H2O2 Electrogeneration Research Articles

Electrochemically generated sulfate radicals by boron doped diamond and its environmental applications

Oxidation of recalcitrant organic contaminants via the electrogenerated sulfate radicals (SO4−) with boron doped diamond (BDD) electrode is one of the most efficient techniques. In this review, fundamental mechanisms of sulfate (SO42−), persulfate (PS, S2O82−) and peroxymonosulfate (PMS, HSO5−) activation with BDD anode and its environmental applications are discussed. Significance of BDD electrode properties such as sp3/sp2 ratio, doping agents and substrate material, and the influence of electrolyte medium, current density and the presence of other inorganic ions (chloride, carbonate, nitrate, phosphate) on the electrogeneration of reactive sulfate species and its reactivity is comprehended as followingly, (i) BDD-sulfate process explains the fundamental reaction mechanisms involving in the electrogeneration of SO4−and S2O82− via radical and non-radical routes, (ii) electrochemical activation of electrogenerated/externally added PS and PMS via the direct/indirect pathways and its promotional reactions are detailed, and (iii) mode of reactivity of the electrogenerated reactive sulfate species with organic contaminants in synthetic and real water, wastewater and soil matrices is elaborated. Most of the studies reported the activation of SO42− at current densities ≥10 mA cm−2, and the energy consumption in the range of 41–190 kW h m−3 was reported for the treatment (95–100% removal efficiency) of high organic content real wastewaters. In later section, the importance of coupling other processes such as electrogeneration of H2O2, UV irradiation, and membrane distillation with BDD/sulfate system to enhance the performance efficiency is discussed. Future perspectives of the research and application is presented at the end.

Degreasing cotton used as pore-creating agent to prepare hydrophobic and porous carbon cathode for the electro-Fenton system: enhanced H2O2 generation and RhB degradation.

A porous carbon cathode was prepared using graphite, polytetrafluoroethylene (PTFE), and degreasing cotton (DC) through sintering treatment. The carbonization of DC by heat treatment played an ideal role in pore-creating, which weakened the mass transfer resistance of O2, and as a result, the adoption of degreasing cotton significantly improved the performance of H2O2 electro-generation. The optimized cathode was able to generate 567 mg L-1 H2O2 with a current efficiency (CE) of 86.7% by the electrochemical reaction of 60 min in a divided reactor. Furthermore, the degradation of rhodamine B (RhB) was carried out by an electro-Fenton system using the optimal cathode selected. The developed electro-Fenton system exhibited an excellent RhB degradation performance. The RhB solution of 50 mg L-1 was decolorized completely by the treatment of 10 min. Moreover, the degradation of 50~90 mg L-1 RhB solution presented over 90% TOC removal by the treatment of 120 min, indicating the ideal mineralization of organic pollutants. In addition, it was found that •OH was the major oxidizing specie responsible for the organics degradation. Finally, the possible pathway of RhB degradation in the electro-Fenton system was proposed by GC-MS analysis. The adoption of natural fibers for pore-creating provides an innovative and low-cost method to prepare porous cathode, which may promote the application of electro-Fenton oxidation in wastewater treatment.

Effect of electrochemically-driven technologies on the treatment of endocrine disruptors in synthetic and real urban wastewater

While it remains a challenging task, having a fundamental understanding of the influence of water matrix composition is of central importance for the removal of pollutants in electrochemical treatment processes. This work studied the effect of the complexity of different water matrices on the removal of endocrine disruptors using different electrochemical advanced oxidation processes (EAOPs) based on H2O2 electrogeneration. The study helped improve the understanding of synthetic and real urban wastewater, and the effective mechanisms for the treatment of pollutants in these effluents. The results obtained showed that, regardless of the medium applied, there was an increase in pollutants mineralization in the following order, based on the EAOPs method employed: electrochemical oxidation with H2O2 electrogeneration (EO-H2O2) < electro-Fenton (EF) < photoelectro-Fenton (PEF). Despite the slower degradation kinetics of the EO-H2O2 process, its wider pH range makes it suitable for implementation. Aside the degradation/mineralization performance of the EO-H2O2 process, a time-course analysis was conducted on the nitrogen and chloride-based ions in the solution investigated since their presence is vital for determining the final use of the treated effluents based on the parameters of water quality. These parameters include the established maximum concentration levels of the compounds in the water matrix allowed for human consumption or the legal limits of discharge for wastewater treatment facilities. The findings help shed light on the role of coexisting species in water matrix, since this affects the efficiency and competitiveness of EAOPs. Clearly, having detailed knowledge of the water matrix composition will help one to have a better understanding of EAOPs, and this will enable to obtain higher degradation levels in water treatment processes.

