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The synthesis of abundant well-separated nanoparticles by electrodeposition is difficult since the electroplated nanoparticles tend to aggregate in their overlapping lateral diffusion zones. As a result, the facile electrodeposition method is rarely employed to prepare catalysts especially those for ammonia borane (AB) hydrolysis. Herein, well-separated amorphous CoFeNiP nanoparticles with a mean size less than 100 nm are obtained on Cu foams using galvanostatic electrodeposition. Remarkably, the glass-to-crystal structural transformation is activated in CoFeNiP after the first cycle of catalytic AB hydrolysis, accompanied by the changes in their morphology from monolithic nanoparticles to flower-like nano-ribbons with a characteristic size of ∼20 nm. The as-activated CoFeNiP alloy catalysts exhibit an enhancement in their performance of catalytic dehydrogenation of AB hydrolysis with a high turnover frequency of 12.5 min−1 at 303 K and a low apparent activation energy of 23.4 kJ mol−1, achieving ultrahigh durability after 5 cycles. The results demonstrate transition-metal phosphides could be used as practical noble-metal free alloy catalysts for hydrolytic dehydrogenation of AB with low cost, high performance and excellent recyclability. • Amorphous CoFeNiP (CFNP) alloy nanoparticles are successfully synthesized on Cu foam by electrodeposition. • The glass-to-crystal structural transformation is activated in the nanoparticles after the first cycle of catalytic ammonia borane (AB) hydrolysis. • The activated flower-like CFNP nano-ribbons with a characteristic size of ∼20 nm have enhanced TOF and durability. • Nano-flower CFNP alloys are ideal catalysts for hydrolytic dehydrogenation of AB with high performance. [ABSTRACT FROM AUTHOR]

This study focuses on the potentiostatic electrodeposition of copper indium and cadmium sulfide (CuS, In 2 S 3 , and CdS) thin films on copper substrates, aiming to develop efficient electrocatalysts for the electrochemical reduction of CO 2 and sustainable hydrogen generation. Utilizing Cu Kα radiation for X-ray diffraction (XRD) analysis, the crystal structures of the electrodeposited films were confirmed, revealing well-defined crystalline phases. The films exhibited average particle sizes of 55.99 nm for CuS, 50.37 nm for In 2 S 3 , and 63.51 nm for CdS. Cyclic voltammetry and chronoamperometry were employed to optimize the deposition parameters, ensuring efficient nucleation and growth of the metal sulfide films. The electrochemical performance of the synthesized electrocatalysts was rigorously tested, demonstrating their potential for CO 2 reduction under optimized conditions with the highest efficiency for CdS electrodes. Additionally, the electrodeposited CuS and CdS are of the p-type, and In 2 S 3 is of the n-type semiconductor were studied and verified by the Mott–Schottky test. CuS, In 2 S 3 , and CdS were found to have donor and acceptor concentrations (N D) of 1.68 × 106, 1.44 × 105, and 8.9 × 105 cm3, respectively. The photoelectrochemical measurements of the electrodeposited metal sulfides were studied at ambient temperature and under illumination, providing higher photocurrent responses for CdS and demonstrating its strong potential as a photoelectrode material for CO 2 reduction. This work underscores the significance of facile electrochemical synthesis methods in developing cost-effective and scalable electrocatalysts, paving the way for their integration into photoelectrochemical systems for green energy applications. [Display omitted] • Potentiostatic electrodeposition was used for CuS, In 2 S 3 , and CdS thin films. • XRD confirms high crystal phase purity and well-defined crystallinity. • Average particle sizes: CuS 55.99 nm, In 2 S 3 50.37 nm, CdS 63.51 nm. • CdS demonstrates the highest efficiency in electrocatalytic performance. • The study supports scalable, eco-friendly methods for CO 2 and H 2 applications. [ABSTRACT FROM AUTHOR]

This study investigates the development of Ni-Co/SiO 2 nanocomposite coatings on mild steel surface using pulsed-current electrodeposition method. The effects of incorporating SiO 2 nanoparticle and varying its concentration on the coatings' microstructure, microhardness, wear resistance, and frictional properties were assessed using field-emission electron microscopy, X-ray diffraction, Vickers microhardness testing, and dry sliding wear tests. The results indicated that the coatings exhibited two-phases of Ni-Co solid solution (α) with a face-centered cubic (FCC) crystal structure and hexagonal Co, a refined crystallite size of approximately 31 nm for Ni-Co and about 25 nm for Ni-Co/SiO 2 , along with a colony-like morphology that did not show any preferred growth direction. The amount of Ni-Co solid solution increased with the addition of SiO 2 nanoparticles. The composite coatings demonstrated enhanced microhardness of 581 HV, which is 52 % greater than that of the Ni-Co coating, as well as improved wear resistance and a reduced friction coefficient compared to the unreinforced alloy coating. However, higher SiO 2 content adversely impacted the tribological properties due to nanoparticle agglomeration. Analysis of the worn surfaces revealed a transition from abrasive wear to oxidative wear with increasing applied force for the coatings. [ABSTRACT FROM AUTHOR]

In the current work, CeO 2 nanoparticles were embedded in Ni-W alloy matrix by pulse electrochemical deposition on copper substrate to optimize their microstructure and corrosion resistance. The effects of CeO 2 concentration and deposition time on Ni-W/CeO 2 composite coating were investigated for optimized structure and improved corrosion resistance. The composite coatings present nodular-like surfaces with dense and compact growth profiles, containing 63.03–67.88 wt% Ni, 28.73–31.87 wt% W and 0.25–8.24 wt% Ce. The content of incorporated CeO 2 in coatings increased with the increase of CeO 2 concentration in electrolyte. The addition of CeO 2 particles has refined the grains of the prepared coating. The surface became rougher with the extension of electrodeposition time. Ni-W/CeO 2 composite coating electrodeposited at 10 g L−1 CeO 2 for 60 min possessed the highest corrosion resistance, indicating enhanced corrosion protection and long-term stability. This premium coating can be applied in harsh environments to prolong the lifespan of machinery, equipment, and parts in marine, vehicle, aerospace, and chemical industries. [ABSTRACT FROM AUTHOR]

This study presented the electrochemical deposition of potassium nitrate-doped polypyrrole (Ppy:KNO 3) on stainless steel (SS), graphite sheet (GRs), and carbon fiber (CF) substrates, Ppy:KNO 3 /SS, Ppy:KNO 3 /GRs, and Ppy:KNO 3 /CF supercapacitor electrodes. Structural, morphological, and molecular analyses were conducted using X-ray diffraction (XRD), scanning electronic microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). SEM images exhibited distinct morphologies of Ppy:KNO 3 films, varying with cycles, scan rates, and Ppy:KNO 3 concentrations. Ppy:KNO 3 /CF film displayed a unique structure with minimal particle aggregation. Electrochemical performance was assessed through Cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) measurements and electrochemical impedance spectroscopy (EIS). Notably, Ppy:KNO 3 /CF demonstrated a specific capacitance of 1020 F/g at 1 A/g. It exhibited 92 % capacitance retention after 1000 cycles, along with impressive power and energy densities of 310 W/kg and 71.2 Wh/kg, respectively. These results represented a significant progress in the development of high-performance, durable supercapacitors. [ABSTRACT FROM AUTHOR]

Hydrogen is a renewable and environmentally friendly energy carrier and is considered a viable alternative to fossil fuels. Consequently, developing electrodes with excellent hydrogen evolution electrocatalysis is a top priority in research. However, the use of flat electrodes as cathode substrates by most researchers limits the electrocatalytic active area of the prepared electrode. To address this issue, it is essential to prepare a micro-nano structure on a cathode substrate before electrodeposition. This study introduced a novel Ni nanocone/Grid electrode, obtained through a combined laser-electrodeposition process to investigate its electrocatalytic activity and stability for the hydrogen evolution reaction (HER). Various techniques, including linear sweep voltammetry (LSV), electrochemical impedance spectra (EIS), cyclic voltammetry (CV), and chronopotentiometry (CP) in 1 M KOH solution, were employed to assess the HER electrocatalytic performance of the Ni nanocone/Grid electrodes. The experimental results demonstrated that the electrodes could achieve current densities of -10, -20, and -100 mA/cm2 with corresponding overpotentials of -281, -308, and -390 mV, respectively. Additionally, the Tafel slope of these electrodes was found to be only -82.05 mV/dec. The enhanced catalytic performance of the electrode was attributed to the synergistic effect of the grid-like and nanocone structures, which significantly increased the electrocatalytically active area and improved surface hydrophilicity, thereby boosting electrocatalytic performance. The simplicity of the preparation method and the exceptional performance of the electrode provide a promising new avenue for future research on HER electrocatalysts. • A new laser-electrodeposition combined process was proposed to prepare the catalytic electrode for hydrogen evolution. • Ni nanocone/Grid showed low overpotential and Tafel slope for hydrogen evolution. • The combination of grid structure and nanocone can significantly increase the ECSA of the electrode. • The electrode shows excellent hydrophilicity and extraordinary durability. [ABSTRACT FROM AUTHOR]

