Chronoamperometric Measurements Research Articles

An Electrochemical Study with Three Redox Substances on a Carbon Based Nanogap Electrode Array

An Electrochemical Study with Three Redox Substances on a Carbon Based Nanogap Electrode Array

Mxene-Based Glucose Biosensor: Strong Dependence of Exfoliation Method on Performance

Over the last few years, the class of 2D materials has been expanded by a novel and uprising collection of early transition metal carbides known as MXenes. MXenes are synthesized via the selective etching of ‘A’ layers from their layered, ternary parent compounds, MAX phases, whereby M corresponds to early d-transition metal, A denoting a Group 13 or 14 main group sp-element, and X being either carbon or nitrogen. MXenes uniquely combine the metallic-like conductivity acquired from their parent counterparts, MAX phases and the hydrophilic nature of their surface terminating functional groups. The outstanding mechanical, chemical, physical and electrical properties of MXenes make them promising candidates for a myriad of applications, such as supercapacitors, catalysts and sensors. Inspired by the remarkable properties proffered by MXenes, we set forth to probe the feasibility of integrating MXene into a second-generation electrochemical glucose biosensor. Herein, MXenes were synthesized from their parent Ti3AlC2 MAX phase through two routes; (1) etching with 40% hydrofluoric acid (HF) (2) etching with 40% HF followed by subsequent delamination with 40% TBAOH, named Ti3C2-HF and Ti3C2-HF/TBA respectively. The heterogeneous electron transfer (HET) capabilities of these materials were examined and the superior material with the smallest peak-to-peak separation, pristine Ti3C2-HF/TBA, was then utilized to develop a glucose biosensor. Chronoamperometric measurements performed show that the proposed biosensing system displays high selectivity and remarkable electrocatalytic activity towards the detection of glucose. The glucose detection range spans over wide linear ranges of 50-27,750 µM and the proposed biosensor possesses a low limit of detection of 23.0 μM. The findings reported herein conceptually proves that pristine MXenes could be applied towards the development of biosensors and pave ways for future developments of highly selective and sensitive electrochemical biosensors for biomedical and food sampling applications.

Role of PCBM in the Suppression of Hysteresis in Perovskite Solar Cells

AbstractThe power conversion efficiency of inorganic–organic hybrid lead halide perovskite solar cells (PSCs) is approaching that of those made from single crystalline silicon; however, they still experience problems such as hysteresis and photo/electrical‐field‐induced degradation. Evidences consistently show that ionic migration is critical for these detrimental behaviors, but direct in‐situ studies are still lacking to elucidate the respective kinetics. Three different PSCs incorporating phenyl‐C61‐butyric acid methyl ester (PCBM) and a polymerized form (PPCBM) is fabricated to clarify the function of fullerenes towards ionic migration in perovskites: 1) single perovskite layer, 2) perovskite/PCBM bilayer, 3) perovskite/PPCBM bilayer, where the fullerene molecules are covalently linked to a polymer backbone impeding fullerene inter‐diffusion. By employing wide‐field photoluminescence imaging microscopy, the migration of iodine ions/vacancies under an external electrical field is studied. The polymerized PPCBM layer barely suppresses ionic migration, whereas PCBM readily does. Temperature‐dependent chronoamperometric measurements demonstrate the reduction of activation energy with the aid of PCBM and X‐ray photoemission spectroscopy (XPS) measurements show that PCBM molecules are viable to diffuse into the perovskite layer and passivate iodine related defects. This passivation significantly reduces iodine ions/vacancies, leading to a reduction of built‐in field modulation and interfacial barriers.

Ethanol Electrooxidation at Platinum-Rare Earth (RE = Ce, Sm, Ho, Dy) Binary Alloys