Synergetic electrocatalytic degradation of isophorone by active oxygen species generated in the gas diffusion electrode and PbO2 anode

Significant efforts have been made to achieve efficient H2O2 generation via oxygen reduction reaction (ORR). Here, the acetylene black (AB)-based gas diffusion electrodes (GDEs) modified by PTFE were fabricated and applied in a closed autoclave for H2O2 generation for the first time. The surface morphology, BET, XPS, cyclic voltammetry curves and linear scanning voltammetry curves of GDEs were all characterized. Additionally, the H2O2 generation experiments of GDEs and the relationship between H2O2 yield and BET surface area (SBET), double layer capacitance (Cdl) were all investigated. It could be found that the SBET and Cdl of GDEs kept a good linear relationship with H2O2 content, and 2#GDE (AB:PTFE = 1:3) possessed the optimal H2O2 generation capacity. Also, the effect of oxygen pressure and current density on H2O2 production was evaluated detailedly, indicating higher oxygen pressure was beneficial to the H2O2 generation and the preferable current density was 20 mA cm−2 due to the side reactions. And all the H2O2 electro-generation experiments exhibited a higher oxygen utilization efficiency (0.77%–2.93%). Finally, the efficient and synergetic electro-catalytic degradation of isophorone was achieved by self-made PbO2 anode and GDE.

Design Strategies of Non-Noble Metal-Based Electrocatalysts for Two-Electron Oxygen Reduction to Hydrogen Peroxide.

Hydrogen peroxide (H2 O2 ) is a highly value-added and environmentally friendly chemical with various applications. The production of H2 O2 by electrocatalytic 2e- oxygen reduction reaction (ORR) has drawn considerable research attention, with a view to replacing the currently established anthraquinone process. Electrocatalysts with low cost, high activity, high selectivity, and superior stability are in high demand to realize precise control over electrochemical H2 O2 synthesis by 2e- ORR and the feasible commercialization of this system. This Review introduces a comprehensive overview of non-noble metal-based catalysts for electrochemical oxygen reduction to afford H2 O2 , providing an insight into catalyst design and corresponding reaction mechanisms. It starts with an in-depth discussion on the origins of 2e- /4e- selectivity towards ORR for catalysts. Recent advances in design strategies for non-noble metal-based catalysts, including carbon nanomaterials and transition metal-based materials, for electrochemical oxygen reduction to H2 O2 are then discussed, with an emphasis on the effects of electronic structure, nanostructure, and surface properties on catalytic performance. Finally, future challenges and opportunities are proposed for the further development of H2 O2 electrogeneration through 2e- ORR, from the standpoints of mechanistic studies and practical application.

Coupling effect of nitrogen-doped carbon black and carbon nanotube in assembly gas diffusion electrode for H2O2 electro-generation and recalcitrant pollutant degradation

The generation of H2O2 on cathode is a pivotal and rate-limiting step in the electrocatalytic oxygen reduction reaction process. In this work, carbon nanotube (CNT) and nitrogen-doped carbon black (NCB) was assembled on carbon fiber cloth to achieve high oxygen reduction reaction (ORR) efficiency in gas diffusion electrode (GDE). An excellent and stable H2O2 generation capacity of 42.15 mg L−1h−1 cm−2 was achieved, and 39.6% TOC removal and complete decolorization over a wide pH range were realized for recalcitrant Reactive Red X-3B in modeling wastewater. The involved reactive oxygen species were found to be H2O2, 1O2 and •OH. Besides density functional theory calculations, the coupling effect of various components in the GDE on electrocatalytic activity was investigated based on characterization and electrochemical examinations. It was revealed that pyridinic N and pyrrolic N in NCB and electron transfer of CNT increased the electrocatalytic activity and selectivity for two-electron ORR. In addition, the gradient hydrophobic three-phase-boundary increased oxygen retention and ORR activity for H2O2 generation. The reusability test of CNT/NCB-GDE showed its great applicability for H2O2 electro-generation and wastewater treatment.

