Copper Electrode Surface Research Articles

Electroanalytical analysis of phenol oxidation using bacteria immobilized by a polycaprolactone coating on the copper electrode surface

The copper electrode modified by bacteria immobilised by a polycaprolactone film was successfully developed by electropolymerisation for the purpose of determining the presence of phenol. Electrochemical techniques such as square-wave voltammetry (SWV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the electrochemical properties of the Cu-polymer/bacteria electrode. The results show that the intensity of the phenol oxidation peak increases with concentration, allowing us to obtain good analytical results with DL of 2.156 × 10–7 M and QL which is 7.2 × 10–7 M , confirming that the biosensor has excellent electroanalytical activity for phenol oxidation, with good stability and a wide linear range. Our electrode is based on a easily available and inexpensive material, as well as on its simple preparation, which has demonstrated high performance for phenol.

Formation of field-induced breakdown precursors on metallic electrode surfaces

Understanding the underlying factors responsible for higher-than-anticipated local field enhancements required to trigger vacuum breakdown on pristine metal surfaces is crucial for the development of devices capable of withstanding intense operational fields. In this study, we investigate the behavior of nominally flat copper electrode surfaces exposed to electric fields of hundreds of MV/m. Our novel approach considers curvature-driven diffusion processes to elucidate the formation of sharp breakdown precursors. To do so, we develop a mesoscale finite element model that accounts for driving forces arising from both electrostatic and surface-tension-induced contributions to the free energy. Our findings reveal a dual influence: surface tension tends to mitigate local curvature, while the electric field drives mass transport toward regions of high local field density. This phenomenon can trigger the growth of sharper protrusions, ultimately leading to a rapid enhancement of local fields and, consequently, to a runaway growth instability. We delineate supercritical and subcritical regimes across a range of initial surface roughness. Our numerical results are in qualitative agreement with experimentally reported data, indicating the potential practical relevance of field-driven diffusion in the formation of breakdown precursors.

Surface-Reconstructed Copper Foil Free-Standing Electrode with Nanoflower Cu/Ce2O3 by In Situ Electrodeposition Reduction for Electrocatalytic Nitrate Reduction to Ammonia.

The electrocatalytic reduction of nitrate to ammonia (NRA) is considered to be a promising and environmentally friendly alternative to the Haber-Bosch process. Herein, a simple in situ electrodeposition-reduction method is proposed, which allows for the surface reconstruction and modification of copper foil by introducing cerium. The surface modification results in the formation of Cu/Ce2O3 nanoflowers on the copper electrode surface. Additionally, density functional theory calculations demonstrate that Ce2O3 enhances the adsorption of NO3-. Compared with a pure copper electrode, the NRA performance of surface-reconstructed copper is greatly improved, with the maximum ammonia yield rate and the highest Faradaic efficiency from 24.8% to 73.0% and from 0.081 to 0.386 mmol h-1 cm-2, respectively. The 15N isotope labeling experiment confirms that the nitrogen source in the ammonia originated from nitrate.

Influence of Laser Wavelength in Simultaneous Patterning of Fluorinated Ethylene Propylene and Copper Electrode Surface Towards Performance Enhancement of Triboelectric Nanogenerator

Triboelectric nanogenerators (TENGs) are promising cost‐effective energy harvesters useful to scavenge vibration or mechanical movements from various domains. Ranging from condition monitoring of machines to motion sensing of humans, its applications are enormous in the internet of things scenario. Enhancing the performance of small‐sized TENGs is of great demand, and pulsed laser‐assisted texturing is an efficient and proven method to enhance the output of energy harvesters. This work studies simultaneous laser patterning of fluorinated ethylene propylene (FEP) dielectric material and the underneath copper electrode with three different wavelengths (355, 532, and 1064 nm) of the Nd3+:YAG laser and the device's electrical performance is analyzed. The maximum enhancement is observed in the case of 355 nm laser‐assisted patterning on FEP and Cu electrode with a laser fluence of 10 J cm−2. The improvement is least in the case of 1064 nm laser‐assisted patterning. Laser patterning on the underlying electrode with this new approach is able to produce an enhancement in the TENG output. However, patterning on the FEP top surface is critical in the process.