The development of an efficient yet cost-effective non-precious electrocatalyst for the hydrogen evolution reaction (HER) in alkaline water and seawater systems remains a formidable obstacle to the large-scale production of hydrogen energy, stemming from the sluggish kinetics of electron transfer reactions during the HER process. In this article, an amorphous Co-P-W electrocatalyst on nickel foam is prepared using a brief cyclic voltammetry (CV) electrodeposition method. The optimized Co-P-W electrocatalyst exhibits excellent electrocatalytic performance for HER, which only requires overpotentials of 59 and 143 mV to achieve a current density of 10 mA cm−2 in alkaline water (1.0 M KOH) and alkaline seawater (1.0 M KOH + natural seawater), respectively, and remarkable stability and durability. The improved HER performance of the Co-P-W electrocatalyst is attributed to the introduction of W, which modulates the electronic structure of Co and P, optimizes the adsorption/dissociation of H 2 O, and reduces the charge transfer resistance of the Co-P electrocatalyst, thus improving the kinetics of the HER. Furthermore, the W-doping significantly enhances the hydrophilicity of the Co-P electrocatalyst, which favors rapid and thorough penetration of electrolytes into the electrocatalyst, facilitating the formation of a highly accessible reaction interface, ultimately resulting in excellent HER activity. Our findings demonstrate the feasibility of designing an efficient, durable, and scalable electrocatalyst to significantly boost HER efficiency for practical water electrolysis. [Display omitted] • Binder-free Co-P-W catalyst for electrocatalytic hydrogen production was developed via electrodeposition method. • The low η 10 in alkaline water and seawater were 59 and 143 mV, respectively. • Mo adjusts the electronic structure to optimize the adsorption/dissociation of H 2 O. • W doping increases the active area, enhances the conductivity and hydrophilicity, and greatly improves its intrinsic activity. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) presents a major challenge for water splitting due to its slow kinetics. In this study, Co-Fe-Gr nanocomposite coatings were developed on carbon steel via electrodeposition using graphene (Gr) at concentrations of 0.02, 0.04, and 0.06 g/L to enhance OER performance. The sample with 0.02 g/L Gr exhibited a unique cauliflower-like morphology with aligned cobalt, as revealed by FE-SEM, leading to an increased electrochemical surface area. This optimal nanocomposite (Co-Fe-Gr (0.02 g/L)) demonstrated a low overpotential of 88 mV at 10 mA cm2, high stability (4.2 mF cm⁻2), and low resistance (R = 7.5 Ω cm⁻2). Additionally, it showed a small Tafel slope of 6.6 mV/dec and maintained stability after 12 h. A turnover frequency (TOF) of 73.6 s⁻1 indicated that graphene doping significantly reduced the adsorption energy of intermediates, greatly enhancing OER activity for efficient water splitting applications. [Display omitted] • Co-Fe-Gr nano-composite electrocatalysts were fabricated using an electrodeposition process. • Increasing the Gr content increased the Gr sheets and reduced the number of active sites. • The Co-Fe-Gr (0.02 g/L) with cauliflower-like morphology had an electrochemically active surface. • The Co-Fe-Gr (0.02 g/L) nano-composite showed the highest electrocatalytic activity. [ABSTRACT FROM AUTHOR]

This study reports a unique flow-through electrode design for hydrogen production in alkaline water electrolysis. This paper investigates a variety of electrodeposition coatings on the 3D-printed electrodes, including nickel, nickel-copper, and nickel-iron. The catalytic activity and properties of the electrodes are examined through electrochemical measurements involving linear sweep voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy, and surface morphology analysis. An experimental setup is also developed to measure hydrogen production and evaluate the efficiency of the designed electrodes. The study finds the flow-through electrodes coated with nickel-copper and nickel-iron achieve the current densities of 54 mA/cm2 and 45 mA/cm2, respectively. The activation overpotentials for the nickel-copper coated electrode are reported as 539 mV, and 408 mV for the nickel-iron coated electrode, both at a current density of 10 mA/cm2. The highest production rate is obtained within the first 15 minutes, 0.273 μg/s for the Ni-Cu flow-through electrode and 0.255 μg/s for the Ni-Fe flow-through electrode. The study further shows that flow-through electrodes produce hydrogen with an efficiency approximately 74% higher than traditional electrodes, suggesting a potentially better design for better hydrogen production in industrial applications. • This study reports a new flow-through electrode design for hydrogen production. • The electrodes are fabricated using 3D-printing and coated using electrodeposition. • The performance is evaluated using electrochemical and hydrogen measurements. • The study finds that flow-through electrodes perform better than traditional. • The flow-through electrodes consume less energy with the same or higher production. [ABSTRACT FROM AUTHOR]

Rational design of high-efficiency, durable and cost-effective electrocatalysts for H 2 production is essential to accelerate hydrogen production from fundamental experiments to practical industrial applications. Herein, cobalt-nickel-iron phosphides are constructed on Ni foam (CoNiFeP@NF) via a simple one-step electrochemical deposition method as self-supported electrodes for efficiently water splitting. The introduction of Fe element significantly enhances the catalytic properties of CoNiP@NF electrode for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Additionally, the optimal HER and OER electrodes are obtained by adjusting the Fe3+ concentration at 0.1 (CoNiFeP@NF-0.1) and 0.15 M (CoNiFeP@NF-0.15), respectively. Benefiting from the modulation of the electronic structure of CoNiP by the Fe element, CoNiFeP@NF-0.1 and CoNiFeP@NF-0.15 electrodes only require the overpotentials (η) of 48 mV for HER and 223 mV for OER to reach the current density of 10 mA cm−2, superior to the reference CoNiP@NF electrode (η 10, HER = 89 mV, η 10, OER = 333 mV). Subsequently, the electrolyzer constructed by CoNiFeP@NF-0.1 as cathode and CoNiFeP@NF-0.15 as anode exhibits excellent overall water splitting performance with a cell voltage of 1.56 V at a current density of 10 mA cm−2. This work provides a convenient and effective strategy for regulating the catalytic activity of bifunctional phosphide catalysts for water splitting. [Display omitted] • The cobalt-nickel-iron phosphides are successfully constructed on Ni foam via electrodeposition. • The catalytic activity can be optimized with the Fe3+ concentration. • CoNiFeP-0.1@NF presents a low overpotential (η 10 = 48 mV) toward HER. • CoNiFeP-0.15@NF presents a low overpotential (η 10 = 223 mV) toward OER. • CoNiFeP-0.15@NF displays excellent durability for OER. [ABSTRACT FROM AUTHOR]

The electrolysis of water is the key method for hydrogen production but the high overpotential necessitates electrocatalysts. Traditionally, Pt is used, but it is scarce and costly. Herein, MnCO 3 is unveiled as an electrocatalyst for the production of hydrogen. MnCO 3 is electrodeposited onto pencil graphite by chronoamperometric method and confirmed by XRD and vibrational spectroscopic studies. MnCO 3 electrodeposited for 15 min at 2 V demonstrates a good HER activity (overpotential of 123 mV to reach 10 mA cm−2) in 0.5 M H 2 SO 4 with a Tafel slope of 79 mV dec−1. In addition, MnCO 3 exhibited good stability during continuous operation (over 3000 cycles and 14 h). Though MnCO 3 requires higher overpotential than the benchmark catalyst (Pt/C) to reach 10 mA cm−2, it outperforms Pt/C at higher current density (≥75 mA cm−2) demonstrating that MnCO 3 could be used as an electrocatalyst to produce H 2 at a high rate from acidic medium. [Display omitted] • MnCO 3 is electrodeposited onto pencil graphite by chronoamperometry method. • MnCO 3 electrodeposited at 2 V demonstrates a good HER activity in 0.5 M H 2 SO 4. • MnCO 3 exhibits good stability (over 3000 cycles and 14 h of continuous operation). • MnCO 3 surpassed the performance of Pt/C at 100 and 200 mA cm−2 [ABSTRACT FROM AUTHOR]

