Electroless Deposition Method Research Articles

Electroless Deposition of Automatically Shedded Thin Copper Foils.

Electroless deposition (ELD) is a process widely used for the production of thin metal films, but stripping the films from the substrate remains challenging. Here, we report a low-cost ELD method for the large-scale production of freestanding copper (Cu) foils in a short time of 25-55 min. By atomizing a thin (<100 nm) sacrificial layer of chitosan with weak glycosyl bonds and a high degree of deacetylation on the glass substrate, the chitosan is completely decomposed in the process of Cu-deposition, producing automatically shedded Cu foils with varied thicknesses from 746 nm to 8.33 μm and high elastic modulus. When used as battery current collectors, the thin Cu foils with enhanced adhesive fastness and contact areas greatly enhance the capacity and rate capability of graphite anodes. Compared with the commercial Cu current collectors, both the battery capacity and energy density are increased by 429.6 and 484.1%, respectively. The reported approach can be extended for fabricating other metal foils such as nickel with properties appealing for applications.

Fabrication of Ni-ZrO2 Nanocomposite Coating by Electroless Deposition Technique

This work aims preparation of Ni-based nanocomposite coating by electroless deposition method onto stainless steel (316L) substrate, the present work will compare the effects of incorporation of ZrO2 nanoparticles at different percentages (1.25 wt %, 2.25 wt %, and 4.25 wt %) Ni-based electroless deposition coating of the bath nanocomposite on the phase structure, microhardness, and corrosion resistance is studied. Where the structure and chemical composition of nanocomposite coatings were studied by using (X-ray), (SEM) and (EDS). of Ni - ZrO2 nanocomposite coating exhibits much-increased microhardness and remarkably improved corrosion resistance.

Plasmonic Photovoltaics Enabled By Single-Crystal Metal Films and Nanostructures

In contrast to conventional photovoltaic devices which rely on bulk semiconductor material absorption and separation of electron-hole pairs, surface plasmon-based solar energy harvesting employs rectifying metal/dielectric interfaces to capture light and separate charges. Here, we describe the requirements for efficient hot electron extraction in plasmonic photovoltaic devices and demonstrate a new scalable and environmentally friendly electroless deposition method for single crystal epitaxial noble metals films and nanostructures. The method produces ultra-smooth, low loss, single-crystal noble metal films ideal for subtractive patterning of nanostructures through ion beam milling, and high definition, sub-wavelength single crystal nanostructures through lithographic patterning methods. We describe the nucleation and growth of these metal films and nanostructures in the absence and presence of anionic shape-control agents and examine the role of specific anions in determining the resulting film and nanostructure morphologies via scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). These effects have been exploited to yield large area patterned, and shape-controlled nanoarrays of single crystal metal nanostructures for plasmonic and metamaterial applications. These approaches offer new and cost effective routes to achieve crystalline, shape-controlled surface nanostructure to enable efficient hot electron extraction for energy harvesting applications.

Electroactive P-Ani/core-shell/TiO2/TiO2-WO3 employed surface engineering of Ni-P electrodes for alkaline hydrogen evolution reaction

Ni-P coating (NPC) fabricated by electroless deposition has been widely accepted as an effective electrode for alkaline hydrogen evolution reaction. Among the different strategies reported to improve the catalytic activity of Ni-P electrode (NPE) further, incorporation of inorganic metal oxide composite is a proven method. Herein, we propose a modification of TiO2/TiO2-WO3 core-shell structured composite (a novel entity), by the application of conductive polyaniline (P-Ani), as a continuation of our earlier work on its synthesis and characterization. The as-prepared polymer-metal oxide hybrid nanocomposite is then employed to modify the NPE by electroless deposition method. The improved surface characteristics of the modified NPE, after the incorporation of P-Ani/TiO2/TiO2-WO3 composite with reduced charge transfer resistance and low overpotential for alkaline hydrogen evolution (−65mV at −10mA/cm2) corroborates its enhanced catalytic behavior. The increase in the number of catalytically active sites on the NPE after modification through P-Ani composite is attributed to the enhanced characteristics for alkaline hydrogen evolution. Our strategy proposes a sustainable and low-cost electrode material, competent to the existing industrial electrocatalysts, for long term hydrogen evolution in alkaline medium.

