Electroless Chemical Deposition Research Articles

MnO2 decorated silicon nanowires: A novel photocatalyst for improved Rhodamine B removal under visible light exposure

Pollution triggered by organic dyes is a prominent global concern. Thus, it is imperative to devise an effective preventative strategy to tackle this matter. Herein, using the chemical electroless deposition process, a novel SiNWs/MnO2 photocatalyst was successfully manufactured for efficacious photocatalytic purification under visible lighting. Through a series of characterization techniques, the structural, morphological, compositional, and optical features of MnO2-deposited silicon nanowires were thoroughly investigated. The photocatalytic ability of the resultant sample was reckoned by degrading Rhodamine B upon visible exposure. Following 180 min of brightness, the findings found that SiNWs/MnO2 displayed remarkable effectiveness, with a lessening of 93.4 %. The findings demonstrated a significant enhancement in degradation performance linked to the rising surface area and enhanced electron-hole segregation efficiency provided by silicon nanowires. Also, the sample's recyclability was assessed, exhibiting an encouraging sustainability with a slight fall in effectiveness (∼10%) after 6 straight utilizes. Furthermore, scavenging tests have shown that •OH and •O2− were prevalent species accountable for the RhB degradation reaction. Eventually, founded on the results, a plausible mechanism for RhB decomposition was suggested. Altogether, given the straightforward manufacturing method and impressive performance, the study argues that the novel SiNWs/MnO2 might be an intriguing photocatalyst for water contaminant remediation.

Structure and properties of composite nanostructured coatings on steel

Abstract In the recent years, the development of nanotechnology has increased the applications of nanoparticles, and the possibility of incorporating them into innovative composite coatings. In this paper, we aim to improve the corrosion resistance of 42CrMo4 and 65G steels by electroless chemical deposition of Ni, reinforced by adding of nanoparticles of nanodiamants (ND), boron (B) or cubic-BN (CBN). Consequently, by this approach we extend the useful-life of these mechanical parts, making them suitable for aerospace and automotive industry.

The influence of interface products on the mechanical and electrical properties of graphene aluminum composites

Graphene has been identified as an efficient filler to increase the strength and conductivity of aluminum but the reaction between aluminum and graphene at elevated temperature is inevitable. In this research, diverse interfacial products between aluminum and graphene were generated by modulating the sintering temperature, and their influences on the mechanical and electrical characteristics of graphene-aluminum composites were examined. Copper encapsulation on graphene has been utilized to isolate graphene from contacting aluminum directly as well as to doping graphene for conduction purposes. The synthesis of copper-coated graphene-reinforced aluminum composites involved several steps, including electrochemical exfoliation, electroless chemical deposition, mechanical ball milling, and high-pressure sintering. The results demonstrate that the formation of a solid solution between copper nanoparticles and aluminum promotes strong interfacial bonding with graphene, leading to a 22.76 % improvement in the conductivity of the composite compared to the pristine aluminum matrix. Additionally, by minimizing the formation of aluminum carbide, the addition of graphene results in a tensile strength of 404 MPa for the composite material, representing a significant 88.8 % increase over the aluminum matrix.

Understanding the anti-corrosion characteristics of surface modification of h-BN and carbon nanotubes/magnesium composites in simulated seawater.

In order to address the issues of wettability and scattering between matrix and reinforcement and enhance corrosion resistance, the effects of incorporating hexagonal boron nitride (h-BN) into magnesium-carbon nanotubes (Mg-0.5 wt% CNTs) nanocomposites were successfully investigated. An inventive coating with h-BN using a novel electroless chemical deposition technique and double stir casting were used. The composites were produced by varying weight percentages of h-BN (0, 2, 4, and 6). The corrosion testing, microstructural analysis, and physical testing of the samples were carried out. A corrosion resistance of 75.1% was obtained when the 4 weight percent of h-BN content was compared to Mg-0.5% wt% CNTs. Even though the relative density increased noticeably, this was due to the uniform dispersion of h-BN nanoparticles over the entire surface. Researchers have established that adding 4 wt% h-BN to the Mg-0.5 wt% CNT nanocomposite can improve the wettability between Mg and CNTs and enhance the corrosion resistance properties.

Fabrication of a P-Si/ZnO heterojunction based on galvanic cell driven and the complete degradation of RhB via fast charge transfer.