Pd nanoparticles (PdNPs) are deposited electrochemically on the glassy carbon electrode surface using PdCl 2 dissolved in a deep eutectic solvent composed of choline chloride and urea (reline). The morphology and particle size of the PdNPs are determined from SEM exhibiting a homogeneous distribution with potential deposition depending on particle size. The particles display a core-shell morphology, consisting of Pd(0) as the core and Pd(OH) 2 as the shell. The ethanol oxidation reaction, EOR, is evaluated at different KOH concentrations. The electrocatalyst with the highest mass activity is achieved at −750 mV potential deposition and 1 M KOH, exhibiting 3126 ± 606 mAmg Pd −1. However, when 0.1 M KOH is used the mass activity decreases to one-third the value obtained at 1 M KOH. Notwithstanding, the mass activity displayed by these PdNPs is superior to that reported for other Pd-based nanoparticles synthesized using more complex, time-consuming and costly methods reported in the literature. [Display omitted] • PdNPs were prepared by electrodeposition method using reline as DES. • The morphology of the electrodeposited PdNPs is core-shell Pd@Pd(OH) 2. • PdNPs electrodeposited at −750 mV was the best MA for EOR using 1 M KOH. • Different KOH concentrations were employed to evaluate the EOR. • The optimal concentration of KOH in the EOR was 1 M followed by 0.5 and 0.1 M. [ABSTRACT FROM AUTHOR]

Designing and preparing an efficient bifunctional catalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial for achieving electrochemical water splitting. Constructing amorphous/crystalline heterojunctions catalysts are considered an effective method to enhance bifunctional catalytic activity, In this work, we developed an interfacial engineering strategy to prepare a three-dimensional amorphous NiFe layered double hydroxide/crystalline CoMo bimetallic phosphide heterojunction bifunctional composite material NiFe-LDH@CoMo–P on nickel foam using a simple and efficient electrodeposition method. Combining the crystalline CoMo–P for enhanced HER catalytic activity with the amorphous NiFe-LDH for superior OER catalytic activity ensures the bifunctional catalytic performance. Moreover, the formation of unique amorphous/crystalline heterointerfaces accelerates electron transfer, inducing electron rearrangement at the interface and resulting in more suitable Gibbs adsorption energies for catalytic reaction intermediates. This significantly enhances the catalytic reaction kinetics and improves the electrocatalytic activity. Density functional theory (DFT) calculations and experimental studies have shown that the d-band center of the active sites in NiFe-LDH@CoMo–P catalyst shifts towards the Fermi level, thereby optimizing the adsorption strength of catalytic reaction intermediates on the catalyst surface. In 1 M KOH, as a bifunctional catalyst, NiFe-LDH@CoMo–P/NF requires an anodic overpotential of 236 mV to achieve an OER current density of 20 mA cm−2, and a cathodic overpotential of −49 mV to achieve a HER current density of −10 mA cm−2. The study provides a new approach for the efficient and low-cost preparation of amorphous/crystalline heterojunction bifunctional catalysts. [Display omitted] • The heterogeneous interface was formed by coupling amorphous NiFe-LDH with crystalline CoMo bimetallic phosphide through a simple and efficient electrochemical deposition method. • The active area and electrical conductivity of the material were increased by building 3D porous catalyst directly on 3D nickel foam substrate. • The prepared composite catalyst material NiFe-LDH@CoMo–P/NF exhibits excellent bifunctional catalytic activity. [ABSTRACT FROM AUTHOR]

In electrocatalytic applications, catalyst interface crucially influences electrochemical activity and selectivity, balancing adsorption, desorption, and transport of intermediates and electrons. Capitalizing on this fact, this study unveils a novel approach to enhance CoO x surfaces, a promising electrocatalyst for water oxidation, through organic shell functionalization via electrodeposition. Utilizing a dinuclear cobalt complex 1 , resembling CoO x 's structure, we crafted a modified film exhibiting remarkable stability. This film consistently delivered a current density of 2.0 mA/cm2 for oxygen evolution at 1.5 V vs. NHE, sustaining over 25 h under neutral conditions with only a minimal 5% activity reduction. Conversely, the standard CoPi catalyst underwent rapid deterioration, losing about 40% of its initial catalytic current in just 14 h. Further investigations revealed that the organic shell effectively reduces catalyst dissolution, in contrast to the severe dissolution of CoPi, directly impacting its catalytic activity. This approach offers a straightforward means to functionalize various nanostructured materials, potentially enhancing their electrochemical activities and stabilities. [Display omitted] • Interface engineering of electrocatalysts with an organic ligand shell. • Mod-CoPi was electrodeposited from a dinuclear cobalt complex with a polyhydroxy ligand. • The mod-CoPi shows remarkable stability, maintaining over 90% activity for 50 h. • The unmodified CoPi degrades, losing 40% catalytic current in 14 h. • Analyses reveal CoPi dissolution key factor to its activity degradation. [ABSTRACT FROM AUTHOR]

The design and fabrication of active and stable nanostructured electrocatalysts for hydrogen production from the electrochemical water splitting is one of the most important strategies for economical hydrogen production and replacement fossil fuels. Using of Ni-based nanostructured alloy electrodes, synthesized via electrodeposition method, due to having a high active surface area, being binder-free, and also the synergistic effect between the alloy elements, can significantly reduce the energy consumption during hydrogen production. Due to the importance of alloy electrodes and the lack of a comprehensive review in this field, in this review article, at first, the advantages and brief mechanism of the electrodeposition method for the synthesis of nanostructured electrodes are given, and then the types of alloy systems and the resulting morphologies are reviewed. Finally, recent developments in the field of alloy systems for hydrogen production are summarized. Moreover, various methods of creating different alloy nanostructures with electrodeposition method are also described in this article. The purpose of this article is to create a deep understanding of the application of alloy nanostructures and to provide a guide for the synthesis of active and stable electrodes for hydrogen production. In addition, using this review paper, one can able to select appropriate alloy system for reaching the best electrocatalytic properties. • Different modes of electrodeposition mechanisms was reviewed. • Electrodeposited metallic nanostructures have favorable electrocatalytic activity. • Various morphologies can be fabricated via electrodeposition process. • Advantages of electrodeposition process over other methods was highlighted. [ABSTRACT FROM AUTHOR]

The electrodeposition process and the subsequent assessment of a novel cuprous oxide photocathode are conducted for solar light-based hydrogen production. The mesh dome photocathode helps facilitate the optimal light harvesting, enabling the efficient collection of the maximum accessible light from the solar simulator. This particular design also ensures that light reaches the remote surfaces of the photocathode through penetrating the mesh structure. The electrodeposition method is then employed to coat cuprous oxide onto the stainless-steel electrode. The subsequent examination of this photocathode occurs within an alkaline solution of potassium dioxide to assess its performance in hydrogen production. The study investigates the impact of the new design of the mesh photocathode on hydrogen generation rates, as well as related efficiencies of energy and exergy, under varying light angles during daylight hours. The present experimental findings reveal that the maximum rates of hydrogen production, achieved at a 45° tilt light and 0.25 M KOH, are 15.38 μg/s and it is 15.83 μg/s for vertical light positions. Furthermore, the highest recorded system exergy and energy efficiencies under vertical light conditions are 2.19% and 3.20%, respectively, compared to 2.14% and 3.12% at applying tilted light. The new photocathode design contributes to a notable 80.3% improvement in hydrogen generation rate at tilted light angles in comparison to vertical light conditions. • A novel PEC Cell Design with a unique photocathode is studied experimentally. • Hydrogen generation rates are estimated for the light of 45° and 90° orientation. • Exergy and energy efficiencies of the photoelectrochemical cell are assessed. • The current hydrogen apparatus accomplishes promising hydrogen generation results. [ABSTRACT FROM AUTHOR]

