Chronoamperometric Experiments Research Articles

2D Bi2WO6/MoS2 as a new photo-activated carrier for boosting electrocatalytic methanol oxidation with visible light illumination

ABSTRACT In this paper, a new two-dimensional (2D)/2D composite of Bi2WO6/MoS2 was facile synthesized, and then was used as supporting material for depositing Pt nanoparticles. The as-synthesized Pt-Bi2WO6/MoS2 was extended into photo-assisted electrocatalytic oxidation of methanol, which is a model anode reaction for direct methanol fuel cell. Compare with traditional electrocatalytic process, Pt-Bi2WO6/MoS2 displays 1.5 times enhanced electrocatalytic performance on methanol oxidation with assistance of visible light irradiation and 2.2 times for commercial Pt/C. Besides, from the results of chronoamperometric and chronopotentiometry experiments, the stability of Pt-Bi2WO6/MoS2 electrode is clearly improved under visible light irradiation. The synergistic effects of photo- and electro-catalytic in the heterojunction of Pt-Bi2WO6/MoS2 in favor of the above enhancement. This research gives more insights in the fields of photo-assisted traditional electrocatalytic application by constructing of semiconductor heterojunction carrier.

One-step preparation of silver electrodeposits from non-aqueous solvents

http://172.20.145.48/elsevier_cbt/wp-login.php?loggedout=trueThis paper describes the Ag electrodeposition on platinum electrode in different deep eutectic solvents (DES) as electrolytes, such as choline chloride:ethylene glycol (ChCl:EG) and choline chloride:urea (ChCl:U), using a molar ratio of 1:2. Having a concentration of 0.05 mol L−1 of silver nitrate in each DES, the electrodeposition was studied using cyclic voltammetry (CV), which shown a sole reduction and oxidation processes. The electrodeposition temperature was also studied in both solvents, having the Ag+ ions reduction peak potential shifted to relative lesser negative values and the reduction peak current relatively increased if compared with room temperature (RT) voltammograms. Using the optimized voltammetric conditions of Ag electrodeposition, the cathodic yield reached >80% in all studied temperatures and DES solutions. Chronoamperometric experiments were conducted in order to achieve Cottrell plots for determination of Ag+ ions diffusion coefficient (Do) for all DES electrolytes and temperatures, and its magnitude order was around 10−7 cm s−1 due to viscosity of the DES. In order to study the Ag nucleation mechanism in both DES electrolytes, dimensionless Scharifker-Hills (SH) model was applied. The analysis showed that Ag electrocrystallization in ChCl:EG had an intermediate mechanism at 25 °C and 45 °C, while 70 °C presented an instantaneous behavior, and Ag electrodeposition in ChCl:U showed progressive electrocrystallization in 25 °C and instantaneous behavior at 45 °C and 70 °C. SEM images showed a distribution of sub-micrometer Ag particles over bulk Ag electrodeposit, suggesting that Ag+ ions deposition using ChCl:EG and ChCl:U DES as electrolytes can achieve electrochemical synthesis of Ag microparticles.

Macroporous composite capacitive bioanode applied in microbial fuel cells

Interfacial electron transfer between electroactive biofilm and the electrode was crucial step for microbial fuel cells (MFCs). A three-dimensional multilayer porous sponge coating with nitrogen-doped carbon nanotube/polyaniline/manganese dioxide (S/N-CNT/PANI/mnO2) electrode has been developed for MFC anode. Here, the S/N-CNT/PANI/MnO2 anode can function as a biocapacitor, able to store electrons generated from the degradation of organic substrate under the open circuit state and release the accumulated electrons upon requirement. Thus, the mismatching of the production and demand of the electricity can be overcome. Comparing with the sponge/nitrogen-doped carbon nanotube (S/N-CNT) bioanode, S/N-CNT/PANI/MnO2 capacitive bioanode displays a strong interaction with the microbial biofilm, advancing the electron transfer from exoelectrogens to the bioanode. The maximum power density of MFC with S/N-CNT/PANI/MnO2 capacitive bioanode is 1019.5 mW/m2, which is 2.2 and 5.8 times as much as that of S/N-CNT/MnO2 bioanode and S/N-CNT bioanode (470.7 mW/m2 and 176.6 mW/m2), respectively. During the chronoamperometric experiment with 60 min of charging and 20 min of discharging, the S/N-CNT/PANI/MnO2 capacitive bioanode was able to store 10743.9 C/m2, whereas the S/N-CNT anode was only able to store 3323.4 C/m2. With a capacitive bioanode, it is possible to use the MFC simultaneously for production and storage of electricity

