Electrochemical Investigation Research Articles

Renewable cold plasma exposed activated carbon-derived eucalyptus leaves (EL) as electrode in fabricating low-cost energy storage devices

ABSTRACT The activated carbon made from Eucalyptus leaves was created using an environmentally friendly physical activation process, and it was then subjected with the low temperature plasma to increase its surface area and porosity, as shown by structural and morphological characteristics. The nanoparticles’ surface layers are altered by the plasma treatment, improving surface characteristics like wettability, adhesion, and surface area that were investigated using structural, morphological, and electrochemical studies. The air-plasma-treated KOH exhibits a specific capacitance of 1591 F/g for 1.5 mA, which can be utilized to prepare an electrode material for the energy storage application. The electrochemical investigation was conducted for the untreated and air, oxygen-plasma-treated carbon, demonstrating the better specific capacitance for the air plasma treatment, which can be used to prepare an electrode material for the low-cost fabrication of the devices.

Chemical, electrochemical, and quantum investigation into the use of an organophosphorus derivative to inhibit copper corrosion in acidic environments

In order to protect the copper against corrosion, a novel corrosion inhibitor known as diphenyl ((2-aminoethyl) amino) (4-methoxyphenyl) methyl) phosphonate (DAMP) was developed. Acid solutions of HCl and H2SO4 were the aggressive solutions employed in this study. Analysis using the FT-IR, 1H-NMR, 31P-NMR, 13C-NMR and BET confirmed that the DAMP was successfully synthesized. The anti-corrosion capabilities of DAMP are evaluated using a combination of chemical, electrochemical and quantum studies. The DAMP has been found to be crucial in preventing the corrosion of copper in both HCl and H2SO4 acid. This was obviously implied by the observation that the corrosion rate of copper in acid solutions decreased when DAMP was added. It is significant to note that 180 ppm produced the highest levels of inhibiting efficiency (96.6% for HCl and 95.2% for H2SO4). The tendency of DAMP to adsorb on the surface of copper through its hetero-atoms (O, N, and P) is the main factor for the anti-corrosion capabilities of DAMP. Results from SEM/EDX tests supported this. The actual adsorption takes place via various active centers, physical and chemical mechanisms that are coordinated with the estimated quantum parameters. Additionally, the adsorption of DAMP adheres to the Langmuir isotherm.

Incorporation of Ag in Co9S8-Ni3S2 for Predominantly Enhanced Electrocatalytic Activities for Oxygen Evolution Reaction: A Combined Experimental and DFT Study.

Electrodeposition of abundant metals to fabricate efficient and durable electrodes play a viable role in advancing renewable electrochemical energy technologies. Herein, we deposit Co9S8-Ag-Ni3S2@NF onto nickel foam (NF) to form Co9S8-Ag-Ni3S2@NF as a highly efficient electrode for oxygen evolution reaction (OER). The electrochemical investigation verifies that the Co9S8-Ag-Ni3S2@NF electrode exhibits superior electrocatalytic activity toward OER because of its nanoflowers' open-pore morphology, reduced overpotential (η10 = 125 mV), smaller charge transfer resistance, long-term stability, and a synergistic effect between various components, which allows the reactants to be more easily absorbed and subsequently converted into gaseous products during the water electrolysis process. DFT calculation also reveals that the introduction of Ag (222) surface into the Co9S8 (440)-Ni3S2 (120) system increases the electronic density of states per unit cell of a system and significantly reduces the energy barriers of intermediates for OER, leading to enhanced electrocatalytic activity for OER. This study showcases the innovation of employing trimetallic nanomaterials immobilized on a conductive, continuous porous three-dimensional network formed on a nickel foam (NF) substrate as a highly efficient catalyst for OER.

Synthesis of graphitic carbon nitride (g-C3N4) by high-temperature condensation for electrochemical evaluation of dichlorophen and thymol in environmental trials