Proton exchange membrane fuel cells and direct alcohol fuel cells have been extensively studied over the last three decades or so. They have emerged as potential systems to power portable applications, providing clean energy, and offering good commercial viability. Ethanol is considered one of the most interesting fuels in this field. Herein, platinum-rare earth (Pt-RE) binary alloys (RE = Ce, Sm, Ho, Dy, nominal composition 50 at.% Pt) were produced and studied as anodes for ethanol oxidation reaction (EOR) in alkaline medium. A Pt-Dy alloy with nominal composition 40 at.% Pt was also tested. Their electrocatalytic performance was evaluated by voltammetric and chronoamperometric measurements in 2 M NaOH solution with different ethanol concentrations (0.2–0.8 M) in the 25–45 °C temperature range. Several EOR kinetic parameters were determined for the Pt-RE alloys, namely the charge transfer and diffusion coefficients, and the number of exchanged electrons. Charge transfer coefficients ranging from 0.60 to 0.69 and n values as high as 0.7 were obtained for the Pt0.5Sm0.5 electrode. The EOR reaction order at the Pt-RE alloys was found to vary between 0.4 and 0.9. The Pt-RE electrodes displayed superior performance for EOR than bare Pt, with Pt0.5Sm0.5 exhibiting the highest electrocatalytic activity. The improved electrocatalytic activity in all of the evaluated Pt-RE binary alloys suggests a strategy for the solution of the existing anode issues due to the structure-sensitive EOR.

Facile Synthesis and Electrochemical Performance of Graphene-Modified Cu2O Nanocomposite for Use in Enzyme-Free Glucose Biosensor

Graphene-modified Cu2O nanocomposite was synthesized under facile microwave irradiation of an aqueous solution and has been investigated as an enzyme-free glucose biosensor. Morphology and crystal structure of the graphene-modified Cu2O nanocomposite were investigated by using electron microscopy and X-Ray Diffraction (XRD) analyses. Also, the electrochemical performance of the graphene-modified Cu2O nanocomposite for the measurement of glucose concentration in alkaline media was evaluated by using cyclic voltammetry and chronoamperometric measurements. The electrochemical studies revealed that the graphene-modified nanocomposite electrode exhibited a high performance for non-enzymatic oxidation of glucose with a desirable sensitivity. Also, the fabricated graphene-modified biosensor exhibited a wide linear response for glucose detection in the concentrations ranges from 2 µM to 12 mM and a desirable detection limit of 2 µM. Also, the graphene-modified Cu2O nanocomposite provided an appropriate selective response for glucose detection in the presence of high concentrations of ascorbic acid and dopamine.

Ternary Pt/Re/SnO2/C catalyst for EOR: Electrocatalytic activity and durability enhancement

Carbon-supported Pt/C, Pt/Re/C, Pt/SnO2/C and Pt/Re/SnO2/C, with 20 wt.% overall metal loading were prepared and their electrochemical activity towards ethanol oxidation reaction (EOR) was investigated. Transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDS) revealed, that indeed binary and ternary combinations of the designed nanoparticles (NPs) were formed and successfully uniformly deposited on a carbon support. Fourier transform infrared spectroscopy (FTIR) allowed to assess the chemical composition of the nanocatalysts and X-ray diffraction (XRD) allowed to determine the catalyst structure. Potentiodynamic and chronoamperometric measurements were used to establish its catalytic activity and stability. The influence of Re addition on the electrochemical activity towards ethanol oxidation reaction (EOR) was verified. Indeed, the addition of Re to the binary Pt/SnO2/C catalyst leads to the formation of ternary Pt/Re/SnO2/C with physical contact between the individual NPs, enhancing the EOR. Furthermore, the onset potential of the synthesized ternary catalyst is shifted to more negative potentials and the current densities and specific activity are nearly 11 and 5 times higher, respectively, than for commercial Pt catalyst. Additionally ternary Pt/Re/SnO2/C catalyst retained 96% of its electrochemical surface area.

Effect of microstructure and internal stress on hydrogen absorption into Ni thin film electrodes during alkaline water electrolysis

Efforts to improve the cell efficiency of hydrogen production by water electrolysis continue to address the electrochemical kinetics of the oxygen and hydrogen evolution reactions in detail. The objective of this work is to study a parasitic reaction occurring during the hydrogen evolution reaction (HER), namely the absorption of hydrogen atoms into the bulk electrode. Effects of the electrode microstructure and internal stress on this reaction have been addressed as well in this paper. Ni thin film samples were deposited on a Si substrate by sputter deposition with different deposition pressures, resulting in different microstructures and varying levels of internal stress. These microstructures were first analyzed in detail by Transmission Electron Microscopy (TEM). Cathodic chrono-amperometric measurements and cyclic voltammetries have then been performed in a homemade electrochemical cell. These tests were coupled to a multi-beam optical sensor (MOS) in order to obtain in-situ curvature measurements during hydrogen absorption. Indeed, since hydrogen absorption in the thin film geometry results in a constrained volume expansion, internal stress generation during HER can be monitored by means of curvature measurements. Our results show that different levels of internal stress, grain size and twin boundary density can be obtained by varying the deposition parameters. From an electrochemical point of view, this paper highlights the fact that the electrochemical surface mechanisms during HER are the same for all the electrodes, regardless of their microstructure. However it is shown that the absolute amount of hydrogen being absorbed into the Ni thin films increases when the grain size is reduced, due to a higher grain boundaries density which are favourite absorption sites for hydrogen. At the same time, it was concluded that H2 evolution is favoured at electrodes having a more compressive (i.e. a less tensile) internal stress. Finally, the subtle effect of microstructure on the hydrogen absorption rate will be discussed as well.