Flue gas purification from NO using supported Cu–Mn and Cu–Mn–Nb catalysts synthesized by electroless metal deposition method

In the present work, granular fixed-bed catalysts with active Cu–Mn and Cu–Mn–Nb layers synthesized by electroless metal deposition method were prepared and tested for purification of a flue gas from nitrogen monoxide (NO) by CO. Lightweight expanded clay aggregate with i.d. of 2–4 mm and 8–10 mm was used as a substrate for deposition of the active layer. Elemental composition of the prepared catalytic layers was determined by means of inductively coupled plasma optical emission spectroscopy and energy-dispersive X-ray analysis. Field emission scanning electron microscopy and X-ray photoelectron spectroscopy were applied to investigate morphology of the active layers and the oxidation state of the main components (Mn, Cu and Nb), respectively. Additionally, X-ray diffraction analysis and energy-dispersive X-ray mapping were conducted to provide comprehensive information about the structure and dispersion of active components on the surface of the catalysts prepared. It was demonstrated that electroless metal deposition method allows preparation of a relatively uniform active layer with highly distributed active sites on the substrate surface, while the Cu0.012–Mn0.986Nb0.0012 active layer synthesized by electroless metal deposition can be successfully applied for selective catalytic reduction of NO with the use of CO as a reductant. The effective NO conversion (90–95%) was observed at temperatures of 300–400 °C and higher. X-ray photoelectron spectroscopy revealed that significant amount of Mn3+ and Mn4+ species and predominance of chemisorbed oxygen over the lattice oxygen should be responsible for NO conversion efficiency of the catalyst prepared.

Electroless Deposition of Silver Dendrite Nanostructure onto Glassy Carbon Electrode and Its Electrocatalytic Activity for Ascorbic Acid Oxidation

Well-defined silver dendrite nanostructures with primary and secondary branches on a glassy carbon electrode (GCE) surface are first demonstrated using a simple wet chemical electroless deposition method without any aid of a surfactant. The properties of dendrite structures were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Results of XPS and XRD indicated that most of the silver particles were not oxidized. The obtained silver dendrite GCE (Ag/GCE) showed high electrochemical activity towards catalytic oxidation for ascorbic acid (AA). The oxidation process followed a stepwise mechanism at slower scan rates (υ 0.15 V s-1). The silver nanostructures are stable on the GCE surface and could be employed as an anode for an AA fuel cell.

Carbon-Defect-Driven Electroless Deposition of Pt Atomic Clusters for Highly Efficient Hydrogen Evolution.

Pt atomic clusters (Pt-ACs) display outstanding electrocatalytic performance because of their unique electronic structure with a large number of highly exposed surface atoms. However, the small size and large specific surface area intrinsically associated with ACs pose challenges in the synthesis and stabilization of Pt-ACs without agglomeration. Herein, we report a novel one-step carbon-defect-driven electroless deposition method to produce ultrasmall but well-defined and stable Pt-ACs supported by defective graphene (Pt-AC/DG) structures. A theoretical simulation clearly revealed that the defective regions with a lower work function and hence a higher reducing capacity compared to those of normal hexagonal sites triggered the reduction of Pt ions preferentially at the defect sites. Moreover, the strong binding energy between Pt and carbon defects effectively restricted the migration of spontaneously reduced Pt atoms to immobilize/stabilize the resultant Pt-ACs. Electrochemical analyses demonstrated the high performance of Pt-ACs in catalyzing the hydrogen evolution reaction, showing a greatly enhanced mass activity, a high Pt utilization efficiency, and excellent stability compared with commercial Pt/C catalysts. The integration of proton exchange membrane water electrolysis with Pt-AC/DG as a cathode exhibited an excellent hydrogen generation activity and extraordinary stability (during 200 h of electrolysis) with a greatly reduced Pt usage compared with commercial Pt/C catalysts.