The work deals with synthesizing carbon-based nanomaterial, i.e., graphitic carbon nitride, which was carried out using the high-temperature condensation method. Graphitic carbon nitride is characterized by cost efficiency, increased thermal resilience, a two-dimensional molecular layer structure, biocompatibility and stability. These properties can be used in the electrochemical investigations of fungicides such as dichlorophen and thymol. The synthesized nanomaterial was first characterized using XRD, SEM, UV-DRS, BET, FTIR, CV and EIS investigations. The cyclic voltammetry behavior of dichlorophen and thymol shows the proton-coupled irreversible electron transfer process at a modified carbon paste electrode with the participation of same number of protons and electrons. The developed sensor exhibited good detection limits for the dichlorophen and thymol as low as 15.3 nM and 12.0 nM with the sensitivity of 126.8 µA·µM−1·cm−2 and 59.2 µA·µM−1·cm−2, respectively. The applicability of the developed sensor was tested in spiked soil and water samples, and good recoveries were achieved with a % RSD of 1.67 and 1.30, respectively. The anti-interference responses to metal ions demonstrate the selectivity (qualitative) of the developed sensor in the electrochemical detection of dichlorophen and thymol. In the future, the sensor developed would offer the potential to sensitively and selectively detect other pesticide molecules in environmental samples.

The impact of a TiO2/r-GO composite material on the performance of electron transport electrodes of dye sensitized solar cells.

In dye sensitized solar cells, the role of the electron transport layer is crucial because it makes it easier for photo-generated electrons to get from the dye to the external circuit. In DSSCs, the utilization of TiO2 is likely to be given preference in the production of electron transport electrodes due to its notable characteristics such as its expansive surface area, porosity, and capacity to scatter light. Nevertheless, the presence of heterogeneity within the mesoporous structure increases the likelihood of TiO2 aggregation, which subsequently diminishes the beneficial impact of TiO2 on the performance of DSSCs. In this context, reduced graphene oxide (r-GO) is introduced as an additive into the TiO2 network during the preparation of TiO2/reduced graphene oxide (r-GO) composites. The integration of r-GO with TiO2 has been recognized as a promising approach to enhance electron transport and electron lifespan, owing to remarkable qualities exhibited by r-GO. The present investigation involved the synthesis of a composite material including titanium dioxide/reduced graphene oxide (TiO2/r-GO) through the utilization of the co-precipitation technique. Following this, the generated TiO2/r-GO composite material and pure TiO2 were deposited on FTO through electrophoretic deposition to obtain an electron transport electrode of a dye sensitized solar cell. It should be noted that when r-GO was combined with TiO2, the performance of DSSCs improved notably compared to pure TiO2. As a result, the findings of this work have significant implications for the advancement of the TiO2/r-GO composite deposited through electrophoretic deposition. The power conversion efficiency reached 6.64% with the addition of r-GO in the metal oxide electron transport electrode. The obtained findings align with the outcomes of electrochemical impedance investigations in which the electrode constructed with TiO2/r-GO exhibits reduced electron transport resistance (RCt) at the anode/dye/electrolyte interface, as well as lower overall resistance (Rtotal) in comparison to TiO2-based DSSCs. These advancements have the potential to be employed in commercial DSSC manufacturing.

Ultrafast and selective detection of dopamine by DC sputtered highly oriented CuO thin films: Effect of electroactive interfering agents and temperature

Dopamine and serotonin are two neurotransmitters that play critical role in human physiology. In this work, it has been aimed to synthesize a chip-based sensing platform that can detect dopamine precisely in a non-enzymatic way in presence of a series of electroactive interfering agents. Copper oxide (CuO), a p-type material with excellent surface and electrochemical properties, has been deposited through direct current (DC) sputtering technique on indium doped tin oxide (ITO) coated glass substrates as the sensing platform. The structure, phase purity and other essential properties of the modified electrode were established through x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and ultraviolet – visible (UV–Vis) spectroscopy. Detailed electrochemical investigations with the modified electrode have also been carried out using cyclic voltammetry (CV), chronoamperometry (i – t) and electrochemical impedance spectroscopy (EIS) that revealed ultrafast response (10 ms), excellent sensitivity (5.41 µAµM-1cm−2) and low limit of detection (LoD) of 0.46 µM for the electrode towards dopamine. The electrode exhibited sensitivity of 0.37 µAµM-1cm−2 with average LoD of 19.2 µM towards serotonin, which is inferior to dopamine. The threshold response potential was also quite different for dopamine and serotonin. The modified electrode was also found to be nonresponsive to a series of electroactive interfering agents, making it dopamine selective. The role of p-type conductivity of the electrode material towards such selective detection of dopamine was also explained. The electrode was notably reliable from the point of view of electrochemical performance and structural stability. Real sample analysis was also carried out by taking urine sample from adult male human.