Carbon-based cathodes degradation during electro-Fenton treatment at pilot scale: Changes in H2O2 electrogeneration

Autopsy of carbon-PTFE cathodes was performed by addressing their degradation in a commercial plate-and-frame cell equipped with a Nb-BDD anode. Cell is arranged within an electrochemical pilot plant designed for treating wastewaters by electrochemical Fenton-like processes, thus an efficient electrocatalytic production of H2O2 is necessary to guarantee Fenton’s reaction. Significant decrease in H2O2 electrogeneration occurred during pilot plant operation, hindering the efficient performance of Fenton-like processes. Two cathodes were studied, first was operated at pH 3 and second at neutral pH by using EDDS as complexing agent to maintain iron in solution. Electrogenerated H2O2 decreased from 43 mg L−1 to 16 mg L−1 in the first cathode after 50 h of operation and from 49 mg L−1 to 24 mg L−1 in the second one after 26 h of operation. Both were cleaned with 30% (v/v) solution of HCl/water for 24 h and H2O2 production was recovered only in the second cathode (able to generate 39 mg L−1). Autopsy of the cathodes was tackled by scanning electron microscopy (SEM) and X-ray energy dispersive (EDX), evidencing a strong degradation of first cathode surface and iron oxide inlays in second one due to the decomposition of Fe3+:EDDS and consequent iron precipitation at neutral pH.

Degradation of refractory organics in dual-cathode electro-Fenton using air-cathode for H2O2 electrogeneration and microbial fuel cell cathode for Fe2+ regeneration

The electrogeneration of H2O2 and electro-regeneration of ferrous are conflicting matters in electro-Fenton system. In this research, the degradation of Rhodamine B, methyl orange (MO) and 4-chlorophenol (4-CP) was investigated using a novel dual-cathode microbial fuel cell (MFC) electro-Fenton (EF) hybrid system. An air-cathode of an EF system was used for H2O2 electrogeneration and a carbon felt cathode of a MFC was used to accelerate Fe2+ regeneration. Synergistic improvement of MFC power generation and the degradation of the above refractory organics through EF reaction was achieved. The EF air-cathode was fabricated by adopting activated carbon/graphite powder mixture and PVDF binder, which showed higher H2O2 generation but slower Fe3+ reduction rate than MFC carbon felt cathode. The Rhodamine B removal rate constant and mineralization current efficiency of the MFC coupled EF were 64% and 42% higher than that of uncoupled EF, respectively. The MFC-EF coupled system also exhibited significantly higher removal efficiency for MO and 4-CP than that of un-coupled EF system. Moreover, the power density of MFC was greatly enhanced by coupling EF due to higher Fe3+/Fe2+ redox potential than oxygen reduction.

In situ electrogeneration and activation of H2O2 by atomic Fe catalysts for the efficient removal of chloramphenicol

Heterogeneous electron-Fenton processes have been regarded as promising, environmentally friendly techniques for the removal of refractory organics. A new strategy has been brought forward for an electron-Fenton-like process with in situ H2O2 production, but regarding the catalysts, their geometric stability, H2O2 selectivity, and applicability under high pH values still need to be improved. Herein, bifunctional catalysts were proposed for a heterogeneous Fenton-like reaction by introducing Fe atoms into defect-enriched graphene sheets (Fe/N-DG). The structural and compositional results suggested that the excellent dispersing stability of Fe atoms is mainly attributed to the abundant pyridinic-N sites. Optimized Fe1/N-DG exhibited superior mass activity (5.28 A mgFe−1 at 0.6 V vs. RHE) and H2O2 selectivity (86%) under the synergistic effects of Fe‒N and Fe‒O sites. The Fe/N-DG catalysts maintained superior activities for chloramphenicol removal, even under extreme pH conditions (pH≤4 or pH≥10). Of these catalysts, Fe1/N-DG with a predominant Fe-N structure exhibited the best catalytic performance, achieving the complete removal of chloramphenicol within 180 min under alkaline conditions. The possible mechanism for chloramphenicol removal under alkaline conditions was proposed, along with those for the production and activation of H2O2. This study gives new insights into atomic Fe-based catalysts exhibiting excellent selectivity and stability for antibiotic wastewater treatment.