Electroless Plating of NiFeP Alloy on the Surface of Silicon Photoanode for Efficient Photoelectrochemical Water Oxidation.

N-type silicon is a kind of semiconductor with a narrow band gap that has been reported as an outstanding light-harvesting material for photoelectrochemical (PEC) reactions. Decorating a thin catalyst layer on the n-type silicon surface can provide a direct and effective route toward PEC water oxidation. However, most of catalyst immobilization methods for reported n-type silicon photoanodes have been based on energetically demanding, time-consuming, and high-cost processes. Herein, a high-performance NiFeP alloy (NiFeP)-decorated n-type micro-pyramid silicon array (n-Si) photoanode (NiFeP/n-Si) was prepared by a fast and low-cost electroless deposition method for light-driven water oxidation reaction. The saturated photocurrent density of NiFeP/n-Si can reach up to ∼40 mA cm-2, and a photocurrent density of 15.5 mA cm-2 can be achieved at 1.23 VRHE under light illumination (100 mW cm-2, AM1.5 filter), which is one of the most promising silicon-based photoanodes to date. The kinetic studies showed that the NiFeP on the silicon photoanodes could significantly decrease the interfacial charge recombination between the n-type silicon surface and electrolyte.

Highly dispersive Pt–Pd nanoparticles on graphene oxide sheathed carbon fiber microelectrodes for electrochemical detection of H2O2 released from living cells

We report a facile strategy for the synthesis of surfactant-free, small and highly dispersive Pt–Pd nanoparticles on graphene oxide (Pt–Pd NPs/GO) by an electroless deposition method, which is sheathed on carbon fiber microelectrodes (CFMs) as an electrochemical sensing platform for highly sensitive and selective detection of hydrogen peroxide (H2O2) released from the living cells. GO serves as the reducing agent and stabilizer for electroless deposition of Pd NPs on the surface of GO owing to its low work function (4.38 eV) and highly conjugated electronic structure. The obtained Pd NPs/GO have a relatively high work function (4.64 eV), and thereby could be used as stabilizer for synthesis of surfactant-free, small and highly dispersive Pt–Pd NPs/GO by chemical reduction of K2PtCl4. The obtained Pt–Pd NPs have a uniform size of 4.0 ± 0.6 nm on the surface of GO. Moreover, the Pt–Pd NPs/GO sheathed CFMs exhibit an excellent electrocatalytic activity for the reduction of H2O2 with a low detection limit of 0.3 μM and good selectivity. These good properties enable the modified microelectrode to detect the H2O2 released from living cells.

Supported palladium nanoclusters: morphological modification towards enhancement of catalytic performance using surfactant-assisted metal deposition

In the present study, alumina-supported palladium catalysts were prepared by modified electroless deposition (ED) method in presence of surfactants and their performance was significantly improved compared to that prepared in absence of surfactants. Depending on the type and concentration of surfactant, loading and morphology of deposited palladium varied. Both anionic (sodium dodecyl sulphate) and non-ionic (Tween 20) surfactants were observed to be the most effective in dispersing the metals in the precursor solution. Average metal cluster sizes obtained for catalysts prepared by wetness impregnation, modified electroless deposition and surfactant-assisted deposition method were 11.89, 4.6 and 1.18 nm, respectively. The conversion of butane and selectivity to butene was observed to be function of size of deposited Pd cluster. The conversion and selectivity towards butenes increased with the decreasing particle size. The SDS surfactant-assisted prepared catalyst, having the lowest metal cluster size (1.18 nm), showed the highest activity (33% conversion at 600 °C) and over 99% selectivity for butenes.