A composite coating of Ni–W–Ti 2 AlC was fabricated through direct current electrodeposition. The characterization of the composite coatings included analysis using X-ray diffractometry, scanning electron microscope, energy spectrum analysis, Vickers microhardness testing, electrochemical testing, and tribological testing. The findings indicate that the inclusion of Ti 2 AlC alters both the grain size and microstructure of the coatings. The presence of Ti 2 AlC particles facilitates the nucleation process during Ni–W–Ti 2 AlC deposition. The Ti 2 AlC content influences the coating's performance in the bath. Specifically, the microhardness of the Ni–W-(5 g/L) Ti 2 AlC coating exhibits the highest value, experiencing a 41.89 % increase compared to that of the Ni–W coating. Ti 2 AlC contributes to the rectification of defects in the Ni–W–Ti 2 AlC coating. This composite coating exhibits the lowest corrosion current and superior corrosion resistance, particularly with a Ti 2 AlC concentration of 5 g/L. The wear mechanism of the coating encompasses abrasive wear, adhesive wear, and oxidation wear. Notably, the Ni–W–Ti 2 AlC composite coating demonstrates enhanced friction resistance compared to the Ni–W composite coating. Incorporating Ti 2 AlC introduces a novel approach and avenue for fabricating high-performance tungsten-based functional coatings. [ABSTRACT FROM AUTHOR]

Modulating the heterojunction interface is an effective way to improve the electrocatalytic efficiency of water electrolysis, and the metal centers with preferred crystal plane orientation offer the potential to enhance the interfacial charge transfer and electrode reaction kinetics. In this study, a Co/CoP modified hydrogen evolution electrode with selective exposure of the metal-centered Co(002) crystal face was prepared using a one-step electrodeposition method by adjusting the P/Co molar ratio. Results demonstrate that the preferential orientation of Co(002) crystal face in Co/CoP leads to an increased electrochemical active surface area, significantly reduced interfacial impedance and Tafel slope. Moreover, it brings the d-band center closer to the Fermi level, which is thermodynamically favorable for hydrogen evolution reaction (HER). Under optimized conditions, Co/CoP exhibits overpotentials of 85 mV and 183 mV at 10 mA cm−2 and 100 mA cm−2, respectively. After long-term and cyclic stability tests, no significant activity decay is observed, demonstrating excellent hydrogen evolution activity and cyclic stability. [Display omitted] • The Co/CoP heterojuncions exposed Co(002) crystal face were prepared. • Interfacial charge transfer and kinetics of Co(002)/CoP for HER were accelerated. • The η 10 and η 100 of Co(002)/CoP was 85 mV and 183 mV, respectively. • DFT certified that the Co(002)/CoP had suitable energy barriers and d-band center. [ABSTRACT FROM AUTHOR]

Bi-unsupported films were fabricated via the electrochemical deposition method at different values of current density in two technological regimes: galvanostatic (GSR) and pulse (PR). It was observed that the unsupported Bi films obtained in GSR exhibited a granular structure. With increasing current density from 10 to 20 mA/cm2, there is a rise in the Bi grains' size, possibly due to their coalescence. In contrast, the films produced in the PR regime exhibit a fine-grained structure. The chemical composition study demonstrated that there are no interfering phases in the obtained films. Statistical analysis of the most probable grain size showed that the unsupported Bi films' grain size varied from 10.5 to 14.8 μm with increasing current density for the GSR. The grain size of the films received in the PR is 4.5 μm. The relation between the Bi-unsupported films' synthesis regimes and the crystal structure is determined. It has been shown that the presence of crystallographic texture correlates with scanning electron microscopy results. Due to the fact that the information about pure Bi-unsupported films obtained via pulse electrodeposition is almost absent in the literature, this study will increase awareness on this topic. The gamma-radiation shielding effectiveness was determined using Phy-X/PSD software and a Co60 gamma-quanta source. As a result of the comparison of the obtained parameters, a slight discrepancy between them and Pb was found. Due to the high toxicity of Pb, Bi-based materials with environmentally friendly properties may represent an outstanding choice for use as perspective materials for radiation shielding applications. [ABSTRACT FROM AUTHOR]

The design of low-price and flexible hydrogen evolution reaction (HER) electrode has attracted much attention on efficient utilization of sustainable hydrogen energy. Herein, we reported a facile fabrication of flexible HER electrode by anchoring CoP electrocatalyst on polyester (PET) textiles. Conductive nickel cloth (NC-PET) substrate was firstly obtained by sequentially electroless plating and electroplating of metallic Ni on textile fibers. The amorphous CoP catalyst was then assembled on the NC-PET substrate by controlled electrodeposition to obtain flexible HER electrode (CoP-NC/PET). The flexible CoP-NC/PET showed a low overpotential of 63 mV at 10 mA cm−2 for HER, with a Tafel slope of 48.09 mV dec−1 in 1 M KOH solution. The faradaic efficiency of CoP-NC/PET measured at 100 mA cm−2 current density was estimated to be nearly 100%. No significant loss of HER catalytic activity was observed after 2000 cycles and 1000 times folding operations, demonstrating the high flexibility and stability of the present CoP-NC/PET electrode. [Display omitted] • HER electrode was facilely fabricated by anchoring CoP on textiles. • Amorphous CoP electrocatalyst was obtained by electrodeposition. • Exhibited excellent HER activity and flexibility. [ABSTRACT FROM AUTHOR]

Ni thin films were synthesized through the electrodeposition method from three different electrolytes in absence and presence of the magnetic field. They were assessed as electrocatalysts for hydrogen evolution reaction (HER). Herein, we have studied the difference of the electrocatalytic activity of the fabricated materials towards HER in case of using them as fresh samples after the deposition process directly and after keeping them in boxes for 3 weeks (old samples). Moreover, we have studied the changes of the contact angle in case of the fresh and old samples. The old fabricated Ni films from the three electrolytes have shown higher catalytic performance. Moreover, the old and fresh fabricated Ni thin film from citrate has the smallest overpotential value of 234 mV and 288 mV, respectively in comparing with other films. The scanning electron microscope, X-Ray, Atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS) were used for films characterization. [Display omitted] • Different morphologies of Ni films depends on the changing of the electrolyte and magnetic field. • Old samples gives higher catalytic performance towards HER. • The more hydrophobic properties of the surface, the more its catalytic activity towards HER. • The deposited film from citrate under the magnetic field possesses the highest kinetics to HER. [ABSTRACT FROM AUTHOR]

A new catalytic combustion hydrogen (H 2) sensor is developed using the electrodeposition method and the Pd catalyst layer is directly deposited on a Pt filament without carrier. The sensing performance was investigated by altering the electroplating time to control the thickness of the Pd catalyst layer. The sensitivity is changed with the increase of the Pd layer's thickness and the highest sensitivity (26.8) was obtained when the thickness is 1.635 μm. In addition, the new sensor exhibits great selectivity, while having the advantages of low power consumption (25 mW) and high vibration resistance. The achievement of this carrier-free sensor is expected to meet the requirement for H 2 energy vehicles. • A carrier-free catalytic combustion H 2 sensor has been fabricated using the electrodeposition method. • The influence of catalytic layer on sensing performance was discussed. • The vibration resistance of sensors was demonstrated. [ABSTRACT FROM AUTHOR]

Affordable and sustainable hydrogen production is the need of the hour owing to the mounting global pursuit for the hydrogen economy. Water splitting is the premier go-to method to produce green hydrogen at a larger scale in which the half-cell Oxygen Evolution Reaction (OER) demands a larger amount of energy expenditure due to its sluggish kinetics. Hence, designing an efficient OER electrocatalyst, especially for alkaline water electrolysis that offers alternatives to the usage of precious group metals is a pressing priority. Herein, we report a novel nanocrystalline electrocatalyst consisting of two components, namely cobalt nickel phosphate and iron diselenide synthesised via a two-step electrodeposition at room temperature. The combination of the two components on the porous nickel foam substrate exhibits an overpotential of 272 mV at 100 mA/cm2 in 1 M KOH showing a low Tafel slope of a mere 38 mV/dec with appreciable retention even after 24 h of stability test at a relatively higher current density. The surface reconstruction that occurs when FeSe 2 is electrodeposited on (Ni 0.35 Co 0.65) 3 (PO 4) 2 @NF and the synergy between the two components is the primary reason for the improved performance. Thus, this work highlights the ambient synthesis of a highly durable earth-abundant metal-based electrocatalyst which exceeds the performance of the standard Ru/C by a decent margin. [Display omitted] • Nanocrystalline electrocatalyst (Ni x Co (1-x)) 3 (PO 4) 2 @FeSe 2 /NF is designed using ambient two-step electrodeposition. • The electrocatalyst shows an OER overpotential of 272 mV at 100 mA/cm2 with lower Tafel slope of 38 mV/dec. • The catalyst shows decent stability at a higher current density of 100 mA/cm2 with 99 % retention rate. • Synergistic effect between the two components results in the improved performance of the catalyst. [ABSTRACT FROM AUTHOR]