A 3D porous NCNT sponge anode modified with chitosan and Polyaniline for high-performance microbial fuel cell

A microbial fuel cell (MFC) is a potential bio-electrochemical technology that utilizes microorganisms to convert chemical energy into electrical energy. The low power output of MFCs remain the bottleneck for their practical applications. In this paper, a novel, biocompatible and bioelectrocatalytic composite chitosan-nitrogen doped carbon nanotubes-polyaniline (CS-NCNT-PANI) was prepared in situ on the 3D porous NCNT/sponge and applied to an MFC anode. The PANI was grafted on the CS-NCNT backbone to synthesize the ternary composite. This bioanode not only increased the active surface area and capacity but also facilitated bacterial adhesion and enrichment of microbes. Compared with the NCNT/sponge electrode, the charge transfer impedance of the ternary composite bioanode decreased from 14.07 Ω to 2.25 Ω, and the maximum power density increased from 1.4 W·m−3 to 4.2 W·m−3; meanwhile, during the chronoamperometric experiment with a charge-discharge time of 60–60 min, the cumulative charge of the composite bioanode was 18,865.8 C·m−2, which is much higher than that of the NCNT/S anode (3625.3 C·m−2). High-throughput sequencing technology revealed that the ternary composite bioanode had good biocompatibility and high diversity. Therefore, this synthesized ternary composite is a promising candidate as a capacitive and biocompatible anode material in MFC.

Electrochemical Ammonia Generation Directly from Nitrogen and Air Using an Iron-Oxide/Titania-Based Catalyst at Ambient Conditions.

Ammonia was produced electrochemically from nitrogen/air in aqueous alkaline electrolytes by using a Fe2O3/TiO2 composite catalyst under room temperature and atmospheric pressure. At an applied potential of 0.023 V versus reversible hydrogen electrode, the rate of ammonia formation was 1.25 × 10-8 mmol mg-1 s-1 at an overpotential of just 34 mV. This rate increased to 2.7 × 10-7 mmol mg-1 s-1 at -0.577 V. The chronoamperometric experiments on Fe2O3/TiO2/C clearly confirmed that Fe2O3 along with TiO2 shows superior nitrogen reduction reaction activity compared to Fe2O3 alone. Experimental parameters such as temperature and applied potential have a significant influence on the rate of ammonia formation. The activation energy of nitrogen reduction on the employed catalyst was found to be 25.8 kJ mol-1. Real-time direct electrochemical mass spectrometry analysis was used to monitor the composition of the evolved gases at different electrode potentials.

Polyethyleneimine/Graphene Multilayer Film Supported Ferric Cobalt Modified Electrode for High-Performance Sensing of L-cysteine

One novel chemically modified electrode (CME) was prepared through fabricating polyethyleneimine/oxidized graphene multilayers on indium tin oxide (ITO) slide via layer-by-layer assembly followed by electrochemically depositing cobalt hexacyanoferrate. A large range of methods were used to characterize the morphology and electrochemical properties of the electrode including field-emission scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, cyclic voltammetry, differential pulse voltammetry (DPV), electrochemical impedance spectroscopy and chronoamperometry. Under optimized conditions, the oxidation current of DPV (typically at 0.2 V vs. saturated calomel electrode) increased linearly in the range of 5 × 10−5 to 2 × 10−3 mol L−1. And the limit of detection and the limit of quantity were 4.6 × 10−7 mol L−1 and 1.5 × 10−6 mol L−1 (based on signal-to-noise ratio of 3 and 10), respectively. Average recoveries from (spiked) commercial mask were between 98.1% and 104.5% with relative standard derivations less than 3.14% (n = 3) at three spiked levels. The method was validated by HPLC. Furthermore, the possible mechanism of L-Cys detection was studied based on chronoamperometric experiments.

