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In this paper, we investigated the spin transport properties of binuclear manganese phthalocyanine (M n 2 P c 2) spintronic devices sandwiched between two nickel electrodes using the non-equilibrium Green's function method in combination with density functional theory. Based on the calculation results, the M n 2 P c 2 device exhibited excellent spin-filtering capabilities, demonstrating an exceptionally high spin filter efficiency (SFE). Irrespective of the parallel or antiparallel orientation of magnetization in the electrodes, we observed that when both manganese atoms were in a spin-up state, the SFE of spin-resolved currents under finite bias and the thermoelectric currents induced by temperature gradients at fixed temperatures were both close to 100%. The large spin Seebeck polarization of the M n 2 P c 2 device was also obtained at low reference temperatures. This study explores the potential for developing multifunctional spintronic single-molecule devices using Ni − M n 2 P c 2. [ABSTRACT FROM AUTHOR]

This study reports on the synthesis of lanthanide oxides triply doped titania, forming a novel hetero-system known as (Sm3+/Eu3+/Tm3+)-TiO 2. An environmentally friendly sol gel method was used to synthesize the energy-efficient (Sm3+/Eu3+/Tm3+)-TiO 2 , and thin films were deposited by spin coating. Electrode and solar cell devices were fabricated under ambient conditions, and rare earth doping enhanced the opto-electronic aspects of the host by narrowing the band gap up to 3.92, 3.85, and 3.56 eV. Particle sizes for the pure and doped materials were 85.15 and 82.72 nm, respectively. With a specific capacitance of 667.34 F g−1, the lanthanide-doped ornamented nickel foam electrode outperformed the pristine electrode, which had a specific capacitance of 169.59 F g−1. Moreover, this electrode exhibited tiny equivalent series resistance (R s) of 0.13 Ω, indicating quicker response kinetics at the interface, in addition to its electrical double layer capacitance behavior. Electrochemical studies revealed that (Sm3+/Eu3+/Tm3+)-TiO 2 semiconductor has a high specific power density of 8157.03 W kg−1, compared to 4079.73 W kg−1 for undoped titania. This improved specific power density demonstrates its suitability for practical scale applications. The produced materials were an excellent HER electro-catalyst with remarkably lower overpotential and Tafel slopes i.e., of 137 mV and 87.6 mV dec−1, in a respective manner, in comparison to the reference TiO 2 with 147 mV and 104.5 mV dec−1, respectively. The electro-catalyst's response to the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) was enhanced upon lanthanide doping. Additionally, this substance successfully retrieved electrons from a perovskite solar cell device, achieving efficiency levels of 16.49 and 16.75 % in both forward and reverse bias with fill factor increase. [ABSTRACT FROM AUTHOR]

This study investigates the preparation of nickel nanostructured electrodes for the enhancement of supercapacitor performance. The nanostructured electrodes are synthesized using nanoporous anodic alumina (NAA) as a template via the pulsed electrodeposition method. Structural properties are examined using field‐emission scanning electron microscopy, while electrochemical characterization is conducted through cyclic voltammetry (CV) and electrochemical impedance spectroscopy. The results reveal that Ni nanorod arrays can be obtained embedded in the NAA matrix and with electrical contact with the aluminum substrate. On average, the rods are spaced 90 nm apart, with a diameter of 70 nm and a length of 2 μm. The Ni@NAA electrode exhibits an enlarged active area and exceptional electrochemical performance, demonstrating remarkable stability over 5000 cycles of CV at a scan rate of 50 mV s−1. Specific capacitance values exceeding 100 mF cm−2 and maximum charging times of less than 10 min are reported, highlighting its suitability for high‐power energy devices requiring pseudo‐supercapacitance. The study underscores the significance of nanostructured electrodes in advancing energy storage technologies and presents promising prospects for practical applications. [ABSTRACT FROM AUTHOR]

Development of high capacity and long cycle life electrode materials is essential to improving energy storage capacity in electrochemical rechargeable devices. In order to be commercially viable, the synthesis of these materials must be straightforward, cost-effective, and ideally a single-step process. We present a binder-free synthesis method for nickel phosphate hydrate (NiPH) and nickel molybdenum phosphate hydrate (NiMoPH) on nickel foam via a simple hydrothermal process. X-ray diffraction (XRD) patterns confirmed the formation of NiPH and NiMoPH phases, while X-ray photoelectron spectroscopy (XPS) verified the presence of nickel (Ni), molybdenum (Mo), phosphorus (P), and oxygen (O) in the composite. Scanning electron microscopy (FE-SEM) revealed the formation of micro-flowers with plate-like structures in NiPH, which transformed into hexagonal rod-like structures upon the introduction of molybdenum in NiPH. This morphological and phase modification increased the charge storage capacity from 1441 mF/cm2 (NiPH) to 2945 mF/cm2 (NiMoPH) at 20 mA/cm2. The NiMoPH electrode demonstrated excellent capacitance retention of 91.8 % over 10,000 cycles. Additionally, asymmetric supercapacitor (ASS) devices were fabricated using NiPH and NiMoPH as positive electrodes and activated carbon (AC) as the negative electrode. The NiPH//AC and NiMoPH//AC configurations exhibited energy densities of 0.086 and 0.201 mWh/cm2, respectively, with the NiMoPH//AC device maintaining about 90 % capacitance retention over 15,000 cycles. This study demonstrates the potential of incorporating conductive transition metals to enhance electrode material performance in energy storage applications. Hydrothermally synthesized nickel phosphate hydrate (NiPH) and nickel molybdenum phosphate hydrate (NiMoPH) electrode materials for energy storage devices have been reported. The transformation of NiPH microplates into hexagonal rods upon the addition of molybdenum was observed. This structural modification and improved conductivity, induced by the inclusion of molybdenum, enhances the electrochemical energy storage performance of the electrodes. [Display omitted] [ABSTRACT FROM AUTHOR]

Self‐repairing catalysts are useful for achieving alkaline water electrolyzers with long lifetimes under intermittent operation. However, rational methodologies for designing self‐repairing catalysts have not yet been established. Herein, hybrid cobalt hydroxide nanosheets (Co‐ns), with a high deposition (repairing) rate, and β‐FeOOH nanorods (Fe‐nr), with high oxygen evolution reaction (OER) ability, are electrostatically self‐assembled into composite catalysts. This strategy is developed to integrate multifunctionality in self‐repairing catalysts. Positively charged Co‐ns and negatively charged Fe‐nr form uniform composites when dispersed in an electrolyte. These composites are electrochemically deposited on a nickel electrode by electrolysis at 800 mA cm−2. Co‐ns form a conductive mesoporous assembly of CoOOH nanosheets as a support. Fe‐nr are then distributed on the CoOOH nanosheets as active sites for the OER. Because of the high deposition rate of Co‐ns, the amount of Fe‐nr deposited increases 22 times compared to when Fe‐nr is deposited alone, and the OER current density increases 14 times compared to that of Co‐ns alone. The composite self‐repair catalyst shows the highest activity and durability under an accelerated durability test (ADT), and its degradation rate decreases from 84 μV cycle−1 (Fe‐nr only) to 60 μV cycle−1 (composite catalyst) under ADT conditions without repair. [ABSTRACT FROM AUTHOR]

Electrocatalytic urea removal is a promising technology for artificial kidney dialysis and wastewater treatment. Urea electrooxidation was studied on nickel electrocatalysts modified with Cr, Mo, Mn, and Fe. Mass transfer limits were observed for urea oxidation at physiological concentrations (10 mmol L −1). Urea oxidation kinetics were explored at higher concentrations (200 mmol L −1), showing improved performance, but with lower currents per active site. A simplified dialysis model was developed to examine the relationship of mass transfer coefficients and extent of reaction on flowrate, composition, and pH of the reacting stream. For a nickel hydroxide catalyst operating at 1.45 V RHE, 37 °C, and pH 7.1, the model shows a minimum geometric electrode area of 1314 cm2 is needed to remove 3.75 g urea h −1 with a flow rate of 200 mL min −1 for continuous operation. [ABSTRACT FROM AUTHOR]