Performance comparison with different methods for ethanol/O2 biofuel cell based on NAD+ cofactor immobilized and activated by two types of carbon nanoparticles

Biofuel cells are an attractive alternative to conventional fuel cells, because they use biological catalysts. We report in this article the construction of an ethanol/O2 enzymatic biofuel cell. In the first time, the performance comparison with different methods for ethanol/O2 biofuel cell has been study. Alcohol dehydrogenase, a nicotinamide adenine dinucleotide (NAD)-dependent enzyme, is immobilized with NAD+, diaphorase, and vitamin K3 (VK3) on the electrode. The oxygen is reduced at the cathode with laccase and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS). The performances of the electrodes are improved thanks to addition of carbon powder (KS6 and Super P® carbon). The benefit of the carbon particles with higher surface porosity was explained by the high-porous structure that offered a closer proximity to the reactive species and improved diffusion of ethanol and oxygen within the enzyme films. Efficiency of immobilization of NAD+ cofactor has been also demonstrated. We have shown the effect of multi-enzymatic reaction at the anode on the storage and operational stability. A high open-circuit potential has been recorded 1.02 V, demonstrating the benefit of NAD+ immobilization with maximal power density of 300 μW cm−2. Chronoamperometric measurements show a current density of 90 μA cm−2 during 20 h demonstrating the operational stability of the ethanol biofuel cell based on NAD+ cofactor immobilization.

Communication—Electrochemical Single Nano-Impacts of Electroactive Shewanella Oneidensis Bacteria onto Carbon Ultramicroelectrode

Electrochemical single nano-impacts of electroactive Shewanella oneidensis bacteria at a 7 μm diameter carbon fibre ultramicroelectrode in an aqueous potassium phosphate buffer (pH = 7.2) solution containing a redox active probe (potassium ferro- or ferricyanide) is reported. We present chronoamperometric measurements recorded at the ultramicroelectrode polarized at the potential of the steady-state current of the redox probe in solution (oxidation for K4Fe(CN)6 or reduction for K3Fe(CN)6) in the presence of bacteria. The shape of current transients associated to single bacteria nano-impacts is compared and discussed as a function of the redox probe in solution and of the ultramicroelectrode applied potential.

Intensifying Diffusion-Limited Reactions by Using Static Mixer Electrodes in a Novel Electrochemical Flow Cell

Surface-mediated reactions require effective mixing for them to be intense and efficient. In electrochemistry where the reactants must contact electrode surfaces for a sufficient time to enable electron tunnelling to occur, exhaustive electrolysis in poorly stirred reactors can take many hours to complete. As a consequence, electrochemical processing in many industries is restricted to batch processing which is more costly and labour intensive than continuous processing and results in significant down time between batches. This is not ideal for bulk production or treatment. Here we describe CSIRO’s novel axial flow electrochemical cell which aims to address these mixing problems by using a bespoke static mixer electrode (SME), designed by computational fluid dynamics (CFD) and manufactured using additive manufacturing (AM) technology to retain the fidelity of the original design. This electrode was characterized by SEM-EDS and electrosorption measurements. The performance of the electrochemical flow cell was evaluated by probing the ferricyanide ([Fe(CN)6]3−) reduction reaction on a platinum-coated SME under controlled mass transport conditions using cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometric measurements. This reaction was chosen because it has fast electron transfer kinetics, so the rate of reaction in dilute solutions is limited only by mass transport of the reactant to the electrode surface. Under the highest flow rate used (400 ml min−1) the cell enhanced the rate of reduction of ([Fe(CN)6]3− in a 10−3 M solution by 45 times compared with the no flow result. The impact the cell has diminishes as the concentration increases where mass transport plays a diminishing role in controlling the reaction rate. The performance of the cell is compared with a rotating disk electrode and a tubular flow cell and mass transfer coefficients are also presented for different reactant concentrations and flow conditions.