Ferrocene-based amides, amines and alcohols as a platform for the design and synthesis of redox-active hybrids: Synthesis, electrochemical and computational studies

Herein we report on the synthesis and characterization of a number of the simplest ferrocenes, namely Fc-amides (4a-i), Fc-amines (5a-i) and Fc-alcohol (1), as starting materials for the synthesis of redox-active ferrocene-modified compounds. Suitable conditions allowed preparing a seria of various ferrocenes with aliphatic and aromatic substituents in good to high yields. The title products were characterized by 1H, 13C NMR, IR, ESI-MS analytical methods. The structure of ferrocenyl(ortho-chlorophenyl) methanol (1) was determined by single-crystal X-ray diffraction. Geometrical parameters in compound 1 were calculated using the ab initio MP2/6-31G* method and based on the advanced DFT calculations, DFT wb97xd/6-31G* and DFT wb97xd/6-311+G*. Electrochemical investigations by cyclic voltammetry revealed reversible redox processes for the ferrocenyl amides. Potentials were also calculated using two basis sets, 6-31G* and 6-311+G*, and demonstrated a high degree of correlation with experimental results.

Ag2ZnSnS4 thin films elaborated by co-electrodeposition: Structural, optical and electrochemical investigations

Here, the Ag2ZnSnS4 thin film was electrodeposited on molybdenum (Mo) for the first time using an electrodeposition-sulfurization technique. By adjusting the bath concentration, XRD and Raman analyses confirmed that the tetragonal Ag2ZnSnS4 phase was well elaborated for [Zn2+] = 0.05 M. As [Zn2+] varies, UV–visible reveals a bandgap change in the range 1.35–1.50 eV, with high absorption coefficient in the magnitude of 10−4 cm−1, confirmed by the DFT calculation. Cyclic voltammetry and galvanostatic charge discharge analysis of Ag2ZnSnS4/Mo in 1 M-Na2SO4 electrolyte highlighted the pseudo-capacitor character and delivers higher specific capacitance of 450 F/g, with only a 13 % drop in specific flow capacity when the applied discharge current increases. These results strongly encourage the possible deployment of Ag2ZnSnS4 in energy conversion as well as in energy storage.

Electrochemical investigation of ZnNPs and Zn(OH)2NPs thin films behaviour grown on graphite rod by a two-step electrochemical conversion process

Electrochemical investigation of ZnNPs and Zn(OH)2NPs thin films behaviour grown on graphite rod by a two-step electrochemical conversion process

Electrochemical and Theoretical Modelled Reduction of β‐Diketone Inspired Chalcones

AbstractThe growing interest in synthesizing electrochemically active organic ligands stems from extensive reports highlighting the applications of redox‐active organic molecules. These molecules play a crucial role in capturing and converting CO2 into valuable organic compounds, including carbonates used as solvents in lithium batteries. In this study, we present an electrochemical investigation of two chalcone derivatives, referred to as (1) and (2). We explored the influence of different solvent systems, specifically acetonitrile and dimethyl sulfoxide, on the reduction potential of these chalcones. The reported chalcone derivatives were characterized using various analytical techniques, including UV/Visible spectroscopy, Fourier Transform Infrared spectroscopy, Proton and Carbon‐13 nuclear magnetic resonance, as well as mass spectrometry. The characterization of the reported chalcones, exhibiting properties of both β‐diketones and 2‐hydroxyphenones, is underscored by a density functional theory (DFT) study of chalcones (1) and (2). This research establishes a correlation between the energies calculated through DFT and the experimental reduction potentials of chalcones (1) and (2), in comparing them with a series of β‐diketones and 2‐hydroxyphenones.

Fabrication of Ni-Polyaniline/Graphene Oxide Composite Electrode with High Capacitance and Water Splitting Activity.

The Ni-PANI@GO composite electrode was fabricated via cost effective electrodeposition technique. According to the XRD, FTIR, Raman, SEM, and XPS analyses revealed that the nickel doped PANI@GO composite has been fabricated on the surface of the nickel foam. Addition of nickel significantly enhanced interaction between graphene with PANI leading to higher degree of polyaniline doping though imine groups. Electrochemical investigation revelated the significant performance of the Ni-PANI@GO composite electrode, boosting an impressive capacitance of 4480 F/g at 40 A/g, surpassing previous Ni-foam-based binder-free electrodes. Notably, Ni-PANI@GO electrode displayed excellent catalytic activity in both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), generating a considerable volume of the gas bubbles at relatively modest overpotentials of 279 mV and 244 mV respectively. This event allows for the achievement of 20 mA·cm-2 current density. Furthermore, in the laboratory-scale water electrolyzer, a low cell voltage of 1.72 V was achieved, facilitating a water-splitting current density of 20 mA·cm-2. This study underscores the premising potential for the real-world device's application of the versatile Ni-PANI@GO composite electrode.