Correlating the Short-Time Current Response of a Hydrogen Evolving Nickel Electrode to Bubble Growth

Gas evolving electrochemical reactions induce bubble formation and growth at surfaces of electrodes. To study one such situation, hydrogen evolution on nickel electrodes, short time chronoamperometric experiments were performed in combination with in-situ microscopy. The entire electrode of 3.14 mm2 was imaged with confocal microscopy and the current response of the electrode then correlated to the observed bubble growth features. Somehow counterintuitively, first a 2–3% increase in current was observed consistently when a bubble grows close to the electrode on the edge of the electrode holder, made of a polymer. This is argued to be due to the removal of surface attached gas from the electrode. Next, we observe a consecutive regime of decreasing current, in which large bubbles accumulate on the surface. Interestingly, when these surface attached bubbles coalesce, a steep change in current is observed, which is accompanied by a burst of small bubbles nucleating on the surface previously occupied by the large bubble. These phenomena are qualitatively discussed on the basis of existing literature, and implications for improvements for electrodes on which gases are produced, are outlined.

Synthesis and characterization of n-ZnO/p-MnO nanocomposites for the photocatalytic degradation of anthracene

n-ZnO/p-MnO nanocomposites with different percentages of manganese (0.5%, 1.1%, and 2.25%) with a semiconducting junction were prepared. Changes in Flat band potential (Efb) for ZnO due the different amounts of MnO was observed, meanwhile same donor density (Nd) was held in all materials. From chronoamperometric experiments under on-off illuminated conditions a transient time constant (τ), related to the electron transport in the electrodes were calculated, where higher values are observed in materials with high amounts of MnO. Photodegradation studies of anthracene in an ethanol:water (1:1, pH 12) solution were performed, showing that anthraquinone is the main product with no photodegrading of ethanol. The results suggest that the junction n-ZnO/p-MnO and materials with high transient time constant (τ), enhance the photocatalytic degradation. The best photocatalytic performance for the photodegradation of anthracene was obtained with the nanocomposite n-ZnO /p-MnO(Mn=2.25%).

Electrochemical reduction of graphene oxide on biomedical grade CoCr alloy

In the present work, the characterization of Electrochemically Reduced Graphene Oxide (ErGO) films on a biomedical grade CoCr alloy has been performed. The direct electrodeposition process was carried out by means of two electrochemical techniques: chronoamperometry and cyclic voltammetry experiments, both taking into account the influence of oxygen in the solution. Characterization of the resulting ErGO films on CoCr alloys was carried out by SEM, AFM, Raman spectroscopy and XPS. Both electrochemical reduction procedures led to the deposition of graphene-based films on the CoCr surfaces after the partial removal of the oxygenated functional groups present in the graphene network of the starting material. The deconvolution of the XPS high-resolution C1s and O1s spectra mainly showed Csp2 bonding and the presence of CO and CO residual groups covering the CoCr surface. Moreover, the ErGO films that were stacked on the CoCr surfaces exhibited non-uniform thickness reaching values corresponding to the presence of 80 layers of the graphene material. In addition, Raman spectroscopy revealed a certain structural disorder in the ErGO films deposited by means of the different electrochemical techniques investigated. This fact was more evident on the film from the chronoamperometric experiments, as the fastest electrochemical reduction rate provided by the application of a high reduction potential (−2.1 Vvs. Ag/AgCl) could induce the development of defects in the resulting film, so the peaks corresponding to the CoCr substrate could be observed.