Platinum nanoparticles on defect-rich nitrogen-doped hollow carbon as an efficient electrocatalyst for hydrogen evolution reactions.

Design and synthesis of efficient electrocatalysts with low usage of precious metal and of high stability are essential for their practical applications in hydrogen evolution reactions. In this work, we synthesize an electrocatalyst through the deposition of platinum nanoparticles on defect-rich nitrogen-doped hollow carbon derived from surface-attached poly(4-vinylpyridine) monolayers. The platinum nanoparticles with an average diameter of about 1.8 nm are well dispersed on the outer surface of the pre-synthesized carbon material and the platinum loading is about 8.6 wt%. The mass activity of the as-synthesized catalyst under an overpotential of 55 mV is about 5.0 A mgPt−1, about 4.93 times higher than that of commercial Pt/C catalysts. Moreover, the synthesized catalyst is also more electrochemically stable than commercial Pt/C catalysts as evidenced by continuous cyclic voltammetry and chronoamperometric response measurements.

Engineering the Metal/Oxide Interface of Pd Nanowire@CuOx Electrocatalysts for Efficient Alcohol Oxidation Reaction.

The development of new type electrocatalysts with promising activity and antipoisoning ability is of great importance for electrocatalysis on alcohol oxidation. In this work, Pd nanowire (PdNW)/CuOx heterogeneous catalysts with different types of PdOCu interfaces (Pd/amorphous or crystalline CuOx ) are prepared via a two-step hydrothermal strategy followed by an air plasma treatment. Their interface-dependent performance on methanol and ethanol oxidation reaction (MOR and EOR) is clearly observed. The as-prepared PdNW/crystalline CuOx catalyst with 17.2 at% of Cu on the PdNW surface exhibits better MOR and EOR activity and stability, compared with that of PdNW/amorphous CuOx and pristine PdNW catalysts. Significantly, both the cycling tests and the chronoamperometric measurements reveal that the PdNW/crystalline CuOx catalyst yields excellent tolerance toward the possible intermediates including formaldehyde, formic acid, potassium carbonate, and carbon monoxide generated during the MOR process. The detailed analysis of their chemical state reveals that the enhanced activity and antipoison ability of the PdNW/crystalline CuOx catalyst originates from the electron-deficient Pdδ+ active sites which gradually turn into Pd5 O4 species during the MOR catalysis. The Pd5 O4 species can likely be stabilized by moderate crystalline CuOx decorated on the surface of PdNW due to the strong PdOCu interaction.

Oxygen Evolution Reaction on Single‐Walled Carbon Nanotubes Noncovalently Functionalized with Metal Phthalocyanines

AbstractThis work reports the facile preparation of single‐walled carbon nanotubes (SWCNTs) noncovalently functionalized with 3d transition metal (II) phthalocyanines MPcs (M=Mn, Fe, Co and Ni) and their electrochemical evaluation towards the oxygen evolution reaction (OER) in alkaline media. The modification of SWCNTs with MPcs improved the potential required for the oxygen evolution reaction in 0.1 M and 1 M KOH by lowering the potential by approximately 120 mV in comparison with unmodified SWCNTs, at a current density of 10 mA cm−1. The onset potential of the hybrids is close to the bulk Ni electrode in 1 M KOH and significantly outperforms Ni and Ir black electrodes in 0.1 M KOH solution. Nickel, cobalt and iron phthalocyanines showed auto‐activation during extended cyclic voltammetry and long‐term chronoamperometric measurements in both KOH concentrations. The excellent electrocatalytic activity of hybrids obtained and the straightforward method of their synthesis opens the possibility of exploring the proposed materials for applications in anion exchange membrane water electrolysis (AEMWE).

Synthesis of a Ni‐Pt Electrocatalyst Supported on PRh/ZnO Nanocomposites and Its Electrocatalytic Behaviour towards Methanol Electrooxidation