Effort to find efficient catalysts for the hydrogen evolution reaction (HER) continue due to the high cost and scarcity of Pt catalyst. This study centers on electrodeposited CoMoP, a transition metal-based catalyst, with a focus on augmenting its active sites. The Cu nanowires serve as a template, not only expanding the surface area of CoMoP but also aiding in electron acceptance due to their excellent electrical conductivity. Consequently, the surface area experiences an approximate 2.1-fold increase compared to the case without nanowires. Furthermore, the CoMoP on Cu nanowires exhibits a heterostructure with crystalline and amorphous phases, enhancing electrical conductivity and exposing active sites. This distinctive configuration facilitates the transfer of protons and electrons, thereby improving the electrocatalytic activity. As a result of this enhanced activity, the catalyst demonstrates fairly low overpotentials for HER in both alkaline and acidic conditions. At current densities of 10 and 100 mA cm−2 in alkaline environment, it only needs 32 and 117 mV, respectively. Similarly, in acidic environment, the overpotentials are 55 and 112 mV at 10 and 100 mA cm−2, respectively. The catalyst also shows good stability under both conditions. [Display omitted] • To increase surface area, Cu foam with Cu nanowires served as the substrate. • Heterostructure CoMoP catalyst was electrodeposited on the substrate. • The CoMoP catalyst underwent HER testing in acidic and alkaline conditions. • The CoMoP catalyst showed high HER activity and stability in both conditions. [ABSTRACT FROM AUTHOR]

Bimetallic transition metal oxides (CoMn 2 O 4) were prepared on conductive three-dimensional nickel foam through simple hydrothermal and air calcination methods. Then, a Co–CoMn 2 O 4 /Ni foam electrode was successfully prepared by anchoring Co on the CoMn 2 O 4 using constant potential electrodeposition method. The addition of Co metal enhanced the conductivity of the electrode, and the three-dimensional structure of CoMn 2 O 4 made the distribution of Co nanoparticles effectively dispersed, which was conducive to the full contact between Co metal particles and the electrolyte. In addition, the electronegativity difference between Co and Mn could also improve the performance of the prepared electrode, whose structure and composition were studied using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, surface area measurement and transmission electron microscopy, with its electrochemical behavior characterized using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. The results indicated that the Co–CoMn 2 O 4 /Ni foam electrode showed the best catalytic activity in 3 mol L−1 NaOH and 0.5 mol L−1 H 2 O 2 after 30min of Co electrodeposition. • Co–CoMn 2 O 4 /Ni foam electrode was successfully prepared by anchoring Co on the CoMn 2 O 4 nanoclusters. • The nanoclusters provide large surface area and a lot of active sites for H 2 O 2 reduction. • The best electrodeposition time on material properties for Co–CoMn 2 O 4 /Ni foam electrode is 30 min. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are widely recognized as precursors or sacrificial templates for the synthesis of target catalysts on account of their high porosity and high active surface area. Elemental doping strategy is considered as an effective method for the synthesis of efficient and stable catalysts for electrolytic water. Therefore, in this paper, Ce-doped Ni(OH) 2 nanoparticles and Ni-MOF nanosheets composites were synthesized by electrodeposition using Ni-MOF as precursor. Catalyst Ce–Ni(OH) 2 @Ni-MOF/NF displays excellent OER performance, requiring only 193 mV and 279 mV overpotentials to realize current densities of 10 mA cm−2 and 100 mA cm−2, respectively, while the UOR performance was very remarkable, only a potential of 1.28 V was demanded to reach a current density of 10 mA cm−2. In addition, no obvious change in the overpotential was noticed during the stability test of 16 h, indicating good stability of Ce–Ni(OH) 2 @Ni-MOF/NF. This study provides a meaningful reference for the design of an efficient and stable environmental friendly electrocatalyst. The synthesized Ce–Ni(OH) 2 @Ni-MOF/NF electrode exhibited distinguished electrocatalytic performance toward OER and UOR. [Display omitted] • Ce-doped Ni(OH) 2 @Ni-MOF composite structures exhibit ultrathin nanosheet structures. • Bimetallic synergistic effect promotes electron redistribution at the phase interface. • The performance of catalyst was effectively improved by heteratom doping. • Ce–Ni(OH) 2 @Ni-MOF/NF exhibited superior activity and stability for OER and UOR. [ABSTRACT FROM AUTHOR]

High entropy alloy (HEA) has recently gained attention as one of the promising materials for catalytic field because of its unique structure and multi-constituent synergy catalytic applications due to its diverse element composition and multi-constituent synergy that offered excellent thermal stability, catalytic activity and corrosion resistance. In the work, we introduce the facile preparation of a self-supporting HEA-FeMnCuCo via one-step electrodeposition method, followed by generating HEA multicomponent hydroxyl oxide via a corrosion engineering approach to acquire an efficient and stable alkaline electrolytic catalyst. The prepared catalyst exhibits a remarkable catalytic performance with the overpotentials of 226 mV at current densities of 10 mA cm−2, and a low Tafel slope of 58.2 mV·dec −1. And the high activity is attributed to the formation of transition metal elements (Ni/Fe/Co) with high oxidation states by a corrosion engineering, which increase the active sites and reduced the initial potential of oxygen evolution reaction. Additionally, the HEA catalyst exhibits an excellent long-term OER stability, lasting over 100 h at 50 mA cm−2. • The unique corrosion engineering improves catalytic performance. • The special cauliflower shape increases the active area. • The Ni–Fe–Co with high oxidation state are the true active sites of OER. [ABSTRACT FROM AUTHOR]

The functionalization of basal planes of MoS 2 with S-defects followed by electrodeposition of metallic nanoparticles is a promising strategy to improve their hydrogen evolution reaction (HER) activity. Herein, we demonstrate a uniform electrodeposition of Pd nanoparticles in the presence of a contactless and chemical-free force (i.e., the Lorentz force) induced by an external magnetic field (MF), on exfoliated and desulfurized MoS 2 (MoS 2-x) nanosheets for its improved mass-utilization towards the HER. Interestingly, in the presence of 396 ± 0.01 mT at MoS 2-x electrode surface yields a uniform and narrow distribution of Pd nanoparticles of 4.40 ± 0.03 nm, whereas the absence of MFs results in a non-uniform distribution with a larger size of 11.20 ± 0.39 nm. The catalyst prepared in the presence of 396 ± 0.01 mT exhibits 1.6 times higher HER mass-activity (13.18 A μ g P d − 1 ) at -0.3 V vs RHE than the catalyst prepared without MF (8.18 A μ g P d − 1 ) at the same potential. [Display omitted] • Magnetic fields promote lower-size Pd particles during electrochemical deposition. • Pd@MoS 2-x /4k_396 mT exhibits 1.6 times mass-activity compared to Pd@MoS 2-x /4k_0 mT. • Pd@MoS 2-x /4k_396 mT demonstrates improved durability for hydrogen evolution. [ABSTRACT FROM AUTHOR]

