Search Results (506)

Due to their unique properties resulting from the combination of metals with different properties, bimetallic sheets are desirable in the energy, petrochemical, and shipbuilding industries. In this article, explosively welded EN AW-1050/Cu-ETP (Al/Cu) plates were used as the test material. One of the greatest advantages of Al/Cu bimetallic plates is their high deformability, which allows for easy plastic forming. The aim of this study was to determine the effect of severe plastic deformation on the microstructure and microhardness of explosively welded EN AW-1050/Cu-ETP plates. Bimetallic samples were processed using the Twist Channel Angular Pressing (TCAP) process. This process consisted of varying the number of passes and the sample orientation relative to the helical exit channel of the TCAP die. For comparative purposes, a microstructural analysis and the microhardness testing of the as-welded samples were also carried out. Microstructural analysis of TCAP-processed samples showed that the sample deformed along route Bc exhibited the most deformed weld interface profile. No cracking or delamination was observed in the Al/Cu interfacial transition layer of TCAP-processed samples. The number of passes and orientation of the bimetallic material relative to the die exit channel affected the final microhardness in the individual layers of explosively welded EN AW-1050/Cu-ETP bimetallic plate. Full article

Zeolite imidazolate frameworks (ZIFs)-derived carbon materials have garnered widespread attention as peroxymonosulfate (PMS) activators in removing antibiotics because of their excellent catalytic performance. However, most carbon materials derived from ZIFs exhibit limited efficacy in treating high-concentration (>10 ppm) antibiotic wastewater, and their synthesis methods are environmentally unfriendly. Herein, we develop a simple and environmentally friendly preparation method to synthesize a new type of nitrogen-doped carbon-supported carbon nanotubes coated with cobalt nanoparticle (Co-CNTs@NC) composites via high-temperature calcination of cobalt–zinc bimetallic ZIFs. The material characterization results confirm the successful preparation of Co-CNTs@NC composites featuring a high specific surface area (512.13 m²/g) and a Co content of 5.38 wt%. Across an initial pH range of 3.24–9.00, the Co-CNTs@NC/PMS catalytic system achieved over 84.17% degradation of 20 mg/L tetracycline hydrochloride within 90 min, demonstrating its favorable pH tolerance. The singlet oxygen-dominated degradation mechanism was confirmed by quenching experiments and electron paramagnetic resonance characterization. This work can provide technical guidance and reference significance for the preparation of metal–carbon materials derived from ZIFs with excellent efficiency of removal of high-concentration antibiotics. Full article

Photo-Fenton advanced oxidation processes are promising and sustainable approaches for water treatment, particularly under visible-light irradiation. In this study, Cu-Fe bimetallic catalysts supported on silica and γ-alumina were developed for visible-light-driven photo-Fenton reactions, with emphasis on the influence of metal ratios and support-metal interactions on charge–carrier dynamics and hydroxyl radical formation. Comprehensive characterization (XRD, TEM, UV-Vis DRS, PL, TCSPC, and EPR) revealed stronger metal–support interactions and higher metal dispersion on γ-alumina, while silica-supported catalysts showed CuO aggregation at higher Cu loadings. Catalytic performance was evaluated using coumarin oxidation as both a model reaction and a quantitative probe for ^•OH radical generation. Alumina-supported catalysts exhibited superior activity, and ^•OH production increased with increasing Cu content on both supports. Importantly, iron was found to play a dual role: low Fe loading enhances photo-Fenton activity, whereas higher Fe content promotes charge–carrier recombination, leading to reduced activity under visible-light irradiation. These results highlight how the interplay between Fe/Cu ratio and support material governs charge dynamics and provides clear guidelines for the rational design of efficient heterogeneous photo-Fenton catalysts. Full article