Semiconductor heterojunctions can significantly enhance photocatalytic degradation efficiency by facilitating rapid interfacial charge transfer. This article is based on the galvanic-cell driven principle; porous silicon (P-Si) was prepared by the carbon-catalytic etching method, and ZnO was loaded on its surface via electroless chemical deposition technology to form a P-Si/ZnO heterojunction, which was applied to the degradation of Rhodamine B (RhB). At a deposition temperature of 90 °C, a flawless 1D hexagonal prism structure of ZnO was formed, allowing the P-Si/ZnO heterojunction to completely degrade RhB within 2 hours with a degradation rate of 100%. Compared with a single P-Si material, the degradation performance is improved by 1.7 times. The formation of the built-in electric field and the rapid charge transfer at the heterojunction interface realized the complete degradation of RhB organic pollutants. After 20 cycles of use, the photocatalytic degradation rate remains above 70%, demonstrating excellent stability and recyclability.

Mechanical Properties and Corrosion–Electrochemical Behavior of Multilayer Coatings of the Ni–P and W–C System Obtained by the Electroless Plating Method and Chemical Vapor Deposition. Part 1. Structure and Mechanical Properties of Coatings

Mechanical Properties and Corrosion–Electrochemical Behavior of Multilayer Coatings of the Ni–P and W–C System Obtained by the Electroless Plating Method and Chemical Vapor Deposition. Part 1. Structure and Mechanical Properties of Coatings

Wet Chemical Synthesis and Characterization of Au Coatings on Meso- and Macroporous Si for Molecular Analysis by SERS Spectroscopy

Porous silicon (PS) is a promising material for nanostructure fabrication providing a precise control over its size, shape, and spatial distribution. This makes it an excellent candidate for constructing highly sensitive, reproducible, and low-cost platforms for surface enhanced Raman scattering (SERS) spectroscopy. In this work, we connect the PS structural parameters with the morphology of the gold nanostructures fabricated on its surface, placing the emphasis on the SERS response. Two different types of PS are considered here, namely meso- and macro-PS. The former is prepared by Si electrochemical etching, applying three different current densities: 100 mA cm−2, 60 mA cm−2, and 30 mA cm−2, while the technological parameters for the latter are selected to mimic metal nanovoids’ (Me NVs) configuration. The gold-coated PS surfaces are produced via an electroless chemical deposition method for different time periods. By performing comprehensive structural, morphological, and optical characterization, we show the importance of the size and density of the PS pore openings, which govern the Au growth kinetics. The results presented in this work assure a simple yet flexible approach for the fabrication of large-area plasmonic gold nanostructures, which are not only suitable for advanced SERS spectroscopy studies but can also serve for a wider range of plasmonic applications.

Studying the Microstructure, Physical and Mechanical Properties of Al Matrix Reinforced with Bi-Modal Particles Coated with Either Ni or Cu

Powder metallurgy was used to fabricate Al/(SiC-Y2O3)/Ag/Cu or Ni nanocomposite. The ratio of SiC to Y2O3 was 50:50. SiC-Y2O3 particles were coated with 10 wt% nano-Ag, followed by coating with another layer of 10% nano-Ni or nano-Cu by an electroless chemical deposition technique. All samples were compacted by a uniaxial press under 480 MPa and then sintered in a vacuum furnace at 600 °C for 1 h holding time. Coated samples with nano-Cu have the highest densification values. The microstructure of nano-Cu-coated composites is more homogenous than nano-Ni ones. X-ray diffraction analysis (XRD) indicated the presence of Al peaks as a major phase, and Al3NiSi and AlCu intermetallics are detected. Also, traces of SiC and Y2O3 peaks are recorded. Hardness results showed that (SiC-Y2O3)/ nano-Ag/nano-Cu samples have higher hardness values than nano-Ni samples. Also, both the electrical and thermal conductivities are higher for nano-Cu-coated samples than for nano-Ni coated ones.

Increasing the structural and compositional diversity of ion-track templated 1D nanostructures through multistep etching, plastic deformation, and deposition

Ion-track etching represents a highly versatile way of introducing artificial pores with diameters down into the nm-regime into polymers, which offers considerable synthetic flexibility in template-assisted nanofabrication schemes. While the mechanistic foundations of ion-track technology are well understood, its potential for creating structurally and compositionally complex nano-architectures is far from being fully tapped. In this study, we showcase different strategies to expand the synthetic repertoire of ion-track membrane templating by creating several new 1D nanostructures, namely metal nanotubes of elliptical cross-section, funnel-shaped nanotubes optionally overcoated with titania or nickel nanospike layers, and concentrical as well as stacked metal nanotube-nanowire heterostructures. These nano-architectures are obtained solely by applying different wet-chemical deposition methods (electroless plating, electrodeposition, and chemical bath deposition) to ion-track etched polycarbonate templates, whose pore geometry is modified through plastic deformation, consecutive etching steps under differing conditions, and etching steps intermitted by spatially confined deposition, providing new motifs for nanoscale replication.