Revealing pre-breakdown processes of a single-gap pseudospark switch triggered from the anode side

Pseudospark switch is a special kind of low-pressure (typically 1–100 Pa) high-voltage pulsed discharge switch with the hollow electrode configuration. This paper experimentally investigates the pre-breakdown processes of a single-gap pseudospark switch triggered from the anode side. The species and contents of impurities on copper electrode surface are firstly analyzed, which mainly include C, N and O. Then, at the same conditions, the trigger delay and jitter of triggering from the anode side are significantly higher than the cathode side, as well as the minimum voltage and pressure that the switch can be triggered. The evolution of the discharge region of the pseudospark switch triggered from the anode side is observed by the ICCD camera for the first time in the literature. The time-resolved images show that the luminescence firstly appears in the hollow anode where the trigger discharge happens and then in the hollow cathode, the cathode hole, the main gap and the anode hole successively, which is completely different from triggering from the cathode side. Finally, a model considering the migration and collisions of ions and fast atoms is established, and it points out that the ion flux from the hollow anode plays an important role in triggering from the anode side. The key processes also include the formations of the positive space charge column inside the hollow cathode and the intense secondary electron emission as an electron source for the main gap.

Probing the Dynamics of Low-Overpotential CO2-to-CO Activation on Copper Electrodes with Time-Resolved Raman Spectroscopy.

Oxide-derived copper electrodes have displayed a boost in activity and selectivity toward valuable base chemicals in the electrochemical carbon dioxide reduction reaction (CO2RR), but the exact interplay between the dynamic restructuring of copper oxide electrodes and their activity and selectivity is not fully understood. In this work, we have utilized time-resolved surface-enhanced Raman spectroscopy (TR-SERS) to study the dynamic restructuring of the copper (oxide) electrode surface and the adsorption of reaction intermediates during cyclic voltammetry (CV) and pulsed electrolysis (PE). By coupling the electrochemical data to the spectral features in TR-SERS, we study the dynamic activation of and reactions on the electrode surface and find that CO2 is already activated to carbon monoxide (CO) during PE (10% Faradaic efficiency, 1% under static applied potential) at low overpotentials (−0.35 VRHE). PE at varying cathodic bias on different timescales revealed that stochastic CO is dominant directly after the cathodic bias onset, whereas no CO intermediates were observed after prolonged application of low overpotentials. An increase in cathodic bias (−0.55 VRHE) resulted in the formation of static adsorbed CO intermediates, while the overall contribution of stochastic CO decreased. We attribute the low-overpotential CO2-to-CO activation to a combination of selective Cu(111) facet exposure, partially oxidized surfaces during PE, and the formation of copper-carbonate-hydroxide complex intermediates during the anodic pulses. This work sheds light on the restructuring of oxide-derived copper electrodes and low-overpotential CO formation and highlights the power of the combination of electrochemistry and time-resolved vibrational spectroscopy to elucidate CO2RR mechanisms.

Optimization of Anticorrosive PANi and PPy Synthesis Conditions on ZnNiMo Coated Copper Electrode Surface with Box Behnken Design

Optimization of Anticorrosive PANi and PPy Synthesis Conditions on ZnNiMo Coated Copper Electrode Surface with Box Behnken Design

PH Micro-Sensor from Irox SECM Microelectrode for Local pH Measurement While Chromium Electrodeposition