Enhancing the energy storage performance of titanium dioxide electrode material by green doping of Nd2O3 nanoparticles for electrochemical supercapacitors

Doping of sesquioxide alloy onto TiO2 nanomaterials was carried out in a novel green chemistry method using Corallo carpus epigaeus to fabricate the electrodes for pseudocapacitors. The conducted X-ray diffraction studies demonstrated the tetragonal phase of TiO2 and hexagonal phase of Nd2O3 nanomaterials. Morphological analysis revealed the irregular shape of TiO2 materials, each exceeding 100 nm in size, while Nd2O3 materials exhibited a spherical shape within the range of 10-20 nm. Electrochemical investigations unveiled a quasi-rectangular shape in cyclic voltammetric studies and a triangular shape in galvanostatic reactions, suggesting superior electrochemical performance of the electrodes. The doped electrodes exhibited a higher specific capacitance value (785.71 F/g) compared to pure TiO2 (707.14 F/g) at a current density of 1 A/g. These findings affirm the suitability of doped electrode materials for applications in electrical energy storage.

Facile synthesis and electrochemical investigation of graphitic carbon nitride/manganese dioxide incorporated polypyrrole nanocomposite for high-performance energy storage applications

Abstract Manganese dioxide (MnO2) nanoparticles were modified by graphitic carbon nitride (GCN) and polylpyrrole (Ppy) to enhance their electrochemical performance. The surface influence, crystalline structure, and electrochemical performance of the Ppy/GCN/MnO2 material were characterized and compared with those of pristine MnO2. It is found that surface modification can improve the structural stability of MnO2 without decreasing its available specific capacitance. The electrochemical properties of synthesized Ppy/GCN/MnO2 electrode were evaluated using cyclic voltammetry (CV) and AC impedance techniques in 5 M KOH electrolyte. Specific capacitances of 486, 815, 921, and 1377 F/g were obtained for MnO2, Ppy/MnO2, GCN/MnO2, and Ppy/GCN/MnO2, respectively, at 5 A/g. This improvement is attributed to the synergistic effect of GCN and Ppy in the Ppy/GCN/MnO2 electrode material. The Ppy/GCN/MnO2 electrode in KOH has average specific energy and specific power densities of 172 Wh kg−1 and 2065 W kg−1, respectively. Only 2 % of the capacitance’s initial value is lost after 10,000 cycles. The resulting Ppy/GCN/MnO2 nanocomposite had very stable and porous layered structures. This work demonstrates that Ppy/GCN/MnO2 nanomaterials exhibit good structural stability and electrochemical performance and are good materials for supercapacitor applications.

Deposition of nickel-titanium coating on stainless steel 316L by direct current sputtering for bio-implants: Electrochemical, microstructural, and morphological investigations

In general, the application of coatings provides vital protection for medical devices with a host of beneficial properties such as biostability and biocompatibility, chemical barrier, and micro-encapsulation. In the current work, a nickel-titanium (NiTi) system was deposited on stainless steel (SS316L) by the direct current sputtering (DCS) technique to estimate the corrosion behavior in the simulated body fluid (SBF) at 37 °C. The characterization of the coating layer was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDX) techniques to know the phases, elemental composition, and structure of the coating that indicated the formation of the Ni3Ti phase as a flake-shaped structure with 2.6 and 0.4 wt% of Ni and Ti, respectively. The results of atomic force microscopy (AFM) showed a decrease in surface roughness from 25.2 to 11.05 nm after coating due to a decrease in the mean diameter of particles from 710.8 to 579.9 nm after coating. The data corrosion test showed the change of corrosion potential to a more noble value with minimizing the corrosion current density as well as the improvement of resistance after coating from 6.91 × 103 to 25.49 × 103 Ω.cm2 to get protection efficiency equal to 73.9 %. In a cyclic polarization test, it can be seen that the passivity region shifts to lower current density values. Microhardness was also measured to show an increase from 187 to 366 HV due to the selected technique of coating that gives more hardness; the measured wettability did not change the contact angle of the uncoated specimen to keep it at 90°; and finally, the histological analysis did not show any severe infection or inflammation. All these observations can suggest the NiTi coating for bio-applications.