O-doped graphitic granular biochar enables pollutants removal via simultaneous H2O2 generation and activation in neutral Fe-free electro-Fenton process

H2O2 generation by 2-electron oxygen electroreduction reaction (2eORR) has attracted great attention as an alternative to the industry-dominant anthraquinone process. Electro-Fenton (EF) process, which relies on the H2O2 electrogeneration, is regarded as an important environmental application of H2O2 generation by 2eORR. However, its application is hindered by the relatively expensive electrode materials. Proposing cathode materials with low cost and facile synthetic procedures are the priority to advance the EF process. In this work, a composite cathode structure that uses graphitic granular bamboo-based biochar (GB) and stainless steel (SS) mesh (GBSS) is proposed, where SS mesh functions as current distributor and GB supports synergistic H2O2 electrogeneration and activation. The graphitic carbon makes GB conductive and the oxygen-containing groups serve as active sites for H2O2 production. 11.3 mg/L H2O2 was produced from 2.0 g GB at 50 mA after 50 min under neutral pH without external O2/air supply. The O-doped biochar further increased the H2O2 yield to 18.3 mg/L under same conditions. The GBSS electrode is also effective for H2O2 activation to generate OH, especially under neutral pH. Ultimately, a neutral Fe-free EF process enabled by GBSS cathode is effective for removal of various model organic pollutants (reactive blue 19, orange II, 4-nitrophenol) within 120 min, and for their partial mineralization (48.4–63.5%). Long-term stability of the GBSS electrode for H2O2 electrogeneration, H2O2 activation, and pollutants degradation were also examined and analyzed. This work offers a promising application for biomass waste for removals of organic pollutants in neutral Fe-free EF process.

Electro-Fenton oxidation of a β-lactam antibiotic cefoperazone: Mineralization, biodegradability and degradation mechanism

Oxidation of a commonly-used β-lactam pharmaceutical, cefoperazone (CFPZ), was systematically investigated by anodic oxidation (AO), AO in presence of H2O2 electro-generation (AO-H2O2) and electro-Fenton (EF) processes with an activated carbon fiber cathode from the biodegradability viewpoint. The degradation and mineralization rates increased in a sequence of AO < AO-H2O2 < EF. Even CPFZ could be efficiently degraded in EF process, achieving complete CFPZ mineralization was rather difficult. Thereby, the biodegradability of the effluent after electrochemical pretreatment was examined to test the feasibility of the combination of electrochemical and biological processes. The results suggested that compared with AO and AO-H2O2, EF process could effectively transform the non-biodegradable CFPZ into biocompatible materials with a high BOD5/COD value (0.33 after 720 min), allowing the possible biotreatment for further remediation. This behavior was relatively accorded with the average oxidation state (AOS) results, evidencing the potential of EF process in enhancing the biodegradability of CFPZ. The determination of inorganic ions revealed that N in CFPZ molecular was oxidized into NH4+ and NO3− ions in EF process. Oxalic, succinic, oxamic, fumaric and formic acids were also formed. Besides, six aromatic by-products were qualified and a possible pathway involving hydrolysis, hydroxylation and decarboxylation during CFPZ mineralization was proposed.

Electrochemical removal of RRX-3B in residual dyeing liquid with typical engineered carbonaceous cathodes

Electro-catalytic activities of carbonaceous cathodes including graphite plate, graphite felt, carbon felt, activated carbon felt (ACF) and carbon fiber felt (CFF) for degradation of Reactive Red X–3B (RRX-3B) in residual dyeing liquid were compared. The best electrochemical performance was obtained using dimensional stable anode (DSA) and CFF cathode due to the higher capacity for electro-generation of H2O2 by selective two-electron oxygen reduction. The CFF/DSA electrolysis system realized 78.2% COD removal and complete decolorization over a wide pH range. The efficacy of RRX-3B degradation was found to be dependent on the nature of carbonaceous materials. Electrochemical measurements showed that CFF possessed higher electrochemical surface area and hydrogen evolution reaction over-potential. Furthermore, the intrinsic graphitic N in CFF was proved to be catalytic active site by DFT calculations. Reactive Red X–3B degradation intermediates with benzene structures and carboxylic acids via hydroxylation in RRX-3B oxidation were identified by GC-MS. It was found that S/Cl/N-containing groups in RRX-3B molecule were mineralized to SO42−, NO3− and Cl− ions in the electrolysis.

Electrogeneration of H2O2 utilizing anodic O2 on a polytetrafluoroethylene-modified cathode in a flow-through reactor

Efficient electrogeneration of hydrogen peroxide (H2O2) is critical for treatment of refractory pollutants by the electro-Fenton process. An effective strategy is developed by combining a flow-through reactor with a polytetrafluoroethylene (PTFE)-modified graphite felt cathode. In this design, anodic oxygen is directly used for efficient H2O2 generation at the modified cathode. Experimental results show that the modified cathode with the optimum PTFE content can produce 29.6 mg/L of H2O2, which is 16 times higher than the unmodified graphite felt cathode for a flow rate of 3 mL/min. Maximum H2O2 production, up to 30.7 mg/L, was obtained under the following conditions: 120 mA, 3 mL/min, initial pH 13, no external aeration.

