigated by near-infrared laser (785nm) induced Raman spectroscopy. It has been shown that the composite CuHCF-PANI layers can be obtained at electrode surface by first covering the electrode by CuHCF layer using potential cycling procedure, followed by electropolymerization of aniline onto this layer at a controlled electrode potential. A reverse in this order does not result in a composite layer. Raman bands observed within a broad spectral range, as well as their dependence on electrode potential, have been analyzed. Electrochemically driven changes in spectral features related to redox transformations both of PANI and CuHCF have been observed and discussed. Slow redox transformations have been noted, most probably related to slow charge transfer within these hybrid layers. Electrochemical reduction of hydrogen peroxide at a hybrid modified electrode occurs through the redox mediation of CuHCF, whereas PANI remains not involved in this process.

Enhanced electrochemical reduction of hydrogen peroxide by Co3O4 nanowire electrode

Crystalline Co3O4 nanowire arrays with different morphologies grown on Ni foam were investigated by varying the reaction temperature, the concentration of precursors, and reaction time. The Co3O4 nanowires synthesized under typical reaction condition had a diameter range of approximately 500–900 nm with a length of 17 µm. Electrochemical reduction of hydrogen peroxide (H2O2) of the optimized Co3O4 nanowire electrode was studied by cyclic voltammetry. A high current density of 101.8 mA cm−2 was obtained at −0.4 V in a solution of 0.4 M H2O2 and 3.0 M NaOH at room temperature compared to 85.8 mA cm−2 at −0.35 V of the Co3O4 nanoparticle electrode. Results clearly indicated that the Ni foam supported Co3O4 nanowire electrode exhibited superior catalytic activity and mass transport kinetics for H2O2 electrochemical reduction.

Simultaneous growth of spherical, bipyramidal and wire-like gold nanostructures in solid and solution phases: SERS and electrocatalytic applications

Anisotropic growth of Au nanostructures including bipyramidal and nanowires on ITO substrate was achieved byin situelectrochemical reduction of Au+ions from the growth solution. The AuNS grown ITO substrates were utilized for SERS and electrochemical reduction of hydrogen peroxide.

Electrochemical reduction of hydrogen peroxide by nanostructured hematite modified electrodes

Structure-dependent selectivity of an α-Fe2O3|FePO4 based electrochemical H2O2 sensor against dissolved O2 is reported.

Tuning the composition of gold–silver bimetallic nanoparticles for the electrochemical reduction of hydrogen peroxide and nitrobenzene

Gold@silver core–shell nanoparticles were synthesized by galvanic displacement reaction and modified on glassy carbon electrode for the reduction of hydrogen peroxide and nitrobenzene.