Electrochemical Behavior of Cu-MWCNT Nanocomposites Manufactured by Powder Technology

This paper presents an experimental investigation of the fabrication of Cu–multi-walled carbon nanotube (MWCNT) nanocomposites prepared via the electroless chemical deposition technique followed by the powder metallurgy (PM) method. To enhance the dispersion and wettability of MWCNTs with a Cu matrix, MWCNTs were given an electroless coating of Ag nanoparticles. MWCNTs with 0.4, 0.8, and 1.2 wt.% were first coated with 5 wt.% Ag nanoparticles, then mechanically milled with Cu nanoparticles using a 10:1 ball-to-powder ratio for 60 min at 300 rpm. The mixed samples (35 g) were subjected to a compression pressure of 700 MPa and sintered at 950 °C in a hydrogen-inert gas furnace. Mapping and microstructure analyses were conducted to analyze the constituents’ homogeneity. In addition, the electrochemical properties and corrosion resistance of specimens were investigated. The results revealed that the relative density decreased by raising the MWCNTs’ content. Electrical resistivity increased gradually with the addition of MWCNTs coated by Ag nanoparticles, and the thermal conductivity decreased. It was also revealed that the smallest corrosion rate could be obtained for the sample with 1.2 wt.% MWCNTs, which is the appropriate rate for the electrochemical deposition.

Size-Controlled Synthesis of Pd Nanocatalysts on Defect-Engineered CeO2 for CO2 Hydrogenation.

The size effects of metal catalysts have been widely investigated to optimize their catalytic activity and selectivity. However, the size-controllable synthesis of uniform supported metal nanoparticles without surfactants and/or additives remains a great challenge. Herein, we developed a green, surfactant-free, and universal strategy to tailor the sizes of uniform Pd nanoparticles on metal oxides by an electroless chemical deposition method via defect engineering of supports. The nucleation and growth mechanism suggest a strong electrostatic interaction between the Pd precursor and low-defective CeO2 and a weak reducing capacity for low-defective CeO2, resulting in small Pd nanoparticles. Conversely, large Pd nanoparticles were formed on a highly defective CeO2 surface. Combined with various ex situ and in situ characterizations, a higher intrinsic activity of Pd for the CO2-to-CO hydrogenation was found on large Pd nanoparticles with higher electron density owing to their stronger H2 dissociation ability and H-spillover effects, as well as the larger number of oxygen vacancies generated in situ for CO2 activation under hydrogenation conditions.

Interferometric optical fiber sensor for optoacoustic endomicroscopy

Optical fiber sensors can offer robust and miniaturized detection of wideband ultrasound, yielding high sensitivity and immunity to electromagnetic interference. However, the lack of cost-effective manufacturing methods prevents the disseminated use of these sensors in biomedical applications. In this study, we developed and optimized a simple method to create optical cavities with high-quality mirrors for acoustic sensing based on micro-manipulation of UV-curable optical adhesives and electroless chemical silver deposition. This approach enables the manufacturing of ultrasound sensors based on Fabry-Pérot interferometers on optical fiber tips with minimal production costs. Characterization and high-resolution optoacoustic imaging experiments show that the manufacturing process yielded a fiber sensor with a small NEP ( ) over a broad detection bandwidth (25 MHz), generally outperforming conventional piezoelectric based transducers. We discuss how the new manufacturing process leads to a high-performance acoustic detector that, due to low cost, can be used as a disposable sensor.