Electrochemical and Quantum Chemical Investigations of novel pyrazole derivatives as a Corrosion Inhibitor for Stainless Steel in 2M H2SO4 medium

Stainless steels play a crucial role in diverse industrial domains. However, due to their exposure to acidic environments, stainless steels undergo the corrosion phenomenon, leading to the deterioration of the material and its properties. Thus, the objective of this work is to study the corrosion inhibition of stainless steel in an H2SO4 2M medium by using two organic compounds, namely Py-3:{1-amino-5,10-dioxo-3-(p-tolyl)-5,10-dihydro-1H-pyrazolo[1,2-b] phthalazine-2-carbonitrile} and Py-4:{1-amino-3-(2-chlorophenyl)-5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]phthalazine-2carbonitrile}. This study was conducted using transient electrochemical methods in conjunction with a theoretical approach. The obtained results demonstrate that the addition of pyrazole compounds in the corrosive medium H2SO4 exhibits excellent inhibitory power against steel corrosion, with an inhibitory efficiency reaching 98%. The tested inhibitors are adsorbed into the surface of the metal by chemical bonds, Moreover, the adsorption of these compounds follows the Langmuir adsorption model. Theoretical calculations based on the Density Functional Theory (DFT) provide a better understanding of the reactivity of tested inhibitor towards stainless steel which they are in good agreement with the experimental findings.

Facile synthesis of SnSe–MnTe nanocomposite as a promising electrode for supercapacitor applications

The biggest problems encountered by the world right now are energy demand and environmental damage because of the exploitation of fossil fuels. Producing and storing energy in an environment-friendly way is increasingly crucial due to the exhaustion of non-renewable resources. Developing a robust energy storing system is essential for efficient energy storage, specifically for renewable energy sources. In this study, tin selenide and manganese telluride (SnSe–MnTe) nanocomposite was synthesized via a sonication method for supercapacitor application. Different physical techniques confirmed the enhanced structural and morphological attributes observed for the SnSe–MnTe nanocomposite. During electrochemical investigations, the SnSe–MnTe nanocomposite exhibited specific capacitance, specific energy (SE) and specific power (SP) of 1502 F/g, 61.05 Wh/kg and 270.5 W/kg at 1.0 A/g, correspondingly. Furthermore, it exhibited outstanding cyclic stability, maintaining its performance across 5000th cycles in an electrolyte (2.0 M KOH). Compared to SnSe (1.25 Ω) and MnTe (0.69 Ω), the charge transfer resistance (Rct) value for SnSe–MnTe (0.3 Ω) was smaller calculated via Nyquist plot. Therefore, transition metal chalcogenide-based nanocomposite has an excellent potential as electrode material for supercapacitor (SCs) and it can also be utilized in different energy storage devices.

Electrochemical investigation of electrophoretically deposited graphene-oxide coating on AZ31 alloy prepared using in-house synthesized few-layer graphene-oxide nanosheets

Magnesium and its alloys possess low density and superior specific strength making it a potential structural metal to be used in different engineering fields. However, its proneness to corrosion limits its applications. In this novel study, an eco-friendly graphene-oxide coating was prepared on AZ31 magnesium alloy via electrophoretic deposition to enhance its anti-corrosion properties. Scanning electron microscopy coupled with energy dispersive spectroscopy, atomic force microscopy, and scratch test were adopted to investigate surface morphology, roughness, chemical composition, and adherence of the coating. The corrosion behaviour of graphene-oxide coated alloy was studied using potentio-dynamic polarization and electrochemical impedance spectroscopy tests in 3.5 wt% NaCl and Borate Buffer solutions. The obtained results demonstrate that the coating developed on AZ31 alloy is smooth and adherent with the hardness of the as-deposited coating measuring as high as 6.0 GPa. In addition, the electrochemical corrosion behaviour studies revealed that the coating significantly increased the corrosion potential (Ecorr) of the alloy towards more noble values (−0.65 V < Ecorr < −0.35 V), with the coated alloys possessing a charge transfer resistance nearly two orders of magnitude greater than their non-coated counterparts. Consequently, the corrosion rate of the coated alloy decreased substantially, indicating that the coating exhibits exceptional corrosion resistance (0.045–0.09 mm/a in 3.5 wt% NaCl and 0.002–0.006 mm/a in Borate Buffer). These findings challenge the conventional beliefs that graphene exhibits strong cathodic behaviour towards anodic materials such as AZ31 alloy. Thus, the outcomes not only have the potential to revolutionize the advancement of graphene-oxide coatings for corrosion resistance but could also possibly expand AZ31 alloy’s applications in the aerospace and automotive sectors.