The hydrogen (H 2) and oxygen (O 2) generation from water has garnered great attention in the field of energy worldwide. Thus, the fabrication of durable, scalable, and efficient electrodes for electrocatalysis is a challenge perceived by most researchers around the globe. The current investigation presents the construction of a highly active, binder-free, and scalable nickel-iron cobalt oxide (NFCO) electrode on a Flexible Stainless Steel Mesh Substrate (FSSM) using the reflux condensation deposition method. Interestingly, the as-prepared electrode (NFCO@FSSM) exhibited a very low overpotential of 260 mV at 10 mA cm−2 which outperformed the previously reported nickel and cobalt-based electrodes. The practical applicability was investigated by characterizing the NFCO@FSSM electrode after a 200 h durability study. The NFCO@FSSM electrode (anode) with FSSM electrode (cathode) could generate 34.6 L O 2 over 200 h using a prototype electrolysis setup. This is ascribed to the high electrochemical active sites, multiple oxidation states, and rapid electron transfer. This work provides a new perspective on introducing iron in nickel and cobalt-based electrodes to produce economic and scalable electrodes for efficient oxygen evolution reaction (OER). Development of sustainable, highly active, scalable, and binder-free NFCO@FSSM electrode for the bulk production of O 2. [Display omitted] • Scalable and binder-free synthesis of nickel-iron-cobalt-oxide electrode. • The electrode exhibits a low overpotential of 260 mV@10 mA cm−2. • The synergistic effect of Ni, Fe, and Co presented improved electrocatalytic activity. • XPS analysis revealed the transfer of electrons from Fe to Co to Ni. • The scale-up device shows 34.6 L of oxygen evolution in 200 h. [ABSTRACT FROM AUTHOR]

Hydrogen pumps, crafted from proton-conductive ceramic electrolyte and paired with either oxide or metallic electrodes, have been designed for the extraction of hydrogen isotopes from helium gas mixtures containing 0.1 % hydrogen isotopes, particularly within the context of TES for nuclear fusion reactors. This study presents the electrochemical hydrogen permeation research conducted on the perovskite proton conductor materials BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb) and BaZr 0.8 Y 0.16 Ni 0.04 O 3-δ (BZYN) under these operational conditions. It was observed that nickel electrodes provided superior performance over SrFe 0.8 Mo 0.2 O 3-δ (SFM) electrodes in terms of hydrogen extraction efficiency. Hydrogen pumps that integrated BZCYYb as the electrolyte with nickel electrodes showed enhanced efficiency, while those utilizing BZYN as the electrolyte coupled with nickel electrodes demonstrated greater stability. Furthermore, the study explored the voltammetric nonlinearity at low hydrogen concentrations and the dependency of concentration polarization efficiency on both voltage and temperature, aiming to establish optimal conditions that balance stability and efficiency for both types of hydrogen pumps. [ABSTRACT FROM AUTHOR]

In this study, the electronic engineering of a high-valent active site for enhanced oxygen evolution reaction (OER) was achieved through the electrochemical pre-cathodic treatment method (EPCTM). This method involves applying a cathodic potential to the drop-cast working electrode of Mn-substituted nickel ferrite (Ni1−xMnxFe2O4; where x = 0.0, 0.2, and 0.4) electrocatalysts. X-ray photoelectron spectroscopy analysis revealed an increase in the ratios of Ni3+/Ni2+ and Mn3+/Mn2+ in Ni1−xMnxFe2O4 after EPCTM followed by OER, leading to an enhancement in electrochemical OER current density at 600 mV overpotential by 3.65 times for x = 0.0, 5.56 times for x = 0.20, and 4.72 times for x = 0.40. This enhancement was further supported by a decrease in the slope of the anodic Tafel equation after EPCTM, indicating improved efficiency of the interaction between the working electrode and electrolyte, as a lower Tafel slope suggests better charge exchange at the electrode–electrolyte interface. The positive slope in the Mott–Schottky (MS) plot for all Ni1−xMnxFe2O4 samples confirmed the p-type nature of the electrocatalysts. Additionally, the significant decrease in the slope of the linear portion of the MS plot indicated an increase in carrier concentration after electrochemical pre-cathodic treatment in all Ni1−xMnxFe2O4 samples. This increase in p-type carrier concentration supports the observed increase in the Ni3+/Ni2+ ratio for OER after EPCTM. [ABSTRACT FROM AUTHOR]

Using single‐source precursor route, this work reports the synthesis of the novel chalcogenide heterosystem, i.e., BaS:CoS:La2S3 trichalcogenide heterosystem. With the narrowed band gap energy, BaS:CoS:La2S3 expresses excellent photonic response with 3.47 eV of tailored band gap resulting from chemical synergism. This chalcogenide is marked by superior crystallinity and possessed an average crystallite size of 18.29 nm. Morphologically, BaS:CoS:La2S3 exists in the form of the roughly spherical grains arranged in the irregular manner. The developed chalcogenide is assessed for charge storage by fabricating the electrode using a nickel form as a support. In a 0.1 m KOH background electrolyte, the BaS:CoS:La2S3 adorns electrode excelled in achieving a specific capacitance of 967.24 F g−1. In addition, this trichalcogenide expresses the specific power density of 1659 W kg−1. Fabricated electrode retains original capacitance after different cycles. Regarding electrode–electrolyte interactions, the fabricated electrode shows minimal resistance, with an equivalent series resistance (Rs) of 1.42 Ω as indicated by impedance studies. Additional circuit elements, including CPE (Yo = 2.17 × 10−04, n = 0.71) and Rct (6.97 Ω cm−2), are obtained after circuit fitting for the BaS:CoS:La2S3 trichalcogenide decorated electrode. Exhibiting stable behavior for 43 h, the synthesized material demonstrates profound durability and functionality. [ABSTRACT FROM AUTHOR]

ABSTRACT Energy‐efficient semiconducting BaS:MnS:Sb2S5 has been synthesized using a single source precursor method. The resulting dithiocarbamate metallic sulfide has an average crystallite size of 17.77 nm and a small band gap of 3.82 eV. A functional group investigation revealed the presence of several bonds, including the metal sulfide bond. This sulfide exhibited a double‐step thermal breakdown pattern. BaS:MnS:Sb2S5 particles were formed like cubes and tended to form cube‐like formations. The electrochemical charge‐storing behavior of BaS:MnS:Sb2S5 was investigated using a nickel foam electrode and a sulfide slurry. The fabricated electrode demonstrated a satisfactory capacity for charge storage, with a specific capacitance of 762.83 F g−1. This indicates a substantial amount of potential for long‐term energy storage utilizing electrodes. This electrode has a specific power density of 9084.78 W kg−1 and a low series resistance of (Rs) = 0.71 Ω, as per impedance measurements. Electro‐catalysis produced an OER overpotential and a corresponding Tafel slope of 233 mV and 157 mV/dec from the electrode. Conversely, for HER activity, the obtained overpotential and subsequent Tafel slope were 386 mV and 73 mV dec−1, respectively. [ABSTRACT FROM AUTHOR]

In this work, the binder-free Fe-doped cobalt LDH/nickel foam (CoFe LDH/NF) electrode was prepared using the hydrothermal method. To achieve higher electrocatalyst activity of CoFe LDH/NF, sulfurization was conducted using the hydrothermal method, while the phosphidation was performed through a chemical vapor deposition (CVD) technique. The CoFeS/NF and CoFeP/NF electrodes exhibited significantly higher electrocatalytic activity than CoFe LDH/NF electrode. The CoFeP/NF electrode with a specific surface area of 6.8 m2 g−1 had lower overpotentials of 120 and 236 mV for hydrogen (HER) and oxygen (OER) evolution reactions, respectively. Additionally, the CoFeP/NF electrode exhibited a low potential of 1.32 V vs. RHE at a current density of 10 mA cm−2 for urea oxidation reaction (UOR). The CoFeP/NF electrode demonstrated low overpotentials of 224 and 273 mV in a seawater solution for HER and OER, respectively. The density functional theory (DFT) calculations confirmed the experimental results in which the CoFeP/NF material had promising electrocatalytic activity for renewable energy applications. • CoFe LDH/nickel foam electrode was sulfurized and phosphorized for water splitting. • Sheet-like morphology of CoFeP and CoFeS materials was similar to CoFe LDH. • CoFeP/NF showed higher water splitting performance than the CoFeS/NF electrode. [ABSTRACT FROM AUTHOR]