AbstractPolyrhodanine/Zinc Oxides (PRh/ZnO) nanocomposites were successfully synthesized through an in‐situ polymerization method. After that, the nanocomposites served as a substrate for bimetallic nickel‐platinum (Ni−Pt) to form PRh/ZnO/Ni/Pt electrocatalyst. Characterization methods including field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR) and x‐ray diffraction analysis (XRD) were then employed to investigate the morphology and chemical structure of synthesized samples. Next, the electrochemical activity of fabricated PRh/ZnO/Ni/Pt electrocatalyst in methanol electrooxidation reaction in alkaline media was investigated via cyclic voltammetry (CV) and chronoamperometric (CA) measurements. The experimental results indicated that the addition of Ni to the synthesized PRh/ZnO/Pt led to a higher electrochemically active surface area (EASA). Also, from the CV tests, a desirable amount of maximum anodic current density was achieved for the PRh/ZnO/Ni/Pt, which was as much as 35 mA cm−2. With regard to the density functional theory (DFT) calculations, computational results suggested that utilizing the PRh/ZnO structure beside Ni and Pt resulted in the improvement of the reactivity of catalyst and a decrease in the energy gap which was consistent with the experimental findings.

The investigation of electroreduction of [formula omitted] in the case of gold electrosorption using activated carbon

This paper reports a study of the kinetics of the initial stages of electroreduction of AuCl4- in the case of gold electrosorption using activated carbon. The activated carbon was synthesized from rice husk by the chemical activation. Obtained sorption materials were characterized by Raman Spectroscopy, Transmission electron microscopy, Scanning electron microscopy and SORBTOMETR-M techniques. The kinetics of electrodeposition of gold (III) on platinum from chloride electrolytes by the cyclic voltammetry and chronoamperometry methods have been studied. Chronoamperometric measurements were performed at the potential of +0.2 V vs. Ag/AgCl with varying gold concentration and temperature. Diffusion coefficient of Au3+ ions determined by the cyclic voltammetry method on the basis of the Randles-Ševčik equation is in good agreement with the value determined by the chronoamperometry using the Cottrell law.

Photocatalytic degradation kinetics of Orange G dye over ZnO and Ag/ZnO thin film catalysts

The degradation of water pollutants with photocatalysts is one of the most studied subjects in the past 20 years. Although considerable studies have been completed in this field, kinetic model studies are still a major inadequacy. In this study, ZnO and Ag/ZnO thin film photocatalysts were synthesized and SEM-EDS, XRD and chronoamperometric measurements were used the characterization of photocatalysts. The network kinetic model was applied the photocatalytic degradation of Orange G using ZnO and Ag/ZnO thin film photocatalysts. The photocatalytic degradation of Orange G was investigated under the different reaction medium (initial dye concentrations, temperature, light intensity). It was found that the network kinetic model is the most appropriate model for the degradation of Orange G dye on the ZnO and Ag/ZnO thin film photocatalysts. The calculated adsorption equilibrium (KB) constant and activation energy of ZnO thin film photocatalyst are 0.0191 and 21.76 kj/mol, respectively. Additionally, the calculated values for Ag/ZnO thin film photocatalyst are 0.035 and 18.32 kj/mol. The general rate equations were determined for each photocatalysts.

Optimizing the activity and selectivity of glycerol oxidation over core-shell electrocatalysts

High-performance electrocatalysts with excellent activity and selectivity hold the key to the electrochemical conversion of glycerol. Herein, well-defined bimetallic Au@Ag and trimetallic PdAu@Ag core-shelled nanoparticles were fabricated using a seed-mediated growth process and further examined as electrocatalysts for glycerol oxidation in both alkaline and acidic solutions. The activity of the catalysts was evaluated via cyclic voltammetry, linear sweep voltammetry and chronoamperometric measurements. The Au@Ag and PdAu@Ag nanoparticles are highly active in alkaline solutions, but inactive in acidic solutions. In alkaline solutions, the PdAu@Ag and Au@Ag nanoparticles show current densities of 3.94 and 2.57 mA cm−2, which are 4.3 and 25.7 times those of the commercial Pd/C and Au/C catalysts, respectively. The products of glycerol electro-oxidation were analyzed by high performance liquid chromatography (HPLC). Three major products, namely dihydroxyacetone (DHA), glyceric acid, glyceraldehyde and five minor products including oxalate acid, tartronic acid, formic acid, glycolic acid (GA) and glyoxylic acid were detected. Notably, a remarkable DHA selectivity of 70.1% was obtained from the PdAu@Ag catalyst at 0.9 V. The Au@Ag yields the largest GA selectivity of 31.6% at 1.1 V. The PdAu@Ag tends to yield more C3 products at high applied potentials.