Nickel boride and cobalt boride coated stainless steel gauze for enhanced electrochemical oxidation of methanol

Ni-Co-B catalyst consisting of different ratios of Ni and Co was successfully synthesized via a simple electroless deposition method on stainless steel (SS) gauze substrate. Among various ratios, the Ni-Co-B of the ratio (0.09 M/0.01 M, designated as Ni-Co-B-MR1) exhibited higher electrochemical response towards methanol oxidation in alkaline medium with a highest current density about 11.3 mA/cm2 at a potential of − 0.65 V. The electrode exhibited improved CO tolerance for methanol oxidation reaction (MOR) in alkaline medium. The surface morphology and composition of the SS gauze coated with Ni-Co-B-MR1 catalyst was analysed using SEM and energy dispersive X-ray analysis. XRD confirms the presence of orthorhombic nickel boride and cobalt boride structure. The XPS analysis confirms the active presence of nickel boride and cobalt boride on SS gauze coated with Ni-Co-B-MR1 catalyst. The BET surface area of SS gauze coated with Ni-Co-B-MR1 catalyst was 1.21 m2 g−1. The single direct methanol fuel cell with SS gauze coated with Ni-Co-B-MR1 electrode produces a current density of about 0.1 mA/cm2 and power density about 10 mW/cm2, respectively.

Graphene oxide reinforced high entropy alloy (CuNiFeCrMo-GO) nanocomposite coating deposited by electroless coating method on mild steel

The present work narrates about the production and characterization of HEA (CuNiFeCrMo)- Graphene oxide (GO) nano composite coating deposited by electroless deposition method, in order to improve the mechanical and surface properties of mild steel substrate. Their microstructure, surface morphology, phase and structure analysis, roughness analysis and micro hardness is observed using scanning electron microscopy - Energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), Atomic force microscopy (AFM) and micro hardness testing respectively. The incorporation of Graphene oxide nanoparticles into CuFeNiCrMo matrix exceedingly improves their mechanical and surface properties. Uniform dispersion of graphene oxide into HEA matrix is confirmed by SEM images. No chloride formation is seen. Micro hardness test reveals that HEA-GO nanocomposite coating improves the hardness of mild steel. This type of nanocomposite coating is suitable for oil and gas pipe lines, automobiles, rocket nozzles, industrial and structural applications etc.

Magnetic properties of Fe-Ni-system films prepared by electroless deposition

We prepared Fe-Ni thick-films (&amp;gt; 1 μm) using an electroless deposition method and evaluated the magnetic properties and the crystal structures. The deposition rate depended on the concentration of dimethylamine-borane (DMAB), which is a reducing agent used in the present study, and we obtained a high deposition rate (&amp;gt; 10 μm/h) for Fe30Ni70 films when the DMAB concentration is higher than 3 g/L. From structural analyses of the films, we found that the films have very fine fcc Fe-Ni crystals in the amorphous magnetic phase. From the investigation of Co additives for the improvement in the surface conditions, we confirmed that a small amount of Co effectively works to obtain the smooth surfaces. As a result, we could obtain the Fe-Ni-system thick-films with low coercivity (50 A/m) and smooth surfaces.

Selective deposition of gold particles onto silicon at the nanoscale controlled by a femtosecond laser through galvanic displacement.

Control of the deposition location and morphology of metals on semiconductors is of considerable importance for the fabrication of metal–semiconductor hybrid structures. For this purpose, selective nanoscale deposition of gold on silicon was successfully achieved by a two-step method in this paper. The first preparation step comprises the fabrication of ripples with a femtosecond laser. The second preparation step is to immerse the samples in a mixed aqueous solution of hydrofluoric acid (HF) and chloroauric acid (HAuCl4). The periodically ablated ripple structures on silicon surfaces fabricated by the femtosecond laser changed the physical and chemical properties of silicon and then controlled the nucleation positions of gold nanoparticles. Gold particles tend to grow in raised positions of the ripples and no substantial growth was observed in the recesses of the ablated ripple structures. Similar phenomena were observed on the modified ripple structures; this led to the formation of periodically distributed gold sub-micron wires. Above all, this paper proposes a new mask-free method of selective metal electroless deposition that can be realized without complicated experimental equipment and tedious experimental operations.