Catalysis of oxygen reduction reaction for H2O2 electrogeneration: The impact of different conductive carbon matrices and their physicochemical properties

Carbon-based catalysts are widely used in oxygen reduction reactions (ORR) via 2e- for H2O2 electrogeneration. The direct comparability of the structural proprieties of different carbon matrices applied on ORR, however, has never been tested. Here, we evaluate how the electrochemical and structural properties of different carbon-based materials, including carbon Printex XE2B (PXE2BC), Printex L6 (PL6C), carbon derived from lignin (LIGC), graphite (GRA) and glassy carbon (GC), affect on ORR. All the materials were characterized by Raman spectroscopy, X-ray photoelectron spectrometry (XPS), elementary analysis, field emission gun scanning electron microscopy, surface area measurements and electrochemical assays for the evaluation of ORR. Notably, the morphology, the size of the particles and the types of functional groups present in the structure of carbon materials were keys in the efficiency of ORR. The carbon materials PL6C and PXE2BC with high surface area and oxygenated functional groups in their structure displaced the ORR potential, facilitating the reaction. Carbon materials with less surface area, such as GRA, LIGC and GC, and whose main functional groups in their structures were non-oxygenated or nitrogenated, were less active in ORR. The displacement of the potential and the efficiency of H2O2 generation were directly dependent on the electrochemical and structural characteristics of the materials used as catalysts. These results are particularly relevant regarding a proper choice of carbon catalyst can increase the efficiency of ORR.

Mineralization of Methyl Orange azo dye by processes based on H2O2 electrogeneration at a 3D-like air-diffusion cathode

This work addresses the mineralization of the widely used Methyl Orange (MO) azo dye by technologies based on H2O2 electrogeneration at a 3D-like air-diffusion cathode. These include two Fe2+-catalyzed processes such as electro-Fenton (EF) and photoelectro-Fenton (PEF). Bulk electrolyses were performed in a recirculation flow plant, in which the Eco-Cell filter-press electrochemical reactor was connected in series with a UVA photoreactor. The former reactor was equipped with a Ti|Ir–Sn–Sb oxide plate anode alongside a 3D-like air-diffusion cathode made from graphite felt and hydrophobized carbon cloth, aimed at electrogenerating H2O2 on site. The influence of current density (j), volumetric flow rate (Q) and initial MO concentration was examined. The greatest oxidation power corresponded to PEF process. The best operation conditions to treat 30 mg L−1 of total organic carbon of MO in a 50 mM Na2SO4 solution by PEF were found at 0.50 mM Fe2+, pH 3.0, j = 20 mA cm−2 and Q = 2.0 L min−1, obtaining 100% and 94% of color and TOC removals at 30 and 240–300 min, respectively. This accounted for 35% of mineralization current efficiency and 0.12 kWh (g TOC)−1 of energy consumption at the end of the electrolysis. The oxidation power of EF and PEF was compared with that of anodic oxidation (AO), and the sequence obtained was: PEF > EF > AO. The dye was gradually degraded, yielding non-toxic short carboxylic acids, like maleic, fumaric, formic, oxalic and oxamic, whose Fe(III) complexes were rapidly photolyzed.

Electrochemical generation of H2O2 using gas diffusion electrode improved with rGO intensified with the Fe3O4/GO catalyst for degradation of textile wastewater

This study aimed to evaluate the efficiency of an electro-Fenton system, using a gas diffusion electrode (GDE) modified with reduced graphene oxide (rGO) for the electrogeneration of H2O2. The process was intensified using magnetic nanoparticles (Fe3O4) supported in graphene oxide (GO) as high-performance heterogeneous Fenton-like catalyst for degradation of textile wastewater. The GDE composed by carbon/PTFE produced 116.0 mg L−1 of H2O2. The modification of GDE with 5 % of rGO increased by about 83.0 % in the H2O2 generation (from 116.0–212.0 mg L−1). The catalyst modified with 15 % of GO presented in the high reduction of turbidity (98.5 %), COD (81.7 %) and TOC (70.3 %) and an excellent stability during ten cycles of reuse. The GO in addition to providing Fe3O4 stability also contributes to the generation of hydroxyl radicals (OH). The in situ H2O2 generation combined with a reusable catalyst made the process more efficient, economical and eco-friendly.