In this work, it will be presented the chromium electrodeposition mechanisms with the use of a Scanning ElectroChemical Microscopy (SECM) micro-electrode. Among several factors, the pH is key to achieve even a metallic deposit. pH buffers and complexing agents are often used for this purpose [1] but in the vicinity of the electrode, at the electrode/electrolyte interface, strong variations are highly likely to occur. To this respect, since pH is a key parameter, a pH micro-electrode is intended to be developed to scan the pH gradient upon the electrodeposition of chromium. The first part of this work is so devoted to the pH micro-electrode realization from microelectrode on which iridium oxide is deposited. Iridium oxide has been reported to be suitable for local pH sensing [2-4]. Different parameters have been studied such as IrOx thickness and thermal treatment. The addition of Nafion has been assessed as well to achieve a tradeoff between fast response time, good selectivity and good stability [5]. An optimized IrOx micro-electrode has been obtained and used as SECM micro-electrode to get the evolution of the pH at the electrode/electrolyte interface upon electrodeposition. Different micro-electrode diameters have been used to improve the resolution. These results are promising and will allow going further to the development of chromium electrodeposition electrolyte helping to select the different complexing agents.[1] D. Del Pianta et al. Determination of the chromium(III) reduction mechanism during chromium electroplating. Electrochimica Acta (2018) 234-241.[2] H. A. Elsen et al. Effects of electrodeposition conditions and protocol on the properties of iridium oxide pH sensors electrodes. J. Electrochem Soc. 156 (2009).[3] C. S. Santos et al. Fabrication and use od dual-function iridium oxide coated gold SECM tips. An application to pH monitoring above copper electrode surface during nitrate reduction. Electroanalysis 28 (2016) 1441-1447.[4] Z. Zhu et al. A fabrication of iridium oxide film pH micro-sensor on Pt ultramicroelectrode and its application on in-situ pH distribution of 316 stainless steel corrosion at open circuit potential. Sensors and Actuators B 25 (2018) 1974-1982.[5] I. G. Borislav et al. Thin-film IrOx pH microelectrode for microfluidic-based microsystems. Biosensors and Bioelectronics 21 (2005) 248-256.

Fabrication and characterization of a flexible nanogenerator using reverse electrowetting concept

Many researchers are interested in powering sensors and electrical circuits in wireless networks through energy harvesting from environmental waste energies. In this study, a flexible nanogenerator is designed and fabricated based on the reverse electrowetting concept. The performance of the nanogenerator has been investigated in different conditions including various bias voltage, different excitation frequency, and several external loads. The nanogenerator comprises of water droplets, as a strong dipole fluid, and two dielectric layers; polymethylsiloxane polymer. The latter has good hydrophobicity and flexibility. These two dielectric layers are formed on the surface of copper electrodes by using a spin coater. It is shown that increasing the excitation frequency augments the generated power to some extent that the capacitor is not fully discharged. The nanogenerator power output increases with the external load up to equality between the external load and the nanogenerator's internal resistance. The results show that the fabricated nanogenerator can generate a power density equal to 1.08 W/m2 using 1 ml water droplet, 7V bias voltage, and an excitation frequency of 1 Hz.

PH Micro-Sensor from IrOx SECM Microelectrode for Local pH Measurement While Chromium Electrodeposition

In this work, it will be presented the chromium electrodeposition mechanisms with the use of a Scanning ElectroChemical Microscopy (SECM) micro-electrode. Among several factors, the pH is key to achieve even a metallic deposit. pH buffers and complexing agents are often used for this purpose [1] but in the vicinity of the electrode, at the electrode/electrolyte interface, strong variations are highly likely to occur. To this respect, since pH is a key parameter, a pH micro-electrode is intended to be developed to scan the pH gradient upon the electrodeposition of chromium. The first part of this work is so devoted to the pH micro-electrode realization from microelectrode on which iridium oxide is deposited. Iridium oxide has been reported to be suitable for local pH sensing [2-4]. Different parameters have been studied such as IrOx thickness and thermal treatment. The addition of Nafion has been assessed as well to achieve a tradeoff between fast response time, good selectivity and good stability [5]. An optimized IrOx micro-electrode has been obtained and used as SECM micro-electrode to get the evolution of the pH at the electrode/electrolyte interface upon electrodeposition. Different micro-electrode diameters have been used to improve the resolution. These results are promising and will allow going further to the development of chromium electrodeposition electrolyte helping to select the different complexing agents.[1] D. Del Pianta et al. Determination of the chromium(III) reduction mechanism during chromium electroplating. Electrochimica Acta (2018) 234-241.[2] H. A. Elsen et al. Effects of electrodeposition conditions and protocol on the properties of iridium oxide pH sensors electrodes. J. Electrochem Soc. 156 (2009).[3] C. S. Santos et al. Fabrication and use od dual-function iridium oxide coated gold SECM tips. An application to pH monitoring above copper electrode surface during nitrate reduction. Electroanalysis 28 (2016) 1441-1447.[4] Z. Zhu et al. A fabrication of iridium oxide film pH micro-sensor on Pt ultramicroelectrode and its application on in-situ pH distribution of 316 stainless steel corrosion at open circuit potential. Sensors and Actuators B 25 (2018) 1974-1982.