Low‐Strain and High‐Energy KVPO4F Cathode with Multifunctional Stabilizer for Advanced Potassium‐Ion Batteries

KVPO4F with excellent structural stability and high operating voltage has been identified as a promising cathode for potassium‐ion batteries (PIBs), but limits in sluggish ion transport and severe volume change cause insufficient potassium storage capability. Here, a high‐energy and low‐strain KVPO4F composite cathode assisted by multifunctional K2C4O4 electrode stabilizer is exquisitely designed. Systematical electrochemical investigations demonstrate that this composite cathode can deliver a remarkable energy density up to 530 Wh kg−1 with 142.7 mAh g−1 of reversible capacity at 25 mA g−1, outstanding rate capability of 70.6 mAh g−1 at 1000 mA g−1, and decent cycling stability. Furthermore, slight volume change (~5%) and increased interfacial stability with thin and even cathode–electrolyte interphase can be observed through in situ and ex situ characterizations, which are attributed to the synergistic effect from in situ potassium compensation and carbon deposition through self‐sacrificing K2C4O4 additive. Moreover, potassium‐ion full cells manifest significant improvement in energy density and cycling stability. This work demonstrates a positive impact of K2C4O4 additive on the comprehensive electrochemical enhancement, especially the activation of high‐voltage plateau capacity and provides an efficient strategy to enlighten the design of other high‐voltage cathodes for advanced high‐energy batteries.

Improving the Performance of LiNi0.9Co0.05Mn0.05O2 via Atomic Layer Deposition of ZnxOy Coating

AbstractNickel‐rich cathode materials such as LiNi0.9Co0.05Mn0.05O2 (NMC90) have gained attention due to their ability to deliver high energy densities while being cost‐effective for Lithium‐ion battery manufacturing. However, NMC90 cathodes suffer irreversible parasitic reactions such as electrolyte decomposition, severe capacity fading and impedance build‐up upon prolonged cycling. Herein, we synthesize a conformal ultrathin, surface protection layer on NMC90 powder using ZnxOy via atomic layer deposition technique (ZnxOy@NMC90). Prolonged electrochemical investigation of full cells at high discharge rates of 2 C shows that ZnxOy@NMC90 cells yielded ~31 % improvement in discharge capacity compared to pristine NMC90. Furthermore, operando electrochemical mass spectroscopy studies show that the ZnxOy@NMC90 cells have significantly suppressed electrolyte decomposition as compared to pristine NMC90 cells. Post‐cycling electrochemical impedance spectroscopy studies show that the ZnxOy@NMC90 full cells have significantly reduced impedance compared with pristine NMC90 cells. Additionally, post cycling manganese dissolution studies show that ZnxOy@NMC90 cells have greatly enhanced chemo‐mechanical integrity thereby contributing to improved electrochemical performances. Our results underscore the potential of tailored ZnxOy surface coatings on nickel‐rich cathode materials to address critical challenges in advanced energy storage systems, offering promising prospects for the development of high‐energy‐density lithium‐ion batteries.

Multi-walled carbon nanotubes with embedded nickel sulphide as an effective electrocatalyst for Bi-functional water splitting

Water-splitting presents a viable solution to expanding energy needs. To maximise water-splitting performance, transition metal sulphides, a very efficient electrocatalyst, have been extensively researched. It is unable to generate hydrogen (H2) and oxygen (O2) because to active sites and weak electrical conductivity. Some carbon-based materials offer superior dispersion capacities and bigger active sites for charge transfer to circumvent these restrictions. This work presents an efficient electrocatalyst combining carbon nanotubes (CNTs) and electrochemically active Nickel sulphides, Ni17S18 (NiS), synthesized by using a wet-chemical approach. The improved electrocatalytic performance of NiS@CNTs can be attributed to higher surface area and higher electrical conductivity of CNTs. Furthermore, linear-sweep voltammetry (LSV) and electrochemical impedance analysis (EIS) were also utilized for the electrochemical investigations. The addition of CNTs to NiS showed a over-potential of 330 mV at 40 mA cm−2, with a Tafel slope of 47 mV dec−1 for OER. Similarly, we have also investigated the HER activity of the as-prepared electrocatalysts at the same current density, having a over-potential of 280 mV with a Tafel slope of 102 mV dec−1.