Engineered FeVO4/CeO2 nanocomposite as a two-way superior electro-Fenton catalyst for model and real wastewater treatment

FeVO4/CeO2 was applied in the electro-Fenton (EF) degradation of Methyl Orange (MO) as a model of wastewater pollution. The results of the characterization techniques indicate that FeVO4 with triclinic structure and face-centered cubic fluorite CeO2 maintained their structures during the nanocomposite synthesis. The effect of applied current intensity, initial pollutant concentration, initial pH, and catalyst weight was investigated. The MO removal reached 96.31% and chemical oxygen demand (COD) removal 70% for 60 min of the reaction. The presence of CeO2 in the nanocomposite plays a key role in H2O2 electro-generation as a significant factor in the electro-Fenton (EF) system. The metal leaching from FeVO4/CeO2 was negligible (cerium 4.1%, iron 4.3%, and vanadium 1.7%), which indicates that the active species in the nanocomposite are strongly interacting with each other and are stable. The performance of the nanocatalyst in real wastewaters, salty, and binary systems was acceptable and the pollutions were removed efficiently. The synergistic effect between V, Fe, and Ce could be account as the reason for the respectable function of FeVO4/CeO2. The electron transfer proceeds via Haber-Weiss mechanism. A degradation pathway was proposed through by-products analysis using gas chromatography-mass spectrometry (GC–MS) technique. The pseudo-first-order kinetic model described the obtained experimental results (R2 = 0.9906). The electro-Fenton system efficiency was improved by adding persulfate. The nanocomposite preserved almost its efficiency after six cycles. The obtained results demonstrate that the synergistic catalyst (FeVO4/CeO2) has the capability to introduce as a promising replacement of conventional catalysts in the electro-Fenton processes with brilliant proficiency.

A novel H2O2-persulfate hybrid system supported by electrochemically induced acidic and alkaline conditions for organic pollutant removal

Electro-Fenton (EF) and alkaline/persulfate systems are two important systems capable of producing ·OH and SO4−· for environmental remediation. However, the major drawbacks of these two processes are the necessity of operating in low pH (2.0–4.0) or high pH environments, where the acidification/alkalization steps and subsequent neutralization processes significantly increase the operation cost and limit their applicability. In this work, we propose a system that can simultaneously electrochemically develop acidic and alkaline environments in two divided compartments to solve this problem. pH values of 2.9–3.2 and 10.9–11.9 in two separated compartments were obtained, and the results show that the electrochemically developed acidic environment (pH of 3 and 4) enhances the EF process by facilitating H2O2 electrogeneration and Fe2+ regeneration. The alkaline environment (11 and 12) that was also developed electrochemically is effective for persulfate activation. Finally, the system was found to be effective for Rhodamine B removal using an acidic pH-enhanced EF process and an alkaline pH-supported persulfate process.

Technological Optimization for H2O2 Electrosynthesis and Economic Evaluation on Electro-Fenton for Treating Refractory Organic Wastewater

The current efficiency (CE) of electro-generation of H2O2 closely determines the cost of electro-Fenton process and is influenced by two aspects: intrinsic activity of catalysts and application par...

Real time monitoring of in situ generated hydrogen peroxide in electrochemical advanced oxidation reactors using an integrated Pt microelectrode

This work propose the fabrication and characterization of a Pt microelectrode integrated with a silver quasi-reference counter electrode (Pt/AgQRCE) for real time amperometric measurements of hydrogen peroxide electrochemically generated by water oxidation on Nb-supported boron doped diamond (Ni/BDD) anode. The developed electroanalytical method requires a very small sample volume and has higher sensitivity when compared to the conventional spectrophotometric analysis using ammonium metavanadate. The experiments were performed with Nb/BDD anode applying current densities of 30, 60, 90 and 120 mA cm−2 in 0.10 mol L−1 HClO4 supporting electrolyte showed that H2O2 production increase in the first 90 min of electrolysis and then reaches a plateau in both off-line and real time measurements. For the first 90 min, the electrogeneration of H2O2 exhibited a pseudo zero-order kinetics. The results obtained by the electrochemical amperometric analysis were compared to a spectrophotometric methodology reported on the literature and, at 95% confidence level the two methods do not demonstrated significant difference.