Zinc–nickel coatings based on the zinc-enriched gamma phase exhibit the maximum corrosion resistance and form the basis of the production of highly electrocatalytically active nanoporous nickel by selective dissolution. The electrodeposition of Zn–Ni alloys is the most widely used method of their preparation which proceeds by the mechanism of anomalous codeposition, where the deposition rate of the electropositive component (nickel) is lower as compared with the electronegative component (zinc). To obtain coatings of the particular morphology, chemical and phase composition, it is necessary to know the kinetics of the cathodic deposition of Zn–Ni alloys in the stage of heterogeneous nucleation, which is the goal of this study. The kinetics of this process is studied in non-stirred ammonium chloride electrolytes using the methods of cyclic voltammetry and chronoamperometry. The mechanism of heterogeneous nucleation at the electrodeposition of zinc and nickel is determined using the approach proposed by Palomar-Pardavé et. al which takes into account the contributions to the total cathodic current made by the parallel reaction of hydrogen reduction and the electric double layer charging. The nucleation mechanism for zinc–nickel coatings is described using the model of Scharifker–Hills for the electrodeposition of binary alloys additionally modified by taking into account the experimentally determined dependence of the composition of zinc–nickel coatings on the time in the stage of cathodic nucleation of the deposit. Using the method of energy-dispersive X-ray spectroscopy, the anomalous character of the deposition of Zn–Ni coatings is confirmed, where the ratio of atomic fractions Ni/Zn turns out to be lower than the ratio of concentrations of ions Ni2+/Zn2+ in the electrolyte. It is found that both during the electrodeposition of zinc and nickel from their individual solutions and during their anomalous codeposition, the nucleation rate constant increases with an increase in the cathodic potential but in average does not exceed 3 s–1, which points to the predominantly progressive nucleation. The growth of the new phase, regardless of its chemical composition, is limited by the 3D-diffusion of zinc and nickel ions to the electrode surface. The nucleation site density depends weakly on the deposition potential, decreasing with the transition from zinc to nickel and zinc–nickel alloys. As expected, the contribution of the side reaction of hydrogen reduction is the maximum for nickel electrocrystallization and decreases with the transition to Zn–Ni alloys and zinc, increasing with an increase in the cathodic potential, in agreement with the values of current efficiency. [ABSTRACT FROM AUTHOR]

To investigate the separation of Ni(II) impurity and the refining of the electrolyte for magnesium electrolysis, the electrochemical behavior of the Ni(II) impurity in the MgCl2–KCl–NaCl melt at 973 K has been studied using several techniques, including cyclic voltammetry (CV), square wave voltammetry (SWV), and chronoamperometry (CA). Based on the analysis of the CV and SWV curves, it can be inferred that the reduction of Ni(II) in the MgCl2–KCl–NaCl melt at the tungsten electrode exhibits a quasi-reversible reaction. This reaction involves the transfer of a pair of electrons in a single step. The diffusion coefficient was determined at 973 K to be 3.84 × 10−5 cm2 s−1 through the semi-integral method, with the activation energy for diffusion was found to be 45.81 kJ mol−1. The reaction rate constant for the Ni(II) redox reaction was determined to be approximately 10−3 cm s−1 using the Nicholson method. This value suggests that the reaction fall within the quasi-reversible range, as defined by the Matsuda–Ayabe standard. The results obtained from the CA technique have demonstrated that the deposition of nickel on the tungsten electrode occurs through an instantaneous nucleation process, which is primarily controlled by diffusion. [ABSTRACT FROM AUTHOR]

We present a unique, one‐step, hydrothermal process to prepare nickel sulfide (Ni3S2) foam by a simple and direct conversion from nickel foam, which contributes both as a scaffold for the reaction and as reactant. The Ni3S2 foam exhibits remarkable mechanical stability, retaining the structural integrity of the foam and excellent crystallinity even after ultrasonication at 200 W for 30 mins. We document the transformation of the nickel foam template into a Ni3S2 foam, highlighting the role of synthesis duration on the phase evolution and unique morphology of Ni3S2. PXRD and SEM analyses reveal a complete transformation after 24 hours from the nickel foam to a pure Ni3S2 foam, which has a highly porous and interconnected ultra‐thin nanosheet architecture. This significantly enhances the surface area and provides many electrochemical reaction sites. In a three‐electrode cell, the capacity of the Ni3S2 foam electrode is 3.9 C cm−2 at 8 mA cm−2, which is higher than previous reports for Ni3S2. In a hybrid supercapacitor device, the Ni3S2 foam demonstrates significant increase in capacitance through 500 cycles and the capacitance plateaus after 2000 cycles. Even after 8500 continued charge‐discharge cycles, the device exhibits excellent cycle stability indicating improvement with age. [ABSTRACT FROM AUTHOR]

The anodic oxygen evolution reaction (OER) remains a bottleneck for electrocatalytic water splitting due to its sluggish kinetics and, thus, high overpotentials. This limits water electrolysis as a key technology for the generation of hydrogen as a sustainable alternative to fossil fuels. For alkaline water splitting, perovskite phases (ABO3) with earth‐abundant first‐row transition‐metals have emerged as a promising material class for OER electrocatalysts. Among these, LaNiO3 has been found to exhibit high intrinsic OER activity. To increase catalyst utilization, a high surface area of the catalyst is desirable and can be achieved by impregnation of porous templates. In this work, La–Ni‐based oxides were prepared via impregnation of activated carbon and subsequent heating, combining precursor calcination and template removal into one step. The phase structure of the samples is analyzed via powder X‐ray diffractometry, and the morphology is determined by scanning electron microscopy. The synergistic effect of B‐site mixing iron as well as A‐site mixing strontium into LaNiO3 is studied and found to increase its OER activity, confirming the activity‐enhancing effect of Fe in Ni‐based OER electrocatalysts. To allow for facile technical application of the catalysts, the electrodes are prepared by coating a perovskite ink onto Ni‐metal as industrially relevant substrates, followed by calcination. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Chemical Communications" published in 2024. It includes various articles on topics such as COF solid-state electrolytes for lithium batteries, supramolecular light-harvesting systems, functional surfactant-directing ultrathin metallic nanoarchitectures, recent advances in radical cyclization, and more. The journal is published by The Royal Society of Chemistry and focuses on exceptional research in the field of chemistry. [Extracted from the article]

Hydrated nickel hydroxides with partial aluminum substitution were synthesized using the conventional coprecipitation and soft chemistry methods. The soft chemistry derived sample showed better reversibility owing to the low activity for oxygen evolution during charging. Operando X-ray diffraction indicated the increased interlayer distance and decreased crystallinity during discharging caused by water accommodation. [ABSTRACT FROM AUTHOR]