Influence of surface characteristics on the penetration rate of electrolytes into model cells for lithium ion batteries

Filling of cells with liquid electrolytes is the time-determining step in the production of lithium-ion batteries (LIBs). The influencing factors are not completely understood and need further research. The adhesion of the solid components, i.e. anode, cathode and separators, to the electrolyte and the respective interfaces play an important role. In this study, the penetration of liquid electrolytes is monitored by a combination of tensiometry and chronoamperometry. A setup including all battery components is proposed as model for battery cells. Diethyl carbonate is employed as model for the electrolyte. The penetration rates of the liquid into a stepwise extended model setup (separator; anode; cathode; separator/anode; separator/cathode; and anode/separator/cathode) in confined geometry between glass plates are determined with reproducible results. A modified Washburn equation combining surface tensions of liquid and solids forming the interface, and complex geometries of separators and electrodes is used to develop the penetration model. Comparative measurements in a glove box yield comparable results with the real electrolyte solution. The penetration of the model electrolyte into ceramic-coated separators is significantly faster than into polyolefin separators due to higher surface roughness and higher polarity of ceramic-coated separators. The wetting times obtained by chronoamperometric measurements correlate with the tensiometric penetration rates. The higher the tensiometric penetration rate, the lower is the chronoamperometric wetting time. The results of the study contribute to a deeper understanding of the interactions between electrolyte and solid components in LIBs and provide a new method to pre-evaluate battery components.

Nanoporous Cu2O nanotube/nanorod array electrodes for non-enzymatic glucose sensing with high sensitivity and very low detection limit

This study compares the non-enzymatic glucose sensing performance by Cu2O nanorods/nanotubes grown using electrochemically anodized Cu foam and Cu plates to form binder free one-dimensional Cu(OH)2 nanostructures which were subsequently annealed at higher temperatures. Resulting Cu2O nanorods/nanotubes had diameters between 100 and 200 nm and lengths in excess of 10 μm. The surface morphology and structure of these thin films studied using scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy showed that the copper foam based Cu2O structures consisted of nanotubes/nanorods distributed over entire 3-dimensional space containing dense nano-pores of size ∼20 nm on outer surfaces. Cu plate based nanorods consisted of grooved macaroni type surface morphologies. Non-enzymatic glucose sensing made using chronoamperometric and cyclic voltammetric measurements showed that the Cu2O/Cu foam electrodes had a high sensitivity of 5792.7 μA mM−1 cm−2, a very low detection limit of 15 nM (S/N = 3), multi-linear detection ranges of 15 nM–0.1 μM and 575–4098.9 μM with a faster response time of less than 1 s. Cu plate based nanorods showed a sensitivity of 141.9 μA mM−1 cm−2, with a lower detection limit of 510 nM (S/N = 3). The significantly high sensitivity of Cu2O/Cu foam electrodes is attributed to the availability of increased amount of active sites due to the large effective surface area provided by Cu2O nanorods/nanotubes. The study also demonstrates the influence of the substrate on surface morphology of the nanorods/nanotubes. These Cu foam based Cu2O electrodes provide a promising platform for non-enzymatic glucose detection with high specificity and reproducibility.

Comparative study of electrochemical Corrosion of Novel Designs of 90/10 and 70/30 Copper-Nickel Alloys in Brine Solutions

Copper-nickel alloy is a material of choice for condensers and heat exchangers, where seawater is used as a coolant and in desalination plants. In this work, we survey the comparative corroding behavior of novel designs of 90/10 and 70/30 Copper-Nickel alloys under higher salinity (3.5 wt%, 10 wt% and 15 wt% NaCl). The electrochemical corrosion of Cu-Ni alloys in brine solutions was studied using potentiodynamic polarization, chronoamperometric and electrochemical impedance spectroscopy measurements along with scanning electron microscope (SEM) and energy dispersive X-Ray analyzer (EDX) investigations. Polarization data showed that Cu-10 Ni alloy is more corrosive than Cu-30 Ni alloy in 3.5 wt% NaCl solutions. Chronoamperometric curves confirmed the results obtained by polarization measurements that the uniform and pitting corrosion of Cu-Ni alloy were reduced in the Cu-30 Ni alloy in 3.5wt% NaCl solutions. Impedance spectra revealed that the surface and polarization resistances recorded higher values in Cu-30Ni alloy. SEM/EDX investigations indicated that the corrosion of Cu-Ni alloys proceeded by the selective electro-dissolution of nickel, which allowed copper enrichment on the surface of the alloy. The heat exchanger served to heat desalinated water, the water had a high chloride level. Corrosion examination indicated susceptibility towards pitting corrosion, especially at high temperature.