Microfluidic Rapid Prototype Enzymatic Biofuel Cell Based on a Nanocomposite

Here, a low-cost glucose/O2 Y-shaped microfluidic biofuel cell was developed using a printed circuit board for microelectrode construction. A double-side tape based on the pressure-sensitive adhesive was used for microchannel fabrication. A nanocomposite that consisted of reduced graphene oxide gold nanoparticles (AuNPs), and poly neutral red connected to enzymes was applied on the copper electrode surface. The Aspergillus niger glucose oxidase enzyme and Mytheliophthora thermophile laccase were used to prepare the modified anodic and cathodic electrodes. Different procedures such as cyclic voltammetry scanning electron microscope coupled with energy-dispersive x-ray spectroscopy (EDX), and atomic force microscopy were used to scan the modified electrodes. SEM/EDX microanalysis displayed the structural and morphological properties of the proposed nanocomposite. The biofuel cell performance demonstrated a maximum power density of 36 μW cm−2, an open-circuit voltage of 0.5 V, and a flow rate of 50 μl min−1. The proposed rapid technique with RGO/AuNPs/PNR bioelectrodes is a good approach for finding low-cost microfluidic biofuel cells.

Effect of SiO2 Films with Different Thickness Deposited on Copper Electrode Surface for Insulation Properties of Propylene Carbonate

In this work, 100, 200, and 400 nm SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> films are deposited on the electrode surface by magnetron sputtering, and the effect of film thickness on the insulation performance of propylene carbonate is studied. We use the Weibull distribution to calculate the breakdown voltage of propylene carbonate under different conditions. Space charge distribution of the liquid is measured based on the Kerr effect. Test results show that the breakdown voltage of propylene carbonate increases from 8.4 to 18.7% with increasing film thickness compared with the case where the SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film is not deposited. Bipolar injection mode of space charge is not affected by the increase of SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film thickness, but the amount of space charge injection is significantly reduced. The thicker the SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film deposited on the electrode surface, the higher the ratio of increasing the breakdown voltage of propylene carbonate, but the smaller the magnitude of the increase.

Simulations of hydrogen outgassing and sticking coefficients at a copper electrode surface: Dependencies on temperature, incident angle and energy

The authors show simulations of adsorption and absorption at normal incidence as a function of energy in hydrogen outgassing.

Effects of pH on inhibitor-doped hybrid protective sol–gel coatings on the copper electrode surface

In this study, hybrid inhibitor-doped sol–gels were synthesized using 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (AHMT), 3-glycidoxypropyltrimethoxysilane (GPTMS), and tetraethoxysilane (TEOS) at different pH values (4, 7, and 11). The fabricated sol–gels were applied as coatings via a self-assembly method to obtain corrosion resistance for copper substrates in 3.5% NaCl. The AHMT-doped hybrid sol–gel coatings were characterized through different methods. Interactions between the hybrid AHMT-doped sol–gel and copper metal were demonstrated by quantum chemical calculations based on the density functional theory and molecular dynamics simulations. The results from electrochemical impedance spectroscopy and potentiodynamic polarization analysis of the hybrid AHMT-doped sol–gel coating at pH 4 demonstrated enhanced corrosion resistance compared to the data from the tests at pH values of 7 and 11. This can be explained by the formation of an effectively packed layer, which acted as a physical barrier against corrosive chloride ions that protected copper metal against corrosion.