Water electrocatalysis for hydrogen production as a prospect strategy to store renewable energy and reduce carbon emissions has attracted great attention, and exploring water electrolysis catalysts has become a research hotspot for widespread industrial water electrolysis application. Very recently, transition metal borates have been demonstrated great potential for electrocatalytic hydrogen or oxygen evolution in alkaline media. However, a generic method for fabricating transition metal borates as bifunctional oxygen catalysts are still challenging. Herein, through a two-step process including poly-aminophenylboronic acid electrodeposition and subsequent electrostatic self-assembly of transitional metal ions, for the first time, to our best knowledge, a simple and generic approach to fabricate polyaminophenylborate transition metal salt modified nickel foam electrodes (PAB-M/NF, M represents transition metal element) was developed for highly efficient water splitting. As a proof of concept, the obtained PAB-Ru/NF exhibited remarkable bifunctional HER and OER catalytic activities and stability in alkaline medium. To drive the HER and OER with a current density of 10 mA cm−2 in 1 M KOH electrolyte, PAB-Ru/NF only required an overpotential of 14 mV and 301 mV, respectively. Moreover, even at a great current density of 250 mA cm−2, PAB-Ru/NF can exhibit very favorable long-term stability for over 35 h. When assembled into an electrolyzer with PAB-Ru/NF as both the anode and cathode, a current density of 10 mA cm−2 can be achieved at a very low cell voltage of 1.50 V. In addition, the other PAB-M/NF catalysts (M including but not limited to Fe, Co and Ni) prepared by the same way also show excellent bifunctional HER and OER catalytic activities and durability. This study provides a prospective and economically feasible generic approach for developing practical bifunctional catalysts for industrial water electrolysis. For the first time, a simple and generic approach to fabricate polyaminophenylborate transition metal salt modified nickel foam electrodes (PAB-M/NF) was successfully developed through in-situ electropolymerization aminophenylboronic acid on NF electrode and subsequent electrostatic self-assembly between boric acid groups in polymer membranes and transition metal ions, and the as-resultant PAB-M/NF exhibited high-efficiency bifunctional catalytic performances for both the HER and OER, which highlights the promising application in industrial water electrolysis for hydrogen production. [Display omitted] • A generic method to fabricate polyaminophenylborate transition metal salt modified nickel foam electrodes. • A facile two-step process including in-situ electrodeposition and subsequent electrostatic self-assembly. • PAB-M/NF as excellent bifunctional catalysts for both the HER and OER. • Very favorable long-term stability even at a great current density of 250 mA cm−2. • Promising application in industrial water electrolysis for hydrogen production. [ABSTRACT FROM AUTHOR]

Electrocatalytic hydrogen evolution reaction (HER) via alkaline water splitting holds great promise for industrial clean hydrogen production but is frustrated by limited catalytic activity and inferior stability under high current density. Elaborate manipulating of heterostructure on robust catalytic electrodes is essential but challenging for accelerating HER kinetics with high durability. Herein, a robust nickel mesh electrode, offering high mechanical stability, is directly engineered with catalytic layers of multiple heterostructures (r‐Mn–Ni/CoP) via facile one‐pot electrodeposition followed by surface reconstruction strategy. The abundant heterostructures composed of crystalline CoP, NiP, amorphous region, and additional Mn doping considerably manipulate the electronic structure with optimized charge transfer; while the in situ surface‐reconstructed hydrophilic nanoflakes enable the rapid wetting of active sites to the electrolyte. Consequently, the r‐Mn–Ni/CoP requires only 134 mV overpotential at the current density of 100 mA cm−2, superior to monophasic and undoped samples, and the majority of reported HER catalysts. Remarkably, an electrolyzer with r‐Mn–Ni/CoP on a nickel mesh cathode demonstrates extraordinary activity with a voltage of 1.734 V at 300 mA cm−2 and stable operation of 800 h. The finding provides a feasible strategy for the fabrication of nonprecious‐metal‐based HER electrocatalysts with high activity and stability toward industrial water electrolysis. [ABSTRACT FROM AUTHOR]

Nickel/oxygen ion conducting ceramic composite powders (Ni/YSZ) are commonly used materials for fuel electrodes of solid oxide fuel cells and electrolyzers. One of the ways for increasing the activity of Ni/YSZ is infiltration/impregnation, where a formed porous electrode is impregnated with solutions of active elements, followed by thermolysis. In this study, Ni/YSZ electrodes simultaneously impregnated with nickel and ceria particles in different ratios are investigated. It is shown that the introduction of highly dispersed nickel only slightly increases the activity of the Ni/YSZ electrode and does not affect the pathway of the hydrogen oxidation reaction. If a minor amount of ceria particles is introduced into the electrode, it significantly increases its activity and partially changes the reaction mechanism. The best performance is obtained for the electrode impregnated with an equal volume solution of nickel and cerium nitrates. The polarization resistance of such an electrode in wet hydrogen is about 0.05 and 0.17 Ohm cm2 at 850 and 600 °C, respectively, which is about 10 and 65 times lower compared to initial Ni/YSZ. Long-term tests of more than 1100 h in a wet hydrogen atmosphere at 700 °C showed satisfactory stability of polarization resistance of all investigated electrodes. [Display omitted] • Ni/YSZ electrodes infiltrated with nickel and/or ceria were investigated. • The injection of nickel resulted in a negligible enhancement of Ni/YSZ activity. • Introduction of minor amounts of ceria leads to a partial change in HOR mechanism. • Introduction of close amounts of nickel and cerium is most effective. • Introduction of a significant amount of ceria completely changes the HOR mechanism. [ABSTRACT FROM AUTHOR]

In order to replace traditional hydrogen storage alloys and explore high-capacity anode electrode materials for nickel hydrogen battery (Ni-MH battery), amorphous Si (a-Si) thin films of different thicknesses were prepared using radio frequency (RF) sputtering deposition method, and pre-hydrogenated to prepare the a-Si:H thin films. The results indicate that the a-Si 40 thin film with a sputtering time of 40 min has high discharge capacity and good cycling stability. The discharge capacity of the a-Si 40 :H-5 thin film pre-hydrogenated at 300 °C, 5 MPa, and 3 h is up to 2026.42 mAh g−1, which is 2.43 times that of the a-Si 40 thin film (834.35 mAh g−1) and the rate performance has also been improved. Most H 2 are stored as Si–H bonds in a-Si 40 network structure after hydrogenation. When the H 2 exist in a free state or molecular form in the gaps of a-Si:H structures with high hydrogen concentration, this structure usually becomes a metastable structure with good conductivity, which is beneficial for the electrochemical reaction and rate performance of the electrode. This study provides ideas for the development of new Si-based electrode hydrogen storage materials for future high-energy density of Ni-MH battery. [Display omitted] • The use of a-Si thin film has improved the negative electrode capacity of Ni-MH battery. • The a-Si film with good discharge capacity and cycle stability were obtained by optimizing the preparation time by magnetron sputtering. • By optimizing hydrogenation time, temperature, and pressure, the electrochemical discharge capacity of a-Si thin film was further improved. [ABSTRACT FROM AUTHOR]

The urgent need for efficient oxygen evolution reaction (OER) catalysts has led to the development and publication of many heterostructured catalysts. The application of such catalysts with multiple phases tremendously increases the material design dimensions, and numerous interface‐related effects can tune the OER performance. In this regard, multiple of these heterostructured electrodes show remarkable OER activities. However, it is not clear if these carefully designed interfaces remain under prolonged OER conditions. Herein, a molecular approach is used to synthesize four different nickel‐iron phosphide (heterostructured) materials and deposit them on fluorine‐doped tin oxide and nickel foam electrodes. The OER performance of the eight electrodes and the reconstruction of the four materials is investigated by in‐situ spectroscopy after one day of operation, enabled by a freeze‐quench approach. The most active electrode is also applied under industrial OER conditions and for the value‐added oxidation of alcohols to ketones. Before catalysis, this electrode comprises crystalline 4 nm nickel phosphide particles on an amorphous iron phosphide matrix. However, after 24 h, a homogenous nickel‐iron oxyhydroxide phase has formed. This work questions to which extent the design of heterostructures is a suitable strategy for non‐noble metal OER catalysis. [ABSTRACT FROM AUTHOR]

Developing highly efficient and stable electrocatalysts for urea electro-oxidation reactions (UORs) will improve wastewater treatment and energy conversion. A low-cost cobalt sulfide-anchored nickel sulfide electrode (CoS/Ni3S2@CP) was synthesized by electrodeposition in DMSO solutions and found to be highly effective and long-lasting. The morphology and composition of catalyst surfaces were examined using comprehensive physicochemical and electrochemical characterization. Specifically, CoS/Ni3S2@CP electrodes require a potential of 1.52 volts for a 50 mA/cm2 current, confirming CoS in the heterointerface CoS/Ni3S2@CP catalyst. Further, the optimized CoS/Ni3S2@CP catalyst shows a decrease of 100 mV in the onset potential (1.32 VRHE) for UORs compared to bare Ni3S2@CP catalysts (1.42 VRHE), demonstrating much greater performance of UORs. As compared to Ni3S2@CP, CoS/Ni3S2@CP exhibits twofold greater UOR efficiency as a result of a larger electroactive surface area. The results obtained indicate that the synthetic CoS/Ni3S2@CP catalyst may be a favorable electrode material for managing urea-rich wastewater and generating H2. [ABSTRACT FROM AUTHOR]