This study investigates the structure, electrochemical behavior and hydrogen evolution reaction (HER) performance of electrodeposited Ru–Co alloy coatings. The alloys were prepared from a 0.75 M Co2+ + 0.025 M Ru3+ solution at various potentials ranging from −0.5 to −1.2 V vs. SCE. Results reveal that the Ru and Co deposition processes are interdependent. The deposition of nobler Ru from the mixed metal solution reaches pure diffusion control already at −0.7 V compared to −1.0 V from a single Ru bath. On the other hand, Co deposition is significantly facilitated in the presence of Ru in the solution. Consequently, as the deposition potential changes from −0.6 to −1.0 V, Ru–Co solid solution coatings characterized by a distinct globular morphology are formed, with their Co content increasing from 22.1/7.4 to 70.2/86.1 wt% for the Cu/Ti 2 AlC MAX phase substrate applied. The alloy catalysts are found to show much better HER activity and stability in alkaline than in acidic solutions. The best Ru–Co@Ti 2 AlC sample, electrodeposited at −0.6 V, requires an overpotential of only −95 mV to deliver a current density of −100 mA cm−2 in 1 M KOH, thus outperforming most Ru–Co-based HER electrocatalysts reported to date. • Ru–Co alloy coatings are potentiostatically deposited on Cu and Ti 2 AlC substrates. • Coatings are composed of a Ru–Co solid solution and possess a globular morphology. • Lowering the electrodeposition potential increases coating thickness and Co content. • The highest HER activity is achieved at ∼10 wt% Co in both acidic and alkaline media. • Thin Ru 93 Co 7 @Ti 2 AlC requires only η = 95 mV to deliver 100 mA cm−2 in 1 M KOH. [Display omitted] [ABSTRACT FROM AUTHOR]

Finding cost-effective electrocatalysts that can match the performance of noble metals like platinum is crucial for renewable hydrogen energy generation. In this study, the electrocatalytic properties of a nickel sulfide compound deposited on a porous copper network that is formed on a nickel foam substrate are investigated. To achieve this goal, the dynamic hydrogen bubble template method was employed. Copper and nickel sulfide electrodeposited in 5 s at 6 A cm−2. The presence of the copper layer resulted in a potential requirement of 98 mV, to achieve current densities of 10 mA cm−2, compared to 120 mV, when the porous copper substrate was not present. The ECSA was found to be significantly increased by the presence of the copper layer, as determined by examining the CV test and calculating the electrochemically active surface area. Ni 3 S 2 @Cu@NF is an excellent choice for electrocatalyst when it comes to HER in alkaline media. [Display omitted] • DHBT were used to electrodeposit coatings of Cu and Ni 3 S 2. • Presence of Cu layer increased electrocatalytic properties of Ni 3 S 2 @Cu@NF. • According to EIS, Ni 3 S 2 @Cu@NF had the best electrocatalytic properties with low R ct. [ABSTRACT FROM AUTHOR]

Chromium electrodeposition from hexavalent Cr (VI) aqueous solutions for Cr thin films and coatings has been vastly used for distinct purposes, due to the attractive appearance and outstanding mechanical, wear and corrosion properties of the resulting coatings. Regardless, its toxicity led to the implementation of European legislation to rescript its use, such as the European Norms Regulation on the Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) and Restriction of Certain Hazardous Substances (RoHS). Thus, a replacement for Cr VI must be found, however, it would be important that the resulting films keep their characteristics. In the literature chromium electrodeposition from trivalent chromium (Cr III) aqueous solutions has been proposed and tested, however, its mechanical and optical properties are not comparable with the ones of Cr VI-based coatings and an alternative method is then required as Cr III alone does not deliver the necessary requirements. In this work, a combination of Cr III electrodeposition (ECD) in conjugation with a physical vapour deposition (PVD) multilayered coating of Cr, N, and C is explored to provide a coating capable of fulfilling the industry requirements. Subjecting the developed samples to a Neutral Salt Spray Test (ISO 9227:2027), shows that both the Cr III and Cr III + PVD coatings have similar results regarding corrosion resistance. Moreover, impedance electrochemical spectroscopy demonstrates the coating porosity as the critical point opening the door to further improvements. Aesthetically, applying the PVD layers allows for replicating the former shiny and black chromed look and expands to more different and appealing colours. Hence, this innovative alternative, based on the use of trivalent chromium by electro-deposition followed by PVD coatings, has proven potential to substitute the hexavalent chromium ECD process, while being a viable and sustainable alternative and expanding its use through different colours. [ABSTRACT FROM AUTHOR]

MXene has excellent capacitive properties as a two-dimensional material, but its cycling stability is poor. β-PbO 2 is one of the common crystalline forms of lead dioxide, and it has excellent electrochemical properties and cyclic stability and has potential as a capacitor electrode material. However, the capacitive performance of β-PbO 2 as a capacitor electrode material is not ideal. Therefore, CF/MXene/β-PbO 2 (CMP) composites were prepared in this study by combining β-PbO 2 with CF/MXene (CM) using a constant current electrodeposition method, and their electrochemical energy storage properties were investigated. The ordered structure of interwoven CF is used to fix MXene, which has metallic properties and large layer spacing, as the matrix material. This utilization enables faster ion transport and electron storage. The electrochemical advantages of β-PbO 2 and CM can be unified by the synergistic effect of the composites, which results in a high specific capacity (399.42 F g−1) of the CMP electrode at 0.2 A g−1. In addition, the CM//CMP asymmetric supercapacitor constructed in 1 M Na 2 SO 4 solution has a wide potential window of 2.0 V and a high specific capacitance of 193.8C g−1, and the capacity remains 54.3% of the initial value after 5000 cycles at a charge/discharge rate of 40 mA g−1. This work provides important research ideas and clues for the application of β-PbO 2 composite electrode materials in supercapacitors. [ABSTRACT FROM AUTHOR]

Developing efficient, economic, and environment-friendly electrocatalysts to meet the industrialized hydrogen evolution reaction (HER) needs is highly desired for dealing with the energy crisis. Under the known premise, how to reasonably control the doping amount of copper greatly influences the structure and is one of the key factors affecting the performance of the catalyst. Herein, a series of Ni–Cu–C electrocatalysts are successfully synthesized through a simple electrodeposition method. The unique dendritic morphology can be obtained by adjusting the different glucose concentrations. DFT simulation reveals that the proper proportion of copper can significantly modulate the H adsorption-free energy Δ G H ∗ It can boost the intrinsic activity of Ni–Cu–C catalysts. NCC-3 delivers an overpotential of 87 mV and 165 mV in alkaline media at the current density of 10 mA cm−2 and 100 mA cm−2, respectively and presents outstanding long-term stability for 50 h. Such excellent HER activity stems from a large ECSA area and better electron-transfer ability. The study presents a feasible way to control metal alloy catalysts' composition in the electrodeposition process. • Ni–Cu–C catalyst with lower overpotential (η 10mA cm −2 = 87 mV) and long-time stability (50 h) was synthesized successfully. • The doping ratio of the Ni–Cu can be controlled by the concentration of glucose in the electrodeposition process. • The Ni–Cu–C catalyst has a unique dendritic morphology with large ECSA area of 210 cm2. • DFT simulation verified that the reasonable doping of copper can moderated H adsorption free energy. [ABSTRACT FROM AUTHOR]

In this work, cobalt oxide decorated on carbon cloth (Co 3 O 4 /CC) is fabricated by the electrodeposition method by optimizing two factors: (i) the electrodeposition time; (ii) the volume ratio between ethylene glycol (EG) and deionized water (DI) in deposition solution. Results indicate that 5 min of electrodeposition is the most effective interval to acquire the sample with the most homogeneous in size and distribution. Furthermore, the addition of EG has a significant effect on the surface morphology of Co 3 O 4 /CC, causing the formation of the mesoporous Co 3 O 4 layers on the substrate's surface. Due to the porous and rough structure of Co 3 O 4 /CC, its specific surface area reaches 111.3 m2g-1 as opposed to pure CC (37.2 m2g-1). Additionally, the coverage of Co 3 O 4 on the cloth helps to enhance the electrochemical surface area up to 10 times and improve strongly the conductivity of the whole system. In the electrochemical water splitting (EWS) application, the Co 3 O 4 /CC sample prepared in precisely 5 min with the existence of EG at 40 %vol. possesses the best electrocatalytic performance with the lowest overpotentials for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with 291 mV and 357 mV at a current density of 10 mA cm−2 for each. This material also exhibits good stability to maintain a stable voltage at 10 mA cm−2 for 30 h. • Co 3 O 4 nanomaterials are synthesized on flexible carbon cloth (CC). • Co 3 O 4 /CC has good ability for both HER and OER. • Vertical CC is the best choice of soft substrate for enhancing conductivity and electron transfer process in HER/OER. • Ratio of EG: DI = 2: 3 exhibits the extraordinary surface for thin well–crystallized mesoporous layers of Co 3 O 4 /CC. • The lowest overpotentials and Tafel slopes for HER (291 mV and 202 mV.dec−1) and OER (357 mV and 283 mV.dec−1). [ABSTRACT FROM AUTHOR]