Anticorrosive Properties of Green Silver Nanoparticles to Prevent Microbiologically Influenced Corrosion on Copper in the Marine Environment

Microbiologically influenced corrosion is a global problem especially materials used in marine engineering. In that respect, inhibitors are widely used to control fouling and corrosion in marine systems. Most techniques used in inhibitor production are expensive and considered hazardous to the ecosystem. Therefore, scientists are motivated to explore natsural and green products as potent corrosion inhibitors especially in nano size. In this study, antibacterial and anticorrosive properties of green silver nanoparticles (AgNPs) were studied through weight loss, electrochemical characterization, and surface analysis techniques. The corrosion of copper (Cu) in artificial seawater (ASW), Halomonas variabilis (H. variabilis) NOSK, and H. variabilis + AgNPs was monitored using electrochemical measurements like open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization curves. AgNPs showed excellent antibacterial activity against pathogenic microorganisms. Electrochemical studies demonstrate a noticeable decrease in OCP and current density in ASW containing H. variabilis + AgNPs compared to both ASW and ASW inoculated with bacterium, which confirmed the decrease of corrosion rate of copper. Furthermore, the obtained voltammograms show that the silver nanoparticles were adsorbed on the copper electrode surface from the corrosion solution. Thus, the results prove that the novel idea of green silver nanoparticles acts as an anticorrosive film in the marine environment.

Liquid metal motor.

SummaryLiquid metal has demonstrated an enormous potential for developing soft functional devices and machines. However, current liquid metal enabled machines suffer from several issues, such as the requirement of a liquid environment, generation of weak actuating forces, and insufficient maneuverability. To overcome these restrictions, here, a motor is developed based on the electrical actuation of liquid metal droplets without the need for conventional electromagnets. The approach is distinguished by (1) the encapsulation of electrolyte and multiple liquid metal droplets within an enclosed system, and (2) the creation of stable and continuous torque outside a liquid environment. In addition, a liquid metal electrical brush is introduced to operate the motor with low friction and low wear. The unique driving mechanism endows the motor with several advantages, including low friction, no sparking, low noise, versatile working environment, and being built from soft materials that could offer new opportunities for developing soft robotics.

PH Micro-Sensor from IrOx SECM Microelectrode for Local pH Measurement While Chromium Electrodeposition

In this work, it will be presented the chromium electrodeposition mechanisms with the use of a Scanning ElectroChemical Microscopy (SECM) micro-electrode. Among several factors, the pH is key to achieve even a metallic deposit. pH buffers and complexing agents are often used for this purpose [1] but in the vicinity of the electrode, at the electrode/electrolyte interface, strong variations are highly likely to occur. To this respect, since pH is a key parameter, a pH micro-electrode is intended to be developed to scan the pH gradient upon the electrodeposition of chromium. The first part of this work is so devoted to the pH micro-electrode realization from microelectrode on which iridium oxide is deposited. Iridium oxide has been reported to be suitable for local pH sensing [2-4]. Different parameters have been studied such as IrOx thickness and thermal treatment. The addition of Nafion has been assessed as well to achieve a tradeoff between fast response time, good selectivity and good stability [5]. An optimized IrOx micro-electrode has been obtained and used as SECM micro-electrode to get the evolution of the pH at the electrode/electrolyte interface upon electrodeposition. Different micro-electrode diameters have been used to improve the resolution. These results are promising and will allow going further to the development of chromium electrodeposition electrolyte helping to select the different complexing agents.[1] D. Del Pianta et al. Determination of the chromium(III) reduction mechanism during chromium electroplating. Electrochimica Acta (2018) 234-241.[2] H. A. Elsen et al. Effects of electrodeposition conditions and protocol on the properties of iridium oxide pH sensors electrodes. J. Electrochem Soc. 156 (2009).[3] C. S. Santos et al. Fabrication and use od dual-function iridium oxide coated gold SECM tips. An application to pH monitoring above copper electrode surface during nitrate reduction. Electroanalysis 28 (2016) 1441-1447.[4] Z. Zhu et al. A fabrication of iridium oxide film pH micro-sensor on Pt ultramicroelectrode and its application on in-situ pH distribution of 316 stainless steel corrosion at open circuit potential. Sensors and Actuators B 25 (2018) 1974-1982.