Catalytic superlubricity: engineering superlubricity caused by the catalytic effect of gold on hydrogenated amorphous carbon structure

<p indent="0mm">Material and energy losses caused by friction and wear hinder the development of mechanical systems. An effective way to solve the problem is to reduce friction coefficient and wear. Here, we proposed <italic>in-situ</italic> formation of graphene nanoribbons <italic>via</italic> gold-catalyzed reconstruction of amorphous hydrogenated carbon matrix to achieve engineering superlubricity. And we called this method “catalytic superlubricity”. In detail, amorphous hydrogenated carbon (a-C:H) films were grown by plasma chemical vapor deposition (PECVD), and gold (Au) films on steel balls were obtained by electroless chemical deposition. Comparing study on the tribology properties of the couple pairs of a-C:H/Au and a-C:H/GCr15 was carried out <italic>via </italic>home-made Tribometer 3. The results show that, compared with the couple pairs of a-C:H/GCr15 (<italic>μ</italic>~0.032 and wear depth of <sc>128 nm</sc> ), the couple pairs of a-C:H/Au show a friction coefficient of 0.008 and wear depth of <sc>40 nm,</sc> respectively. The reason of superlubricity of the couple pairs of a-C:H/Au is that, based on the catalysis of gold, the graphene nanoribbons formed <italic>in-situ</italic> during friction. The ordered structure is conducive to the occurrence of incommensurate contact, and effectively reduces the interfacial shear force and thus lowers the friction coefficient.

Effect of nano Al2O3 coated Ag addition on the corrosion resistance and electrochemical behavior of Cu-Al2O3 nanocomposites

Cu-Al2O3 coated Ag nanocomposite is prepared by electroless chemical deposition, followed by PM technique. Nano Al2O3 by 3, 6, 9, and 12 wt.% is firstly coated with 5 wt.% nano Ag then the above four mentioned percent are mechanically milled with nano copper for 1 h by 350 rpm. Followed by compacted under 700 MPa, then sintered at 950 °C in H2 gas inert. The microstructure and mapping were estimated to evaluate the homogeneity of constituent. The amount of relative density decreases with increasing the content of Al2O3 nanoparticles. In addition, electrical resistivity is increase gradually by the addition of Al2O3 coated Ag and thermal conductivity decrease by increasing the Al2O3 coated Ag nanocomposite content. The electrochemical behavior and corrosion resistance of the prepared samples are studied. The resultant indicates that 9 wt.% Al2O3 sample has the lowest corrosion rate. In addition, it is the most suitable for electrochemical deposition.

Effects of silver nanoparticles layer thickness towards properties of black silicon fabricated by metal-assisted chemical etching for photovoltaics

This paper investigates effects of silver nanoparticles (Ag NPs) layer thickness towards properties of black silicon (b-Si) fabricated by two-step metal-assisted chemical etching for potential application in photovoltaic (PV) devices. Ag NPs with different layer thicknesses (1.3–5.1 µm) are deposited on monocrystalline silicon (mono c-Si) wafers by electroless chemical deposition in AgNO3/HF aqueous solution for 10–40 s. This is followed by etching in HF:H2O2:DI H2O aqueous solution for 20 s. Surface morphological investigation confirms presence of b-Si nanowires with height of 250–577 nm and diameter of 100–200 nm. The b-Si nanowires suppress broadband reflectance from the wafers over 300–1100 nm wavelength region, due to refractive index grading effect. Sample with Ag NPs layer thickness of 5.1 µm exhibits b-Si nanowires with average height of 577 nm and average diameter of 200 nm after etching. This sample demonstrates the lowest weighted average reflectance of 5.5% compared to other samples. This sample exhibits absorption of 96.5% at wavelength of 600 nm. The enhanced broadband light absorption leads to maximum potential short-circuit current density (Jsc(max)) of 39.7 mA/cm2, or 51% relative enhancement compared to planar reference sample.

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.

Si/Cu3Si/Cu composite material synthesized by low cost and high efficiency method as anode materials for lithium-ion batteries

In this work, submicron silicon(Si) particles obtained from ball-milling the broken crystalline Si wafers was modified with nanosized copper(Cu) particles by electroless chemical deposition. As-deposited Si/Cu particles was further annealed by rapid thermal process to attain beneficial SiCu alloy at contact interface. The bare Si, as deposited Si/Cu and Si/Cu3Si/Cu composite particles were made into Li-half cells to measure electrochemical performance. The discharge specific capacity of Si/Cu3Si/Cu composite is up to 997 mAhg−1 at current density of 8.4 Ag−1 (2.0 C), which is over 100% higher than Si. Furthermore, the discharge specific capacity of Si/Cu3Si/Cu composite exhibits 1126 mAhg−1 after 100 cycles under current density of 0.5 C, exceeding that of Si by 216%.Owing to the better conductivity from copper, and interface alloy transitive structure enhancing the combining strength, Si/Cu3Si/Cu composite particles exhibit the excellent electrochemical performance.