In the process of electrocatalytic hydrogen evolution, the use of non-polluting and cost-effective dual-functional non-precious metal catalysts is crucial. This study initially prepared CoMnSe 2 on nickel foam via a solvothermal method. By adjusting the doping ratio of Mn, the catalytic performance is further optimized, with the best performance achieved at a Mn doping level of 0.3 mmol (CoMn 0.3 Se 2). To enhance its catalytic kinetics, a metal nickel layer is deposited on CoMn 0.3 Se 2 /NF through electrodeposition, and the influence of electrodeposition time (300, 500, 700 s) on its performance was investigated. The results demonstrated that at an electrodeposition time of 500 s, NiCoMn 0.3 Se 2 /NF-5 exhibited the best electrocatalytic performance. For the hydrogen evolution reaction, it reached −193 mV@100 mA cm−2, while for the urea oxidation reaction, it achieved 1.395 V@100 mA cm−2. A dual-electrode electrolysis cell is established using Ni–CoMn 0.3 Se 2 /NF-5 as both the cathode and anode. In comparison, the cell voltage (1.6 V at 100 mA cm−2) is lower than other materials. The research provides a creative solution for the synthesis of high-performance dual-function catalysts. • Ni was electrodeposited on the surface of CoMn x Se 2 to produce hydrogen. • Ni–CoMn 0.3 Se 2 /NF-5 exhibited excellent catalytic activity towards both HER and UOR. • Compared with pure water splitting, the efficiency of the catalyst is higher with the aid of urea. [ABSTRACT FROM AUTHOR]

Pt-based catalysts are limited in applications greatly due to the scarcity and high cost of the platinum resource. Reducing the load of Pt and improving its utilization are effective strategies to solve the limitations of application for Pt-based catalysts. Herein, a hydrogenated MoO 3 (H x MoO 3 , 0 < x ≤ 2) is employed, which has electrical conductivity as well as reducing properties, to fabricate low-Pt-loading catalysts supported by a carbon cloth (CC) sheet for the hydrogen evolution reactions (HER). Thanks to the single atoms of platinum, the as-prepared Pt/H x MoO 3 @CC catalyst exhibits excellent HER performances and the overpotential is only 53 mV at 10 mA/cm2. The proposed strategy for fabricating Pt-based single-atom catalysts could promote the practical application of the HER of water splitting in electrochemical processes. Catalyst with ultralow Pt loading supported by a carbon cloth can be fabricated by using an electrodeposition method combing with redox reactions. The as-prepared catalyst with ∼0.1 % Pt loading exhibits high HER performance. [Display omitted] • Carbon cloth sheets with uniform H x MoO 3 coatings are prepared by an electrodeposition method. • The reducibility of hydrogenated MoO 3 can achieve Pt loading in single-atom form. • Pt/H x MoO 3 @CC exhibits high HER performance due to the Pt single atoms loading. [ABSTRACT FROM AUTHOR]

A high-performance bifunctional Ni–Fe–Cr electrocatalyst with a coral reef-like porous structure was fabricated by facile one-step electrodeposition at a high cathodic current density of 8 A/cm2 for 30 min in an optimal electrodeposition bath containing 80 g/L CrCl 3 and 1 M NH 4 Cl. The highly porous Ni–Fe–Cr electrocatalyst exhibits extremely low overpotential of 234 mV for oxygen evolution reaction (OER) and 13 mV RHE for hydrogen evolution reaction (HER) in 1 M KOH at a current density of 10 mA/cm2, respectively. The excellent performance of the Ni–Fe–Cr electrocatalyst can be attributed to the modulation of the electronic structure due to the incorporation of Cr enhanced performance capabilities of the porous Ni–Fe–Cr originate from the increased electrochemical active surface area (ECSA), which is 22 times larger than that of thin Ni–Fe–Cr. Moreover, the catalyst exhibits high stability towards the OER and HER in an alkaline solution for 36 h. This work offers a facile synthesis method by which to create a highly porous Ni–Fe–Cr electrocatalyst by electrodeposition and a strategy for increasing the catalytic activity by controlling the pore size. • A high active porous Ni–Fe–Cr electrocatalyst was fabricated by one-step electrodeposition. • The Ni–Fe–Cr composed of 3-D skeleton of the porous structure with 3.8um pore. • The Ni–Fe–Cr exhibits highly active performance for OER and HER. • The overpotential of OER and HER were 234 and 13mV RHE in 1 M KOH at 10 mA/cm2. • The performance was attributed to modulation of electronic structure and enhance ECSA. [ABSTRACT FROM AUTHOR]

Investigation of highly effective and affordable metal-based electrocatalysts is crucial for water splitting that yields pure hydrogen. Herein, using one-step room-temperature electrodeposition, we successfully created a binary metal nickel-iron sulfide bifunctional electrocatalyst having plenty of active sites and a significant specific surface area on nickel foam (NF). Additionally, the synergistic interaction of the two metal components, iron and nickel, facilitates the electron transfer process and increases the materials' electrocatalytic performance. To obtain 10 mA cm−2, the catalyst only requires 75 mV for HER and 210 mV for OER in 1.0 M KOH. The two-electrode electrolyzer only needs a modest driving voltage (1.46 V@10 mA cm−2). The research presented here offers fresh understandings into the water splitting of nickel-iron-based sulfides as well as a reasonable direction for the development of bifunctional electrocatalysts. A simple one-step/one-pot strategy have been developed to synthesize NiFeS/NF which has been demonstrated to be highly active and stable bifunctional HER and OER electrocatalysts, even close to the state-of-art Pt/C and RuO 2 respectively. [Display omitted] • One-step strategy to synthesize phase pure FeNi 2 S 4 doped nickel foam. • NiFeS/NF acts as a highly efficient bifunctional electrocatalyst for water splitting. • Overall activity is comparable to recent bifunctional catalysts reported in the literature. [ABSTRACT FROM AUTHOR]

The influence of Na 2 MoO 4 concentration on the electrochemical deposition of Co–Fe and Co–Fe–Mo alloy coatings from slightly acidic citrate baths and their electrocatalytic performance for alkaline water electrolysis in 1 M NaOH solution have been examined. The chemical composition and the evolution of the crystallographic structure have been analyzed by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), and scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) measurements. Increasing concentration of Mo in the alloy led to gradual amorphization of the crystalline structure. Electrochemical studies revealed that the cathodic Tafel slope reduced to 69 mV/dec for Co–Fe–Mo alloys. Furthermore, a low overpotential value of −121 mV was observed from polarization studies, which confirmed a good catalytic activity for the alkaline water splitting process. • Co–Fe and as Co–Fe–Mo ternary alloys, were fabricated on a copper electrode at different conditions. • Addition of Mo into alloy led to amorphization of the crystalline structure and decrease the overpotential value. • The enhanced activity of Co 57 Fe 24 Mo 19 ternary alloy is related to the synergetic effects between elements. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) electrocatalysts are promised to be extremely important in hydrogen generation of water electrolysis as one of the renewable energy technologies. However, low efficiency and high cost are two crucial barriers that hinder its development and application. Herein, we developed highly efficient NiFe-based self-supported electrocatalysts by a facile two-step electrodeposition method focusing on the porosification of a nickel foam (NF) substrate. The porous nickel layer (PN/NF) formed in the first step by dynamic hydrogen bubble template electrodeposition proved to be effective in facilitating the mass transfer process, and the following second step of nickel-iron deposition (NiFe/PN/NF) continued to increase the intrinsic catalytic activity, with the two synergistically contributing to the excellent OER performance. As an oxygen evolution electrode, it exhibits high catalytic activity in alkaline water electrolysis, which requires only an overpotential of 211 mV to promote the oxidation reaction of water. The overpotentials for the OER at 100, 500 and 750 mA cm−2 are as low as 244, 297 and 326 mV in 1 M KOH, respectively. In 6 M KOH, the overpotentials for driving electrolytic oxygen production at 100, 500, 750 and 1000 mA cm−2 are even lowered spectacularly to 133 mV, 178 mV, 193 mV and 208 mV, respectively. In particular, the catalyst showed a catalytic stability of more than 40 h at a current density of 500 mA cm−2, which presents it as a highly promising candidate for future large-scale industrial applications. • NiFe-oxyhydroxides (NiFeOxHy) self-supported electrocatalysts were studied as electrodes for alkaline electrolyzer. • Facile two-step electrodeposition method was used for the hierarchical three-dimensional structure. • The overpotential for OER at 100 and 500 mA cm−2 are as low as 244 and 297 mV, respectively. • The catalyst showed a catalytic stability more than 40h at a current density of 500 mA cm−2. [ABSTRACT FROM AUTHOR]