Hierarchical Ni(OH)2/Cu(OH)2 interwoven nanosheets in situ grown on Ni-Cu-P alloy plated cotton fabric for flexible high-performance energy storage.

Flexible energy storage electrodes with high conductivity and capacity are crucial for wearable electronic clothes. Herein, a flexible hierarchical Ni(OH)2/Cu(OH)2 interwoven nanosheets in situ coated on Ni–Cu–P alloy plated cotton fabric textile (NCO/CF), which displays perfect conductive and electrochemical performance, is prepared by electroless deposition and electrochemical oxidation method. While the Ni–Cu–P alloy layer coated on the fabric effectively contributes to excellent mechanical performance and electro-conductivity of the as-prepared NCO/CF electrode, the hierarchical Ni(OH)2/Cu(OH)2 interwoven nanosheets in the oxidation layer effectively lead to a high energy storage performance with a specific areal capacity of 4.7 C cm−2 at a current density of 2 mA cm−2. When the power density of the two-electrode system based on NCO/CF and the carbon cloth (CC) is 2.4 mW cm−2, the energy density is 1.38 mW h cm−2. Furthermore, the flexible solid-state energy storage f-NCO/CF//CC is assembled in a self-powered system and supplies continuous power for electronic devices, demonstrating that NCO/CF is promising to be applied in various energy storage devices to power portable and wearable devices in the future.

Facile one-step synthesis of tunable nanochain-like Fe–Mo–B: A highly efficient and stable catalyst for oxygen evolution reaction

Exploring high-performance and cost-effective non-noble metal electrocatalysts towards oxygen evolution reaction (OER) is critical for large-scale hydrogen production via water splitting. Herein, a series of ternary Fe–Mo–B materials with nanochain-like structure have been successfully fabricated by a green and feasible electroless deposition method. When the molar ratio of Mo/(Mo + Fe) precursor is tuned to 3/100, as-fabricated nanochain-like Fe–Mo–B shows remarkable OER performance with a low overpotential of only 253 mV at current density of 10 mA cm−2 and a small Tafel slope of 63 mV dec−1. In addition, it demonstrates a preeminent long-term electrochemical stability for continuous oxygen generation under alkaline condition. The enhanced OER performance benefits from the synergistic effects between Fe and Mo, bringing about the large electrocatalytic active surface area and fast electronic transfer rate. The work may pave a new path to reasonable design and construct metal-boride-based catalyst with excellent activity for electrocatalytic OER.

Influence of SiC and TiC nanoparticles reinforcement on the microstructure, tribological, and scratch resistance behavior of electroless Ni–P coatings

Two different ceramic carbide nanoparticles (SiC, and TiC) were separately incorporated into the Ni–P matrix via the electroless deposition method. As prepared Ni–P, Ni–P–SiC, and Ni–P–TiC coatings were subjected to heat treatment at 400 °C for 1 h. The surface morphology, microstructural transformation, Vicker’s microhardness, tribological and scratch resistance properties were studied with reference to the different carbide reinforcements as well as heat treatment. Inter-nodular space, craters and kinks are created due to the branching effect of nodules in the surface of the Ni–P–SiC (TiC) composite coatings. After the heat treatment, the matrix phase transformation was not altered due to the incorporation of SiC or TiC into the Ni–P coating; however, a slight increase in residual stress was identified from the XRD analysis. In addition, the content of carbon deposition was found to be higher in the matrix of Ni–P–SiC composite coating than that in the Ni–P–TiC coating. The agglomeration of SiC particles was higher than TiC particles in the coating matrix, which was also supported by the result of Zeta potential measurement. Heat treatment improved wear and coefficient of friction in the Ni–P–SiC and Ni–P–TiC composite coatings. Compared to Ni–P–SiC coating, Ni–P–TiC coating revealed the enhanced tribological and scratch resistance performance after the heat treatment.