Transition metal oxide–based pseudocapacitors with various valence states are of particular interest in the field of energy storage due to their increased specific capacitance values. In particular, Copper cobaltite nanomaterials have attracted more research focus due to their multiple oxidation states in comparison to other transition metals. Spinel structures of metal oxides are of tremendous interest for energy storage applications. Mixed valence metal cations in spinel cobaltites (MCo2O4) offer more electronic conductivity and electrochemical activity than single–component oxides. Natural abundance, good electrical and thermal stability, environment–friendly nature, and low cost motivates researchers for carrying out an extensive study of such materials. In this study, binary composite CuCo2O4@Co3O4 was synthesized by facile hydrothermal method. FT–IR, XRD, FEG–SEM and XPS studies have established the successful formation of all the nanocomposites were used to primarily characterize the sample. XRD showed the existence of all the synthesized materials in crystalline form. Cyclic voltammetry (CV), Galvanostatic Charge–Discharge (GCD) and Electrochemical Impedance (EIS) measurements were recorded to examine the electrochemical characteristics. The comparative specific capacitance of the synthesized CuCo2O4@Co3O4 nanocomposite displayed 542.77 Fg−1 using Glassy Carbon (GCE) as the working electrode whereas it exhibited 683.72 Fg−1 at the same current density of 1 Ag−1 using Nickel foam as the electrode substrate. The composite electrode exhibited an excellent pseudocapacitive behaviour using 1 M Na2SO4 and 1 M KOH as electrolytes respectively for electrochemical measurements. Impedance analysis reveals capacitive nature of the synthesized materials. Furthermore, cyclic stability for CuCo2O4@Co3O4 nanocomposite was found to be 76% (GCE) upto 1000 cycles at 5 Ag−1 and 78% (Nickel foam) upto 3000 cycles at 5 Ag−1. Based on the study of the electrochemical performance, the synthesized transition metal oxide nanocomposite holds potency as an efficient electrode material for energy storage applications. [ABSTRACT FROM AUTHOR]

Gluconic acid and sorbitol are among the value-added chemicals that can be derived from biomass. Nowadays, these compounds are typically produced through biotechnological processes, but electrochemical methods offer numerous advantages over alternative approaches. While studies have extensively explored metals like copper, palladium, gold, and platinum, nickel has received relatively limited attention in this context. Notably, nickel exhibits electrochemical activity suitable for organic electrosynthesis. This work has been achieved with 5-h long-term electrolysis, glucose as a reactant, utilizing modified nickel electrodes in a KOH solution. While these studies achieved substantial conversion rates, the selectivities and Faraday efficiencies toward gluconic acid and sorbitol remained comparatively low. The long-term electrolysis of glucose using modified nickel electrodes resulted in the identification of various side products. These include formic acid, oxalic acid, glycolic acid, tartronic acid, glyceric acid, and arabinose. [ABSTRACT FROM AUTHOR]

Previous studies have shown that partially coating electrode surfaces with patterns of 'islands' of hydrophobic tetrafluoroethylene (PTFE; Teflon) may lead to more energy efficient gas generation. This occurred because the gas bubbles formed preferentially on the PTFE, thereby freeing up the catalytically active metallic surfaces to produce the gas more efficiently. This work examined electrochemically induced hydrogen bubble formation on a nickel electrode surface that had been coated with linear patterns of PTFE. The impact of the PTFE line size (width) and degree of coverage was examined and analyzed. No improvement in electrical energy efficiency was observed up to 15 mA/cm2 when comparing the PTFE-coated electrodes with the control bare uncoated electrode. However, increasing PTFE coverage up to 15% generally improved electrolysis performance. Moreover, samples with 50% wider lines performed better (at the equivalent PTFE coverage), yielding an overpotential decline of up to 3.9% depending on the PTFE coverage. A 'bubble-scavenging' phenomenon was also observed, wherein bubbles present on the PTFE lines rapidly shrunk until they disappeared. [ABSTRACT FROM AUTHOR]

Battery-type hybrid supercapacitors (HSCs) (otherwise known as supercapatteries) are novel electrochemical energy storage devices bridge the gap between rechargeable batteries and traditional SCs. Herein, we report the synthesis of layered two-dimensional (2D) nickel disulfide (NiS2) nanosheets (NSNs) modified with poly(3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS) and their successful implementation in battery-type SCs. Initially, a layered 2D NSN is synthesized via a microwave-assisted hydrothermal method and further used as a template to coat PEDOT:PSS in order to prepare NiS2@PEDOT:PSS nanocomposite electrodes by a facile drop-casting method. This is the first-time report on the synthesis of a hierarchical NiS2@PEDOT:PSS nanocomposite electrode for battery-type HSC applications. An asymmetric battery-type HSC fabricated with NSN@PEDOT:PSS nanocomposite as positrode and activated carbon as negatrode delivers a maximum energy density of 52.1 Wh/kg at a current density of 1.6 A/g with a corresponding power density of 2500 W/kg. [ABSTRACT FROM AUTHOR]

The present work utilizes Direct Laser Interference Patterning (DLIP) to impart periodic microstructures onto the surface of nickel foils. A pulsed laser source emitting green radiation (514 nm) with pulse duration between 282 fs and 1 ps is utilized to produce line and cross-like pattern geometries having a spatial period of 3.0 µm and a maximum structure depth of ~ 2.8 µm. Both the pulse duration and number of consecutive scans are varied in order to assess their influence on the structure formation. Afterwards, the treated Ni- electrodes are used for alkaline water electrolysis. The most active electrode exhibits an overpotential of -227 mV at a current density of -0.5 A cm-2 for the Hydrogen Evolution Reaction (HER). Thus, the technique here proposed permitted a 51 % reduction in the overpotential of the HER compared to the untreated Ni-electrode, opening up possibilities for the development of more efficient electrodes for hydrogen production. [ABSTRACT FROM AUTHOR]

Metallic glasses (MGs) are a type of multicomponent non-crystalline metallic alloys obtained by rapid cooling, which possess several physical, mechanical, and chemical advantages against their crystalline counterparts. In this work, an Fe-based MG is explored as a hydrogen storage material, especially, due to the evidence in previous studies about the capability of some amorphous metals to store hydrogen. The evaluation of an Fe-based MG as a novel negative electrode material for nickel/metal hydride (Ni-MH) batteries was carried out through cyclic voltammetry and galvanostatic charge–discharge tests. A conventional LaNi5 electrode was also evaluated for comparative purposes. The electrochemical results obtained by cyclic voltammetry showed the formation of three peaks, which are associated with the formation of Fe oxides/oxyhydroxides and hydroxides. Cycling charge/discharge tests revealed activation of the MG electrode. The highest discharge capacity value was 173.88 mAh/g, but a decay in its capacity was observed after 25 cycles, contrary to the LaNi5, which presents an increment of the discharge capacity for all the current density values evaluated, reached its value maximum at 183 mAh/g. Characterization analyses performed by X-ray diffraction, Scanning Electron Microscopy and Raman Spectroscopy revealed the presence of corrosion products and porosity on the surface of the Fe-based MG electrodes. Overall, the Fe-based MG composition is potentially able to work as a negative electrode material, but degradation and little information about storage mechanisms means that it requires further investigation. [ABSTRACT FROM AUTHOR]

Azo dyes like methyl orange (MO) are very toxic components due to their recalcitrant properties which makes their removal from wastewater of textile industries a significant issue. The present study aimed to study their removal by utilizing aluminum and Ni foam (NiF) as anodes besides Fe foam electrodes as cathodes in an electrocoagulation (EC) system. Primary experiments were conducted using two Al anodes, two NiF anodes, or Al-NiF anodes to predict their advantages and drawbacks. It was concluded that the Al-NiF anodes were very effective in removing MO dye without long time of treatment or Ni leaching at in the case of adopting the Al-Al or NiF-NiF anodes, respectively. The structure and surface morphology of the NiF electrode were investigated by energy dispersive X-ray (EDX), and field emission scanning electron microscopy (FESEM). Response surface methodology was utilized to predict the optimum conditions by considering current density with 4-8 mA/cm² range, NaCl concentration in the range of 0.5-1 g/L, and electrolysis time of 10-30 min as controlling parameters. A very high MO dye removal percentage was achieved (97.74%) at 8 mA/cm², 1 g/L of NaCl within 30 min of electrolysis and consumed energy was 36.299 kWh/kg. This cost-effective EC system with the Al-NiF anodes besides Fe foam as cathode approved its high efficiency in removing MO dye with moderate amounts of NaCl due to the excellent 3D structure of these foam electrodes which highlight foam electrodes as an excellent choice for EC system in an environmentally friendly pathway. [ABSTRACT FROM AUTHOR]