Direct current electrodeposition of Co-ITO nanoflakes modified steel electrode for highly selective non enzymatic detection of catechol

Dihydroxy benzenes are considered as toxic pollutants that had harmful impact on environment. The present study is focused on the fabrication of an electrochemical sensor based on Co-ITO nanoflakes electrode on mild steel surface for highly sensitive and selective detection of catechol, prepared using simple electrodeposition route without any binders. The surface morphology, elemental composition and the crystal structure were confirmed from SEM, EDX XPS and XRD analyses respectively. The electrochemical characterization was done using cyclic voltammetry and chronoamperometric techniques. The electrocatalytic oxidation of catechol at Co and Co-ITO modified electrode was studied in 0.1 M NaOH vs Ag/AgCl at 50 mVs−1 scan rate. When catechol was added, the anodic oxidation peaks got increased with the decrease in the cathodic reduction current which revealed the electrocatalytic activity of Co-ITO nanoflakes electrode. Chronoamperometric experiments were performed to get the linear range, sensitivity and detection limit. For each and every addition of catechol, a stepwise increment of current was observed. The interference test and real sample analysis were also performed which revealed good selectivity and recovery. The above results demonstrated that Co-ITO nanoflakes electrode could be a promising electrode for catechol sensing in real situations.

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.

Carbon-supported iron complexes as electrocatalysts for the cogeneration of hydroxylamine and electricity in a NO-H2 fuel cell: A combined electrochemical and density functional theory study

Carbon-supported iron complexes were investigated as electrocatalysts for the reduction of nitric oxide (NO) in a H2-NO fuel cell conceived for the production of hydroxylamine (NH2OH) with concomitant generation of electricity. Two types of iron complexes with tetradentate ligands, namely bis(salicylidene)ethylenediimine (Salen) and phthalocyanine (Pc), supported on activated carbon or graphite were prepared and evaluated as electrocatalysts, either without further treatment or after pyrolysis at 700 °C. The performance in the reduction of NO of gas diffusion cathodes based on these electrocatalysts was investigated in an electrochemical half cell (3-electrode configuration) using linear sweep voltammetry (LSV). The most promising electrocatalysts were studied further by chronoamperometric experiments in a H2-NO fuel cell, which allowed comparison in terms of power output and hydroxylamine production. Depending on the concentration of the NO feed (6 or 18%), the best electrocatalytic performance was delivered either by FePc or FeSalen. The gas diffusion electrode based on FeSalen supported on activated carbon with 0.3 wt% Fe-loading provided the highest current density (86 A/m2) and the best current efficiency (43%) towards the desired NH2OH when operating at the higher NO concentration (18%). Moreover, FeSalen offers the advantage of being cheaper than FePc. The experimental work was complemented by density functional theory (DFT) calculations, which allowed to shed more light on the reaction mechanism for the reduction of nitric oxide at the atomistic level.

An enhanced Nonenzymatic Electrochemical Glucose Sensor Based on Copper‐Palladium Nanoparticles Modified Glassy Carbon Electrodes

AbstractNovel copper‐palladium nanoparticles modified glassy carbon electrodes (Cu−Pd/GC) with enhanced nonenzymatic sensing for glucose were facilely prepared by one‐step electrodeposition. The structure and composition of the prepared nanoparticles were characterized by XRD, SEM, TEM and EDS, respectively. The electrode modified process was characterized by electrochemical impedance spectroscopy. Cyclic voltammetry and chronoamperometric experiments were used to evaluate the electrocatalytic activities of the electrodes toward glucose. The surface morphology and the electrocatalytic activities of Cu−Pd/GC was compared to Pd and Cu nanoparticles modified glassy carbon electrodes (Pd/GC and Cu/GC), respectively. Thanks to homogeneous distribution of Cu−Pd nanoparticles and the synergistic effect of Cu and Pd atoms, Cu−Pd/GC exhibited the highest sensitivity (298 μA mM−1 cm−2) and the widest linear amperometric response (0.01 mM to 9.6 mM, R2=0.996) toward glucose compared to Pd/GC and Cu/GC. The detection limit of Cu−Pd/GC was 0.32 μM (S/N=3). In addition, the as‐prepared Cu−Pd/GC glucose sensor also exhibited exceptional capabilities of anti‐interference, reproducibility and long‐term stability. The as‐prepared sensor was also evaluated for determination of glucose concentration in human blood serum samples, which exhibited high reliability and accuracy, having great potential in clinical application.