A novel thermochemical hydrogen (TCH) sensor was fabricated from a thermoelectric (TE) film and platinum nanoparticle (Pt-NP)-decorated graphene catalyst applied onto the TE film, and its hydrogen (H 2) sensing performance was systemically investigated. Two types of films comprising stoichiometric antimony telluride (Sb 2 Te 3) and a Sb 2 Te 3 /polystyrene (PS) composite were synthesized by cost-effective electrodeposition on a silicon (Si) substrate. The resulting Sb 2 Te 3 /PS composite film played an important role in improving the H 2 sensing signal. Specifically, the sensing signal of the optimized TCH sensor based on the Sb 2 Te 3 /PS composite film was 29.3 times higher than that of the Sb 2 Te 3 -film-based TCH sensor under 2.5 vol% H 2 /air at room temperature (RT). This phenomenon can be explained by the lower thermal conductivity of the Sb 2 Te 3 /PS composite film, increasing the temperature difference relative to that of the Sb 2 Te 3 film. The R-squared correlation coefficient (R2) of the composite-film-based TCH sensor with a range of 400 ppm to 7 vol% H 2 /air was 0.9916. The best response time and recovery time of the composite-film-based sensor were 4 s and 3 s at 3 vol% H 2 /air, respectively. Our results prove that this sensor provides a wide detection range, short response/recovery time, and high sensitivity at RT, which shows its potential for use as a commercial H 2 sensor for infrastructure applications. [Display omitted] • A new method for fabricating hydrogen sensor made up of a Pt/graphene catalyst and a Sb 2 Te 3 /Polystyrene composite film was developed. • Hydrogen response of the sensor was considerably linear at low and high concentrations. • Output voltage signal of the composite film-based sensor is 29.3 times higher than that of the neat Sb 2 Te 3 film under 2.5% H 2 /air. • The sensor can detect a wide range of hydrogen from 400 ppm to 7% with good linearity. • The best response and recovery times of the sensor were 4 s and 3 s, respectively, under 3% H 2 /air. [ABSTRACT FROM AUTHOR]

In order to protect Nb-based alloy from oxidation attack, a Mo layer was first electrodeposited under different current densities and then its siliconized coating was obtained via halide activated pack cementation (HAPC) process. Microstructure, chemical composition, hardness and adhesive strength of the Mo pre-layer on the Nb-based alloy were analyzed and oxidation behavior of the siliconized coating exposed at 1200 °C and 1300 °C was investigated. The results showed that the electrodeposited Mo layer was composed of amorphous Mo phase and MoO 3. The oxygen content in the Mo layer was low as 38.2 at% when the current density during electrodeposition was 400 mA/cm2 with the microhardness as 238 ± 18 HV. The HAPC siliconized coating exhibited a multilayer structure of MoSi 2 /(Mo, Nb) 5 Si 3 /NbSi 2 , which showed an increase in the cohesive/adhesive strength compared to the Mo layer. Mainly Nb 2 O 5 and SiO 2 were formed on the exposed siliconized coating. An accelerated mass gain and a thicker oxidation layer were found as the exposure temperature increased with a thinning of NbSi 2 inner layer. The siliconized coating provided an effective oxidation resistance for the Nb-based alloy and the increased exposure temperature made the protection of the coating deteriorate. [ABSTRACT FROM AUTHOR]

Hydrogen is an ideal energy carrier that can replace non-renewable fossil fuels in the future, and its production using electrochemical water splitting is one of the cleanest and best effective approaches. However, the commercialization of large-scale H 2 production technologies requires earth-abundant electrocatalysts that exhibit Pt-like activity. This study reports, the dual doping of cations (Mo) and anions (S) into metallic NiSe 2 using a green electrodeposition method to upgrade the H evolution reaction (HER) activity and durability of NiSe 2 , at the same time. Sulfur doping into NiSe 2 provides an additional active site, whereas dual doping of Mo/S into NiSe 2 boosts the HER kinetics and durability. Additionally, a NiSe 2 matrix is doped with different concentrations of Mo/S and their HER performance is studied. A 5% Mo/S–NiSe 2 has an optimized H∗ absorption energy, which is favorable for high HER performance. To drive the current densities of −10 and −100 mA cm−2, 5% Mo/S–NiSe 2 electrode requires a small overpotentials of 89 and 222 mV, respectively, and the corresponding Tafel slope is 57 mV dec−1. The enhanced HER activity of Mo/S–NiSe 2 is credited to the electronic structure adjustment, generation of a porous structure, and ample electrochemically active surface area owing to Mo/S dual doping. This strategy is promising for exploring new functional electrocatalysts for clean H 2 production. [Display omitted] • Mo and S are simultaneously doped into metallic NiSe 2 using a green electrodeposition method. • A 5% Mo/S–NiSe 2 has an optimized H∗ absorption energy, which is favorable for high HER performance. • Dual doping of Mo and S into NiSe 2 generates a porous spongy nanoflake-like morphology. • Doping of S or Mo/S modifies the electronic structure of Ni in Mo/S–NiSe 2. [ABSTRACT FROM AUTHOR]

Lower onset potential and uniform distribution of catalytic performance are crucial for catalytic electrodes. This study presents a method for characterizing the spatial distribution of the initial potential on the surface of the oxygen evolution reaction (OER) catalytic electrode using total internal reflection imaging (TIRi). By applying linear sweep voltammetry (LSV) with incremental positive potential to the electrode, the surface of the electrode generates micro-to-nanometer-sized O 2 bubbles during the initial phase of OER, resulting in an increase in light intensity and a decrease in the effective refractive index (RI). By establishing the relationship between light intensity and potential, the spatial distribution of the OER onset potential can be quantified, enabling direct visualization of the electrode's surface and its catalytic activity. Furthermore, we applied the TIRi method to assess the influence of different substrates and electrodeposition conditions on the catalytic activity, repeatability, and durability of NiFe catalytic electrodes. This research contributes to the evaluation of various electrode deposition methods for large-scale catalytic electrodes and the rational manufacturing of efficient OER electrodes in industrial energy devices, promoting the development of the hydrogen energy field. Mappings of OER onset potential, frequency diagrams, and box plots for three different electrodes. [Display omitted] • Distribution map of the OER onset potential was obtained for the first time. • 2k factorial design was used to accelerate the NiFe electrode design. • Activity, repeatability, and durability of NiFe electrodes were studied. [ABSTRACT FROM AUTHOR]

Despite having exciting material characteristics, the potential of multi-component alloys (MCAs) as electrocatalysts has not been fully realized. In this work, efficient binary and ternary MCA electrocatalysts containing inexpensive metals like Co, Mn and Sn have been prepared via the electrodeposition process. When tested for hydrogen evolution reaction (HER) in an alkaline medium, ternary Co–Mn–Sn alloy displayed enhanced activity with the lowest overpotential of 136 mV, a Tafel slope of 111 mV dec−1 and a very low charge transfer resistance, making it superior to the binary alloys (Co–Mn and Co–Sn), or the single metal catalysts (Co, Mn and Sn). The ternary alloy also displayed high electrochemical and structural stability, making it a viable electrocatalyst for the hydrogen economy. [Display omitted] • Multicomponent alloy Co–Mn–Sn, was synthesized by electrodepo-sition. • The HER activity of this alloy was compared with that of commercial catalyst. • Ternary alloy showed better activity than all the other systems investigated here. • Co–Mn–Sn alloy shows the higher electrochemical and structural stability. [ABSTRACT FROM AUTHOR]