This study explores a water‐splitting activity using a biphasic electrodeposited electrode on nickel foam (NF). The *Ni9S8/Cu7S4/NF electrode with citric acid reduction exhibits superior OER (oxygen evolution reaction) and HER (hydrogen evolution reaction) performance with reduced overpotential and a steeper Tafel slope. The *Ni9S8/Cu7S4/NF electrode displays the ultra‐low overpotential value of 212 mV for OER and 109 mV for HER at the current density of 10 mA cm−2. The Tafel slope of 25.4 mV dec−1 for OER and 108 mV dec−1 for HER was found from that electrode. The maximum electrochemical surface area (ECSA), lowest series resistance and lowest charge transfer resistance are found in citric acid reduced electrode, showing increased electrical conductivity and quick charge transfer kinetics. Remarkably, the *Ni9S8/Cu7S4/NF electrode demonstrated excellent stability for 80 hours in pure water splitting and 20 hours in seawater splitting. The synergistic effect of using bimetallic (Cu&Ni) sulfide and enhanced electrical conductivity of the electrode are caused by reduction of metal sulfide into metallic species resulting in improved water splitting performance. [ABSTRACT FROM AUTHOR]

This study introduces an electro-dehydrogenation method for converting amines into nitriles in aqueous environments, simultaneously releasing two moles of H2 using nickel electrodes. This eco-friendly process is selective and operates at room temperature, in contrast to traditional thermal methods that require high temperatures and where condensation products are usually observed. Detailed impedance spectroscopy analysis reveals that the dehydrogenation of amines in aqueous media is facilitated by efficient charge transfer, with the diffusion of amines to the electrode surface identified as the kinetically slowest step. Our study underscores the potential of electrochemistry to enhance the reversible dehydrogenation and hydrogenation of the amine/nitrile pair. By demonstrating the practicality and efficiency of this approach, we highlight the amine/nitrile pair as a promising candidate for liquid organic hydrogen carriers. This has significant implications for the future of hydrogen storage and transport technologies, paving the way for more sustainable and efficient energy solutions. [ABSTRACT FROM AUTHOR]

Two simple processes for enhancing liquid alkaline water electrolyzer performance are demonstrated. Both enhance 3D Ni electrodes by introducing a micron-scale rough structure throughout the bulk of the electrode. Oxidation/reduction relies on a simple thermal treatment cycle to create surface roughening through the volumetric expansion during NiO formation and volume contraction during reduction back to Ni metal. Catalyst infiltration introduces a washcoat of additional metal particles throughout the electrode, by flooding the electrode with catalyst precursor and converting it to micron-scale particles via a reducing thermal treatment. The largest improvement in performance (211 mV at 1.8 A cm−2) is observed for infiltrated NiFe-3x catalyst. For Fe-free Ni-only electrodes, oxidation/reduction provides a larger improvement (157 mV at 1.8 A cm−2) than infiltrated Ni-3X (106 mV at 1.8 A cm−2). For both processes, the observed electrode surface structure and performance is quite sensitive to the thermal treatment temperature. • Commercial Ni foam electrodes are enhanced for liquid alkaline electrolysis. • Oxidation roughens Ni and reduction introduces porosity, enhancing surface area. • Catalyst infiltration increases surface area throughout the bulk electrode. • Optimized thermal processing temperatures increase the impact of each approach. [ABSTRACT FROM AUTHOR]

[Display omitted] Binary metal phosphate electrodes have been widely studied for energy storage applications due to the synergistic effects of two different transition elements that able to provide better conductivity and stability. Herein, the battery-type binder-free nickel-manganese phosphate (NiMn-phosphate) electrodes were fabricated with different Ni:Mn precursor ratios via microwave-assisted hydrothermal technique for 5 min at 90 °C. Overall, NiMn3P electrode (Ni:Mn = 1:3) showed an outstanding electrochemical performance, displaying the highest specific (areal) capacity at 3 A/g of 1262.4 C/g (0.44 C/cm2), and the smallest charge transfer resistance of 108.8 Ω. The enhanced performance of NiMn3P electrode can be ascribed to the fully grown amorphous nature and small-sized flake and flower structures of NiMn3P electrode material on the nickel foam (NF) surface. This configuration offered a higher number of active sites and a larger exposed area, facilitating efficient electrochemical reactions with the electrolyte. Consequently, the NiMn3P//AC electrode combination was chosen to further investigate its performance in supercapattery. The NiMn3P//AC supercapattery exhibited remarkable energy density of 105.4 Wh/kg and excellent cyclic stability with 84.7% retention after 3000 cycles. These findings underscored the superior electrochemical performance of the battery-type binder-free NiMn3P electrode, and highlight its potential for enhancing the overall performance of supercapattery. [ABSTRACT FROM AUTHOR]

The quality of water is significantly impacted by the presence of Cr6+ and Ni2+ ions. This study investigates the effectiveness of a flow-by porous graphite electrode cell in removing these contaminants from simulated industrial wastewater. We explore the impact of various factors on the removal process, demonstrating the method's potential for efficient removal. The initial concentration of nickel and chromium ions (20 to 80 mg/l and 20 to 100 mg/l, respectively), the feed flow rate (0.28 to 1.11 ml/s), current density (0.2 to 2.25 mA/cm2) and pH all influence the removal rate and efficiency. A higher feed flow rate negatively affects the removal efficiency of both Ni2+ and Cr6+ ions. Nickel removal efficiency decreased by 34.9% at 20 ppm and 26% at 80 ppm, representing the highest and lowest reductions in efficiency, respectively. Chromium removal efficiency decreased by 19% at 100 ppm and 6.5% at 50 ppm, indicating the highest and lowest reductions in efficiency, respectively, under the same flow rate change. Under optimal conditions, the removal efficiency for Ni2+ was 99.47% after 15 min of operation at a current density of 1.96 mA/cm2, a flow rate of 0.28 ml/s, and a pH of 8 and the removal efficiency for Cr6+ was 99.97% after 10 min of operation at a current density of 2.25 mA/cm2, a flow rate of 0.28 ml/s, and a pH of 2. The flow-through porous electrode system achieves efficient heavy metal removal with operating costs of 0.24 USD/m3 for nickel and 0.38 USD/m3 for chromium at optimal conditions. [ABSTRACT FROM AUTHOR]

The nickel metal nanoparticles and 3D nitrogen-doped carbon matrix are adopted to embellish nickel oxide via a simplified hard template method. This strategy will shine the route to prepare and ameliorate the electrochemical performance of NiO-based electrodes and other-type electrodes for energy storage. [Display omitted] Tailoring the omnidirectional conductivity networks in nickel oxide-based electrodes is important for ensuring their long lifespan, stability, high capacity, and high-rate capability. In this study, nickel metal nanoparticles and a three-dimensional nitrogen-doped carbon matrix were used to embellish the nickel oxide composite NiO–Ni/N–C via simplified hard templating. When a porous nitrogen-doped carbon matrix is present, a rapid pathway would be established for charging and discharging the electrons and lithium ions in a lithium-ion battery, thereby alleviating the volumetric expansion of the NiO nanoparticles during the operation of the battery. Moreover, the Ni0 ions added to serve as active sites to improve the capacity of the NiO-based electrodes and strengthen their conductivities. The multielement-effects of the optimal NiO–Ni/N–C electrode leads it to exhibit a capacity of 1310.8 mAh g-1 at 0.1 A g-1 for 120 loops and a rate capability of 441.5 mAh g-1 at 20.0 A g-1. Kinetic analysis of the prepared electrodes proved their ultrafast ionic and electronic conductivities. This strategy of hard templating reduces the number of routes required for preparing different types of electrodes, including NiO-based electrodes, and improves their electrochemical performance to enable their use in energy storage applications. [ABSTRACT FROM AUTHOR]