Prediction of Ce(III) Electrodeposition at Various Electrochemical Conditions in Molten LiCl-KCl Eutectic

In this work, the empirical correlation formula for the prediction of electrodeposition of Ce(III) was derived. The formula includes variables of reaction time, current, and concentration, which are controllable variables during the experiment. Deriving this formula enabled a preliminary prediction of the amount of deposits with three known variables under assumption of no physical detachment or loss of deposits during the experiment. The boundary condition of concentration in the formula was defined as 0.48 wt.% < c < 1.10 wt.%. The formula was validated through a direct application to actual experiments, and the relative errors in prediction were close to or less than 10 % up to the reaction time of 400 seconds. A relatively larger error was caused in longer electrodeposition because of the randomness in the growth of deposits. Furthermore, three different characteristics of electrodeposition (mild, intermediate, and mossy) were verified through multiple chronoamperometric experiments at various concentrations.

Facile Electrodeposition of Hierarchical Co‐Gd2O3 Nanocomposites for Highly Selective and Sensitive Electrochemical Sensing of L–Cysteine

AbstractMetal/metaloxide based composite materials have wide spread applications in electrochemical sensors and fuel cell applications. Hence, the present work is directed towards the fabrication of cost effective and highly sensitive electrode material for cysteine sensing. In this work, Co‐Gd2O3 nanocomposite is prepared by a simple electrodeposition route and used as electrochemical sensor material. The prepared nanocomposite materials are characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X‐ray Diffraction spectroscopy (XRD), Energy dispersive X‐ray spectroscopy (EDX), and X‐ray Photo electron spectroscopy (XPS). SEM images exhibited as hierarchical nanoflakes with open porous structure. EDX analysis showed the presence of cobalt and gadolinium. The reflections at 2θ=330 and 35.70 corresponds to the cubic structured Gd2O3 nanoparticles validated the formation of nanocomposite. Electrooxidation of L‐cysteine on Co and Co‐Gd2O3 was carried out using cyclic voltammetry technique. Upon addition of certain concentration of cysteine, the anodic peak current get increased with the simultaneous decline in the cathodic peak currents displayed the excellent electrocatalytic activity of Co‐Gd2O3 nanocomposite. The chronoamperometric experiments were performed to derive the analytical parameters like sensitivity, limit of detection and linear range. The reproducibility, stability and real sample analysis was studied using chronoamperometry.

Trace Element Removal in Distributed Drinking Water Treatment Systems by Cathodic H2O2 Production and UV Photolysis.

As water scarcity intensifies, point-of-use and point-of-entry treatment may provide a means of exploiting locally available water resources that are currently considered to be unsafe for human consumption. Among the different classes of drinking water contaminants, toxic trace elements (e.g., arsenic and lead) pose substantial operational challenges for distributed drinking water treatment systems. Removal of toxic trace elements via adsorption onto iron oxides is an inexpensive and robust treatment method; however, the presence of metal-complexing ligands associated with natural organic matter (NOM) often prevents the formation of iron precipitates at the relatively low concentrations of dissolved iron typically present in natural water sources, thereby requiring the addition of iron which complicates the treatment process and results in a need to dispose of relatively large amounts of accumulated solids. A point-of-use treatment device consisting of a cathodic cell that produced hydrogen peroxide (H2O2) followed by an ultraviolet (UV) irradiation chamber was used to decrease colloid stabilization and metal-complexing capacity of NOM present in groundwater. Exposure to UV light altered NOM, converting ∼6 μM of iron oxides into settable forms that removed between 0.5 and 1 μM of arsenic (As), lead (Pb), and copper (Cu) from solution via adsorption. After treatment, changes in NOM consistent with the loss of iron-complexing carboxylate ligands were observed, including decreases in UV absorbance and shifts in the molecular composition of NOM to higher H/C and lower O/C ratios. Chronoamperometric experiments conducted in synthetic groundwater revealed that the presence of Ca2+ and Mg2+ inhibited intramolecular charge-transfer within photoexcited NOM, leading to substantially increased removal of iron and trace elements.