Experimental and theoretical studies of cinnamyl alcohol as a novel corrosion inhibitor for copper foils in rolling oil

AbstractCinnamyl alcohol (CA) was added to the rolling oil of copper foils as a novel corrosion inhibitor, and its anticorrosion performance and mechanism were studied using potentiodynamic polarization and electrochemical impedance spectroscopy. Microstructure and chemical composition of the copper electrode surface were analyzed by scanning electron microscopy, energy‐dispersive spectroscopy, and X‐ray photoelectron spectroscopy. The results showed that CA acted as a mixed‐type inhibitor, and the maximum inhibition efficiency of 87.7% was achieved at 2.4 mM. Moreover, a protective film was formed on the copper surface, which attributed to the C–OH groups in the CA molecule. The absorption of CA on the copper surface was physisorption, which conformed to Langmuir adsorption isotherm, with a standard adsorption free energy of −11.38 kJ/mol. In the presence of CA, some flaky corrosion products changed into granular corrosion products. The synergistic effect of the granular corrosion products (copper chloride hydroxide) and the CA film further decreased the corrosion rate.

PH Micro-Sensor from Modified Pt SECM Microelectrode for Local pH Measurement While Chromium Electrodeposition

In this work, it will be presented the chromium electrodeposition mechanisms with the use of a Scanning ElectroChemical Microscopy (SECM) micro-electrode. Among several factors, the pH is key to achieve even a metallic deposit. pH buffers and complexing agents are often used for this purpose [1] but in the vicinity of the electrode, at the electrode/electrolyte interface, strong variations are highly likely to occur. To this respect, since pH is a key parameter, a pH micro-electrode is intended to be developed to scan the pH gradient upon the electrodeposition of chromium. The first part of this work is so devoted to the pH micro-electrode realization from a platinum microelectrode on which iridium oxide is deposited. Iridium oxide has been reported to be suitable for local pH sensing [2-4]. Different parameters have been studied such as IrOx thickness and thermal treatment. The addition of Nafion has been assessed as well to achieve a tradeoff between fast response time, good selectivity and good stability [5]. An optimized IrOx micro-electrode has been obtained and used as SECM micro-electrode to get the evolution of the pH at the electrode/electrolyte interface upon electrodeposition. Different micro-electrode diameters have been used to improve the resolution. These results are promising and will allow going further to the development of chromium electrodeposition electrolyte helping to select the different complexing agents.[1] D. Del Pianta et al. Determination of the chromium(III) reduction mechanism during chromium electroplating. Electrochimica Acta (2018) 234-241.[2] H. A. Elsen et al. Effects of electrodeposition conditions and protocol on the properties of iridium oxide pH sensors electrodes. J. Electrochem Soc. 156 (2009).[3] C. S. Santos et al. Fabrication and use od dual-function iridium oxide coated gold SECM tips. An application to pH monitoring above copper electrode surface during nitrate reduction. Electroanalysis 28 (2016) 1441-1447.[4] Z. Zhu et al. A fabrication of iridium oxide film pH micro-sensor on Pt ultramicroelectrode and its application on in-situ pH distribution of 316 stainless steel corrosion at open circuit potential. Sensors and Actuators B 25 (2018) 1974-1982.[5] I. G. Borislav et al. Thin-film IrOx pH microelectrode for microfluidic-based microsystems. Biosensors and Bioelectronics 21 (2005) 248-256.

Scuba-diving spiders inspire carbon dioxide conversion

Inspired by a scuba-diving spider, researchers have made water-repelling copper electrode surfaces that boost carbon dioxide reduction by trapping the gas in bubbles (Nat. Mater. 2019, DOI: 10.1038/s41563-019-0445-x). Compared to conventional electrodes, this design converts five times as much CO2 into the valuable chemicals ethylene and ethanol. Electrochemical processes that use wind or solar power to convert CO2 into hydrocarbons could be a win-win for the environment. The process would provide a use for CO2 captured from the air or other sources, provide a way to store intermittent renewable electricity, and offer an alternative source of chemicals that are otherwise made from petroleum. Copper has proved the best CO2-reducing electrocatalyst so far. Researchers typically immerse copper-coated porous electrodes in an aqueous solution containing CO2. When electricity is applied, copper triggers the reduction of CO2 into a mix of carbon monoxide and other products such as methane, ethylene, and ethanol. But