Uniform small metal nanoparticles anchored on CeO2 nanorods driven by electroless chemical deposition

We report a facile electroless chemical deposition (ECD) method to deposit uniform Pd nanoparticles ((2.5 ± 0.6) nm) on CeO2 nanorods (PdNPs/CeO2-ECD) through the interface redox reaction between the reduced CeO2 and Na2PdCl4. PdNPs/CeO2-ECD exhibits a stronger electronic metal–support interaction (EMSI) evidenced by higher reducibility and stronger anti-sintering capability at high temperatures, compared to that prepared by the conventional impregnation method. Such an EMSI effect of PdNPs/CeO2-ECD significantly improves its catalytic activity in CO oxidation. Besides, the chlorine residue-free catalysts through ECD process avoid the deleterious effect of chlorine on CO oxidation. This ECD process can further be extended to deposit various uniform nanoscaled noble metals (Au, Ag, Pt, Ru, Rh, etc.) on CeO2, which may deliver their potentials in advanced catalysis.

Simple Electroless Synthesis of Cobalt Nanoparticle Chains, Oriented by Externally Applied Magnetic Fields

Abstract The electroless (chemical) deposition of cobalt on palladium-sensitized oxidized silicon wafers produces nanowires and chains made up by nanoparticles. We demonstrate that the application of moderate magnetic fields, provided by permanent magnets, during the growth produces highly oriented cobalt nanowires and nanoparticle chains. By adjusting the magnetic field direction in plane, parallel and crossed cobalt chain patterns are readily accessible. Perpendicular orientation of the field results in rod-like, standing-up chains of nanoparticles. We explain the observed structures with magnetostatic arguments.

Morphological Control in Solution-Deposited Silver Nanoplatelet Films

Recently we introduced a new electroless plating (EP) strategy based on a plating bath containing Fe(III) tartrate, a metal complex surfactant, which is capable of producing a variety of previously undescribed silver nanoplatelet architectures (Fig. 1a) [1, 2]. Likewise to conventional colloidal syntheses, in-plane growth is promoted by stacking faults, while out-of-plane growth on (111) oriented surfaces is efficiently suppressed by effective passivation with adsorbed layer of Fe(III) tartrate. In this research we focused on evaluation of parameters which define the formation of nanoplatelet films. We found that morphology of Ag nanoplatelets deposited on variety of materials such as Pt, Ag, Au, highly ordered pyrolytic graphite (HOPG), mica, thermally oxidized silicon, and indium tin oxide is very robust. The general nanoplatelets structure was found in all cases, although the substrate type had some effect on the deposit morphology. The Ag nanoplatelets deposited on Pt grew to much larger size than during EP on other materials, most probably due to contribution of the Pt substrate to tartrate oxidation. EP on Ag substrate resulted in the suppression of the hierarchical layer of small nanostructures, with only large nanoplatelets emerging from the substrate (Fig. 1b). This could be explained by the strong passivating effect of the Fe(III) tartrate complex on Ag surfaces, which could be seen in the absence of any notable deposits apart from the large, spread-out nanoplatelets. Deposition of metals is generally performed either in conditions of electroless plating or under electrochemical control. Here we studied the influence of electrochemical control on morphology of Ag deposited on Ag electrode from electroless plating bath. We revealed that morphology of Ag deposit could be tuned by change in the applied overpotential. At moderate overpotential formation of nanoplatelets was preserved (Fig. 1c), indicating effective passivation of (111)- oriented facets by adsorbed Fe(III) tartrate layer (Fig. 1d) while growth proceeded in <211> directions of Ag lattice similarly to EP [2]. Deposition under potential control increased density of of Ag nanoplatelets and their lateral size decreased when compare to EP (Fig. 1b). Increase of the overpotential induced secondary nucleation on (111) surfaces that proceeded simultaneously with 2D growth of nanoplatelets, resulting in radical changes in morphology of Ag nanostructures (Fig. 1e). Interesting variation of the Ag nanostructure morphology was also obtained when EP combined with potential control was performed using plating solution with decreased concentration of tartrate. These conditions resulted in formation of large well-defined Ag crystals instead of nanoplatelets (Fig. 1f). Remnants of platelet motive were still seen, however, as blade-like protrusions (see arrow in Fig. 1f). We assume that introduction of electrochemical control during electroless (chemical) deposition opens new possibilities of tuning morphology of nanostructured films. F.M. acknowledges funding by a Research Fellowship of the German Research Foundation (MU 4125/1-1). Prof. Israel Rubinstein passed away on October 21, 2017. Figure 1