Microbial fuel cells: enhancement with a polyaniline/carbon felt capacitive bioanode and reduction of Cr(VI) using the intermittent operation

With the increasing concern for energy sources, waste management, the search for novel technological solutions continues. Microbial fuel cell is a new biotechnology that utilizes bacteria as catalysts to decompose organic substrate and simultaneously harvest electricity. Anodes play an important role in deciding the microbial fuel cell. In this paper, the cumulative charge of the polyaniline-modified bioanode from the chronoamperometric experiment with 20 min of charging and 20 min of discharging is 13,930.1 C m−2, much higher than that of bare carbon felt anode (5908.1 C m−2). Then, we investigated two different operations of the microbial fuel cell (intermittent and continuous operations) to remove Cr(VI) in the cathode chamber. Under intermittent operation, 71.1% of Cr(VI) was reduced, which was 1.13-fold greater than under continuous operation. This study suggested that the microbial fuel cell anode containing polyaniline pseudo-capacitive materials has the potential for storing energy from wastewater and releasing the energy in a short time to an electronic device. These favorable Cr(VI) removal results contribute to the capacitive anode in the charging process of intermittent operation, produce and store electricity simultaneously, and release a greater portion of the electricity stored in the anode than under continuous operation in the process of degradation, thereby gaining a larger current. Here we show that a microbial fuel cell containing a pseudo-capacitive material, such as polyaniline, functions as a biocapacitor, stores bioelectrons generated from microbial oxidation of substrate, and releases the accumulated charge simultaneously.

Electrochemical Faradaic Spectroscopy

AbstractFor the purpose of simplification of the electrochemical study under conditions of square‐wave voltammetry (SWV), a simplified form of potential modulation is proposed by replacing the staircase potential ramp with a constant potential. The resulting potential modulation, which could be considered as a pulse form of a chronoamperometric experiment (i. e., square‐wave chronoamperometry), is provisionally termed as electrochemical faradaic spectroscopy, considering the fact that the main tool in the kinetic analysis is the frequency of the potential pulses applied. The proposed technique is illustrated with theoretical analysis of a simple, kinetically controlled electrode reaction of a dissolved redox couple and experimentally verified with the Eu3+(aq)/Eu2+(aq) redox couple at a mercury electrode. The square‐wave chronoamperometry exhibits unique features of the response absent in both conventional SWV and chronoamperometry, widening the range of accessible electrode kinetics.

Flexible Electrochemical Biochip Array of Patterned Gold on Silver Inkjet Printed Polyimide

Flexible electrodes for bio-electrochemical sensing were fabricated using state-of-the-art inkjet printing followed by two consecutive gold plating steps. Silver nanoparticle printed thin film (1.5μm thick) was sintered at 300°C for 30 minutes and used as seed for the electroless plating of gold (2μm). A further gold electroplating layer was then applied allowing good electrode properties overcoming the printed film roughness and porous morphology which the electroless plating step could not fully cover. The various layers as well as their composite were investigated using electrical, electrochemical and analytical techniques. Eventually, the final electrode was tested with a 3-electrodes setup in a chronoamperometric experiment to detect the Alkaline Phosphatase enzyme in presence of its substrate, ρ-Aminophenyl Phosphate. The electrodes demonstrated a sensitivity of 11.8μA/mM and a limit of detection of 0.9mM.

Sustainable Non-Noble Metal Bifunctional Catalyst for Oxygen-Depolarized Cathode and Cl2 Evolution in HCl Electrolysis

The composite of polyoxometalate [WZn3(H2O)2(ZnW9O34)2]12– (ZnPOM) with polyvinylidene-butyl-imidazolium cation (PVIM) and oxidized carbon nanotubes (OCNT) as non-noble metal bifunctional catalyst has been studied for oxygen-depolarized cathode (ODC) and Cl2 evolution in HCl electrolysis for the first time. The cyclic voltammetry and rotating disk electrode measurement analysis reveals superior activity of the composite as bifunctional catalyst for ODC and Cl2 evolution. Chronoamperometric experiments show high long-term stability, comparable to the state-of-art catalyst, even under multiple shutdown to open circuit potential. X-ray photoelectron spectroscopic studies after electrolysis (48 h) confirms no degradation of the composite and, hence, appears to be stable. Scanning electrochemical microscopy (SECM) measurements indicate that, even after 72 h of electrolysis, the composite retains high activity, similar to fresh composite.