Amorphous nickel coating on carbon nanotubes supported Pt nanoparticles as a highly durable and active electrocatalyst for methanol oxidation reaction

Multi-walled carbon nanotubes (CNTs) modified with amorphous nickel coating was reported as a novel support for platinum (Pt) for methanol oxidation reaction (MOR). First, an amorphous nickel coating on pristine CNTs (Ni/CNTs) via a simplified electroless deposition method without sensitization and activation is easily developed. Then, Pt nanoparticles (10 wt%) supported on Ni/CNTs (Pt/Ni/CNTs) were fabricated using a microwave-assisted reduction method. The as-prepared Pt/Ni/CNTs electrocatalyst exhibited higher electrocatalytic activity towards MOR in acidic solution, supported by the fact that its methanol oxidation current density was about 0.38 fold higher than that value of Pt/CNTs. Additionally, the proposed Pt electrocatalyst showed a little better electrocatalytic activity than the Pt/C catalyst containing Pt up to about 20%. Moreover, the Pt/Ni/CNTs also exhibited the best stability during the process of MOR. The improved activity and durability of Pt/Ni/CNTs electrocatalyst can be attributed to a more uniform distribution of Pt nanoparticles as well as the synergistic effect between Pt and amorphous nickel coating. Therefore, the as-prepared Pt/Ni/CNTs electrocatalyst is active and stable, which may be applied to the direct methanol fuel cells with high performance.

Nitrite amperometric sensor for gunshot residue screening

A novel electrochemical sensor comprising a glassy carbon electrode modified with a composite of palladium (Pd) particles and glassy carbon microspheres (GCMs), has been developed to detect gunshot residue via nitrite determination. Pd-GCMs was synthesized through a simple electroless deposition method and characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The electrocatalytic response of nitrite on the Pd-GCMs/GCE is greatly enhanced relative to that on a GCMs/GCE and bare GCE. The applied potential, flow rate and sample volume of flow injection amperometric detection were optimized. The sensor displayed a linear response to nitrite between 0.10 μmol L−1 and 4.0 mmol L−1, with a limit of detection and quantification of 0.030 and 0.11 μmol L−1, respectively. It exhibited very good performance with excellent electrocatalytic activity and high sensitivity (500 ± 5 μA mM−1 cm−2). In addition, the electrochemical sensor presented good repeatability (RSD < 1.5%, n = 20), reproducibility (RSD = 1.4%, n = 6), and operational stability (RSD = 2.8%, n = 268), along with high sample throughput (165 samples h−1). The results of detecting nitrite in gunshot residue with this sensor were in good agreement with those obtained by the Griess method (P>0.05). With its good performance this sensor could be a viable alternative method for detecting nitrite to identify gunshot residue in forensic evaluations via nitrite detection.

Optimal Design of Narrow Line‐Width Front Contact Grid Pattern for Silicon Solar Cells and Low‐Cost Fabrication of Electroless Nickel Plated Imprint Lithography Hard Stamp

Herein, a systematic investigation on the design and development of a cost‐effective nickel hard stamp suitable for fabrication of a new front‐side metallization pattern to reduce the shadow losses in solar cells is demonstrated. Finite element analysis (FEA)–based simulations indicate an optimal finger width of ≈20 μm with interfinger spacing of 1000 μm which can effectively enhance solar cell efficiency by ≈1% due to reduced shadow loss. The optimal grid design is further patterned by means of nanoimprint lithography (NIL) followed by an electroless deposition method. A cost‐effective, electroless deposited nickel hard template is developed for NIL patterning using UV pattern transfer. To avoid the physical damages during the imprinting process and improve the durability of the NIL stamp, silane‐based antiadhesive coating is used which can withstand up to 18 cycles of imprinting process. The nickel hard stamp exhibits improved hardness of 5.63 GPa and roughness of 8 nm and is used to transfer the narrow‐line width patterns during the imprinting process. The proposed industry‐ready technology overcomes the limitations of the existing screen printing process pertaining to the formation of high‐aspect‐ratio narrow line‐width finger grid patterns.