Electrochemical catalysis emerges as a promising method for lignin depolymerization due to its environmental friendliness and mild reaction condition. Metal oxyhydroxides have displayed appealing electrochemical activity for the oxidation for various biomass substrates. In this study, we prepared different metal (Ni, Co, Mn, Fe, and Cu) oxyhydroxides on nickel foam electrodes through electrodeposition. Their electrochemical properties were characterized and the reactivity towards lignin oxidative cleavage was investigated using lignin model compounds. NiOOH exhibited significantly higher activity for oxidative cleavage of the β-O-4 linkage compared to other metal oxyhydroxides, resulting in a 93% yield of aromatic monomers with 99% selectivity towards benzoic acids. Furthermore, the reconstruction process of the active site NiOOH was revealed by in-situ testing, and the reaction mechanism was explored. The non-phenolic structure underwent Cβ–Cγ/Cβ–O or Cα–Cβ cleavage, predominantly producing benzoic acids, while the phenolic structure was rapidly oxidized into dicarboxylic acids over NiOOH. [ABSTRACT FROM AUTHOR]

This work presents studies to study the nucleation and growth mechanism of electrochemical NiMo films suitable for the decomposition reaction of water as an electrocatalyst, in which the value of the potential established from polarization measurements was maintained constant. Optimal conditions for the electrochemical synthesis of the Ni-Mo alloy on the surface of platinum and nickel electrodes were established using voltammetric studies examining the influence of many electrolysis parameters on the process of co-deposition of nickel with molybdenum. The chronoamperometric method provides more detailed information about the electrodeposition process by studying the nucleation and growth mechanism of electrochemical films in which the potential value determined from polarization measurements was kept constant. The curves were taken at various potential values -0.1, -0.2, -0.3, -0.4, -0.5, -0.6, -0.7, -0.8 and -0.9 V at room temperature. The study of these curves can be carried out by comparing the experimental calculated data with the equations of the Scharifker-Hills model. It was found that in the early stage, at potentials of -0.1 and -0.2 V, the experimental data fit into the curve of the progressive nucleation model, according to which Ni-Mo nucleation occurs on many active areas of the substrate surface, but at other potentials (from -0.3 to -0.9 V) deposition deviates towards instantaneous nucleation and growth. [ABSTRACT FROM AUTHOR]

The peels of pomegranate fruits were employed in the current work to produce activated carbon (AC) using the high temperature carbonization method. The generated activated carbon using pomegranate peel (AC-PP) powder was discovered to have a layered and porous form as revealed by scanning electron microscopic images. It was discovered that activated carbon had an energy gap (Eg) of 4.454 eV. The photocatalytic experiments performed for the degradation of fast blue dye reveal that after 120 min of UV light irradiation, the AC-PP powder achieve a decolorization rate of 62.9%, respectively. Current was collected through the nickel mesh, and the electrochemical elements in rGO, the principal active component in AC-PP powder, were supported by the mesh. Nickel mesh electrodes were analysed using impedance spectroscopy and cyclic voltammetry. Both AC-PP and AC-PP-rGO electrodes' hydrogen diffusion coefficients were determined to be 1.134 10–4 and 0.0014 cm2 s−1, respectively. Experiments with galvanostatic charge–discharge revealed the produced AC-PP and AC-PP-rGO electrodes' superior capacitance potential, which is useful in the fabrication of supercapacitors. The AC-PP and AC-PP-rGO electrodes have 175.6 and 324.8 F g−1 specific capacitances. These unique impacts can also be assessed by energy storage performance using affordable carbon resources in various applications. These novel results might be used for developing up particular resources for environmental and power storage applications. [ABSTRACT FROM AUTHOR]

The energy transition and the implementation of new electrochemical technologies will result in an increased reliance on critical raw materials for electrodes. Their large‐scale application will ultimately mean working with lower grade materials. Here we study the influence of metal impurities on nickel foam electrocatalysts. We do this by electrodepositing known amounts of first‐row transition metals (Cu, Cr, Mn, Fe, Co and Ni) on nickel foam and studying their performance in the oxygen evolution reaction (OER) as a model reaction. The electrodes' performance is studied using cyclic voltammetry (CV), linear sweep voltammetry (LSV), Tafel analysis, stepwise chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Combining these results with microscopy analysis, we show that even small amounts of transition‐metal impurities have profound effects on the catalytic performance of nickel electrodes. The changes affect the OER onset potential (the energy that the system requires to convert OH– to O2) and the Tafel slope of each electrode (the electrode's initial activity in the OER onset region). Our results highlight the implications of such impurities on electrode design and future large‐scale application. [ABSTRACT FROM AUTHOR]

Electrochemical oxidation is an energy-efficient and environmentally friendly reaction mode, but it is limited by the difficulty of fabricating electrode systems that can efficiently perform high-yield oxidation reactions at low potentials. Herein, we prepared V–N supported electrocatalysts with nickel foam as the electrode substrate (VO-N/NF nanocomposite) for electrocatalytic benzyl alcohol oxidation by a one-step hydrothermal method. Specifically, the VO-N/NF nanocomposite electrode can reach a current density of 100 mA cm−2 at a low voltage of 1.395 V (vs. RHE) in 1.0 M KOH electrolyte with only 0.2 mmol metal precursor. The synergistic effect of high-valent nickel-based compounds, as well as the exposed active sites resulting from the dissolution of V elements in the process, makes it super-efficient and profitable for electrocatalytic oxidation. The best proof is that the conversion, selectivity, and faradaic efficiency reach 99.7%, 99.5%, and 99.3%, respectively. Meanwhile, the electrode performance remains good after repeated reactions, with the conversion of benzyl alcohol and faradaic efficiency both being above 98.5%. The design of the electrode provides a new idea to broaden the range of organic reactions carried out by electrocatalysis. And it also helps to reduce the high overpotential caused by the original oxygen evolution reaction. [ABSTRACT FROM AUTHOR]

This article discusses the electrocatalytic synthesis of 1,2-dioxolanes from tetrasubstituted donor-acceptor cyclopropanes. The use of electrochemical activation allows for an alternative cleavage mode of C(sp3)-C(sp3) bonds, resulting in the formation of 1,2-dioxolanes. The study explores the optimization and reaction scope of this system, demonstrating the synthesis of 3,3,5,5-tetrasubstituted dioxolanes from various cyclopropanes. The proposed mechanism for this reaction is supported by previous studies on the electrochemical activation of donor-acceptor cyclopropanes. [Extracted from the article]

This work is the first corroboration of the synthesis, characterization, and advanced energy applications of the novel n-type Ga2O3–ZnO heaped nanorods (HNRs) via modified green route coupled microwave abetted synthesis. Upon nano-composite formation of this eco-friendly and sustainable material, there was a subsequent band gap tuning from 4.83 to 3.31 eV. Synthesized nanorods were characterized with the mixed monoclinic and hexagonal phase possessing average crystallite size of 52.51 nm. Ga2O3–ZnO HNRs sequined nickel foam electrode was assessed for energy generation in terms of the oxygen and hydrogen production. Green HNRs have greater propitiousness toward hydrogen generation with the lower overpotential and Tafel slope value of 127 mV and 117.9 mV dec−1. With the durability for 1500 min in electrolyte environment, the fabricated electrode excelled in reaching a charge storage capacity of 514 mAH g−1. In terms of the photoelectrical operation, Ga2O3–ZnO HNRs surpassed the pristine nanomaterials by effectively passivating the perovskite solar cells. Solar cell device comprised of the green HNRs as passivation agents achieved an efficiency of 16.19% and 1.04 V of the open circuit voltage (Voc). Synthesized nanomaterials have expressed sustainability and efficiency for advanced energy applications in a cost effective manner. [ABSTRACT FROM AUTHOR]

Supercapatteries are contemporary electrochemical energy‐storage devices that bridge the gap between the conventional supercapacitors and rechargeable batteries. Supercapatteries utilize battery‐type electrode‐active materials for their charge storage. Among the various futuristic materials, transition‐metal dichalcogenides receive prominent attention due to their excellent charge‐storage capabilities. Herein, the microwave‐assisted hydrothermal synthesis of layered two‐dimensional (2D) nickel sulfide nanosheets (NSN) and their application as electrode‐active materials in high‐performance asymmetric supercapatteries are reported. The layered 2D architecture is preferred for the electrode‐active materials as the layered electrode nanostructure provides a hindrance‐free movement to the electrolyte ions through it during the charge‐storage process that include intercalation/deintercalation mechanisms. The electrochemical thermal stability of the 2D NSN electrode reveals that its stability in KOH (aqueous) electrolyte is better than that in LiOH (aqueous) and NaOH (aqueous) electrolytes. The supercapattery electrode synthesized using 2D NSN exhibits excellent electrochemical charge‐storage performances bearing a maximum specific capacity of 594.77 C g−1 (an equivalent mass‐specific capacitance of 991.29 F g−1) in 2 M KOH (aqueous) electrolyte. The electrochemical cycling performance of the 2D NSN electrode shows a stability over 40 000 cycles without any significant capacity loss. An asymmetric supercapattery device fabricated with 2D NSN electrode as positrode and activated carbon as negatrode exhibits a maximum mass‐specific capacity of 143.58 C g−1 with a corresponding energy density of 29.91 Wh kg−1 in 2 M KOH (aqueous) electrolyte. [ABSTRACT FROM AUTHOR]

The 2D insulating material hexagonal boron nitride (h‐BN) has attracted much attention as the active medium in memristive devices due to its favorable physical properties, among others, a wide bandgap that enables a large switching window. Metal filament formation is frequently suggested for h‐BN devices as the resistive switching (RS) mechanism, usually supported by highly specialized methods like conductive atomic force microscopy (C‐AFM) or transmission electron microscopy (TEM). Here, the switching of multilayer hexagonal boron nitride (h‐BN) threshold memristors with two nickel (Ni) electrodes is investigated through their current conduction mechanisms. Both the high and the low resistance states are analyzed through temperature‐dependent current–voltage measurements. The formation and retraction of nickel filaments along boron defects in the h‐BN film as the resistive switching mechanism is proposed. The electrical data are corroborated with TEM analyses to establish temperature‐dependent current–voltage measurements as a valuable tool for the analysis of resistive switching phenomena in memristors made of 2D materials. The memristors exhibit a wide and tunable current operation range and low stand‐by currents, in line with the state of the art in h‐BN‐based threshold switches, a low cycle‐to‐cycle variability of 5%, and a large On/Off ratio of 107. [ABSTRACT FROM AUTHOR]

A self-developed iron-loaded activated carbon-based nickel foam electrode (Fe/AC/Ni cathode) was used to construct electro-Fenton reaction system to treat coking wastewater. To meet the gap between laboratory beaker experiments and field trials for practical applications, we proposed and validated a method for obtaining organic loads, the essential parameters used in the design of electrochemical systems for wastewater treatment. The three influencing factors most relevant to organic loading, the effective surface area of cathode, chemical oxygen demand (COD) concentration of influent, and treatment time, were selected and investigated for their effects on the COD removal rate of coking wastewater by single-factor experiments and further optimized by response surface method. The appropriate electrode area load (La) and reactor volume load (Lv) were calculated by their corresponding intrinsic relationships with the three factors. The optimum application conditions were effective surface area of cathode 28.5 cm2, COD concentration of influent 1.76 kg·m−3, and treatment time 160.43 min. Under these conditions, the maximum COD removal rate was 98.51%. The La and Lv were 8.905 mgCOD·cm−2·h−1 and 0.634 kgCOD·m−3·h−1, respectively. The characterization experiment results showed that the Fe/AC/Ni cathode had a significant effect on the treatment of refractory organic contaminants in coking wastewater. [ABSTRACT FROM AUTHOR]

Stable reference electrodes (REs) are crucial for reliable voltammetry, controlled potential electrosynthesis, or spectro‐electrochemistry. Yet, inferior pseudo‐REs, such as plain Ag wire are often used, because commercial REs are expensive, may degrade or contaminate under required conditions, or don't fit geometric restrictions of custom setups. Addressing such cases, we report construction, benchmarking and utilization of easy to make, cheap (<1 €), and robust miniature REs from pasteur pipettes, molecular sieve beads and Ag wire. Excellent potential precision and accuracy with at least 1 week device stability was obtained for aqueous Ag/AgCl REs with 3 M NaCl in H2O and anhydrous 0.1 M TBACl in MeCN inner‐electrolytes. Even in alkaline 1 M NaOH electrolyte, where initial Ag/AgCl REs quickly convert to Ag/Ag2O (1 M NaOH) REs, perfect potential precision, accuracy, and at least 1 week stability are demonstrated. According to experimental needs, miniature REs can be built with many organic and aqueous electrolytes. For these custom use‐cases, we report guidelines to calibrate absolute RE potential, and to assess device precision, accuracy and stability. Finally, electro‐hydrogenation of styrene on nickel electrodes exemplifies superiority of Ag/AgCl REs over Ag wire pseudo‐REs, affording more reliable electrolysis current, cell potential and potential dependent Faraday efficiency. [ABSTRACT FROM AUTHOR]

The impact of varying electrolytic solutions on the electrochemical performance of electrode substances is significant. Consequently, this research investigates the effects of different electrolytes on the performance of nickel pyrophosphate (Ni 2 P 2 O 7) electrodes in the context of supercapacitor applications. Nickel pyrophosphate electrodes were synthesized on nickel foam (NF) substrates using a facile, scalable chemical bath deposition (CBD) technique. The Ni 2 P 2 O 7 material characterized different physico-chemical comprehensive characterization. Electrochemical assessments of Ni 2 P 2 O 7 /NF electrode were conducted in 2 M solutions of KOH, NaOH, and LiOH. Notably, in a 2 M KOH milieu, Ni 2 P 2 O 7 exhibited a superior specific capacity of 156.3 mAh/g at 50 mA/cm2, alongside a cyclic retention rate of 71.6% after 5000th CV cycles. Additionally, it demonstrated enhanced energy (31.26 Wh/kg) and power densities (699 W/kg). Moreover, a Ni 2 P 2 O 7 /NF-based symmetrical solid-state energy storage device revealed a specific capacitance of 163.53 F/g, with energy and power densities of 7.25 Wh/kg and 125 W/kg, respectively, at a current density of 2 mA/cm2. This study highlighted the need to choose an appropriate electrolyte based on the electrode material. [Display omitted] • Monoclinic NPO/NF microstructure prepared by cost effective chemical bath deposition method. • NPO/NF micro-plates are well-separated for better penetration of alkaline electrolytes. • The influence of different alkaline electrolytes on the electrochemical properties of optimized NPO/NF is examined. • The synergetic effect between microplates and the electrolytes boosted the overall performance of NPO/NF. • Fabricated and evaluated the performance of a symmetric device which shows excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

Ni foam is an extensively used current collector and substrate in investigations of electrochemically active materials such as supercapacitors and electrocatalysts for oxygen and hydrogen evolution reactions. This material is relatively cheap, porous, and conductive and has a large specific surface area, all of which make it a good substrate. We investigated Ni-Mg ferrites and NiMn2O4 as active materials for electrochemical energy storage. These materials, when loaded on Ni foam, gave promising capacitance values: 172 F/g (at 2 mV/s) for NiMn2O4 in 6 M KOH and 242 F/g (at 2 mV/s) for MgFe2O4 in 3 M KOH. Nevertheless, during the authors' work, many experimental problems occurred. Inconsistencies in the results directed further investigation towards measuring the capacitance of the active materials using GCE and platinum electrodes as substrates to discover if Ni foam was the culprit of the inconsistencies. When non-nickel substrates were used, both NiMn2O4 and MgFe2O4 showed reduced capacitance. Experimental problems associated with the utilization of Ni foam as a substrate for active materials in supercapacitor electrodes are discussed here, combined with other problems already addressed in the scientific literature. [ABSTRACT FROM AUTHOR]