Study presents a comparative analytical investigation into the green synthesis of monometallic and bimetallic nanoparticles using Punica granatum (pomegranate) extract, aimed at developing high-performance electrochemical sensors for the detection of ciprofloxacin (CIP) as a representative pharmaceutical pollutant. Three nanoparticle systems were successfully synthesized: monometallic Au@NPs and TiO₂@NPs, as well as the bimetallic AuTiO₂@NPs. Their structural and physicochemical characteristics were comprehensively analyzed using UV–Vis spectroscopy, FTIR, SEM, TEM, and XRD techniques. The obtained nanoparticles exhibited predominantly spherical morphologies with average particle sizes of approximately 40 ± 5 nm for Au@NPs, 50 ± 7 nm for TiO₂@NPs, and 60 ± 6 nm for AuTiO₂@NPs. These nanomaterials were subsequently employed to modify electrode surfaces for electrochemical sensing applications. Their analytical performance was evaluated using cyclic voltammetry (CV) and square-wave voltammetry (SWV). The sensors displayed excellent sensitivity, with limits of detection of 0.8 ppb for TiO₂@NPs, 0.8 ppb for Au@NPs, and 0.2 ppb for the AuTiO₂@NP-based sensor. The bimetallic platform demonstrated superior electrochemical behavior, enhanced signal intensity, and strong selectivity, achieving recovery rates of 98% in tap water and 103% in wastewater. Overall, the results confirm the effectiveness of green-synthesized bimetallic nanoparticles as efficient, low-cost materials for environmental monitoring of emerging pharmaceutical contaminants. Full article

Copper-based electrocatalytic materials with high surface area are essential for various processes, such as water splitting and the electroreduction of carbon dioxide and nitrates. Three-dimensional nanostructured electrodes offer distinct advantages in these applications due to their expansive surface area, which enhances charge transfer and mass transport. For bimetallic systems, however, the phase state, whether a solid solution or a mechanical mixture of metals, is critically important for catalytic performance. This study explores the formation of Cu-Ni solid solutions via electrodeposition using the dynamic hydrogen bubble template method. Two types of electrolyte were employed: sulfate-based and citrate-based. Through characterization by X-ray diffraction, scanning electron microscopy, elemental mapping, and X-ray fluorescence spectroscopy, we demonstrate that metallic foams deposited from sulfate solutions are heterogeneous, with poor control over nickel content. In contrast, the use of citrate-based solutions allows the nickel content in the deposits to be effectively controlled by varying the solution composition, thereby enabling the formation of a solid solution. Full article

The surface modification of medical implant materials stands as a favorable strategy to enhance their biological properties including their antibacterial effect and biocompatibility. Recently, both in vitro and in vivo studies have shown that film heterostructures based on a combination of noble metal sublayers and an active component, such as silver and gold nanoparticles, offer unique advantages. The present work develops this promising direction and focuses on a series of combinations of noble metal coatings functionalized with bimetallic nanoclusters obtained by vapor-phase deposition methods onto the surfaces of Ti-based implants. This investigation investigates the influence of sequential deposition (AgAu or AuAg) and noble metal component (Ir or Au) on the coating morphology and the active component chemical form and release. Thus, scanning electron microscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission spectroscopy have been applied to characterize the samples before and after in vivo biological studies (rat models, 1 and 3 months). Histological and blood analyses confirmed the high biocompatibility of all the heterostructures. The samples also showed a pronounced in vitro biocidal effect against Gram-positive (S. epidermalis) and Gram-negative (P. aeruginosa) bacteria that correlates with a dynamic of silver release. The AuAg/M heterostructures demonstrated superior biological characteristics compared to their AgAu/M counterparts, suggesting enhanced both long-term integration and antibacterial action. Full article

At present, various carbon materials are available as supports for metal-containing catalytic species. Carbon-based materials find application in many industrial heterogeneous catalytic processes, such as selective hydrogenation, oxidation, cross-coupling, etc. The simplicity of preparation, low cost, high stability, and the possibility of tuning surface composition and porosity cause the widespread use of metal catalysts supported on carbon materials. The surface chemistry of carbon supports plays a crucial role in catalysis, since it allows for control over the sizes of metal particles and their electronic properties. Moreover, metal-free functionalized carbonaceous materials themselves can act as catalysts. In this review, we discuss the recent progress in the field of the application of carbon supports in catalysis by metals, with a focus on the role of carbon surface functionalities and metal-support interactions in catalytic processes used in fine organic synthesis. Among carbon materials, functionalized/doped (O, N, S, P, B) activated carbons, graphenes, carbon nanotubes, graphitic carbon nitride, and carbonizates of polymers are considered supports for mono- and bimetallic nanoparticles. Full article

Liquid organic hydrogen carriers (LOHCs) are promising materials for safe, reversible, and high-density hydrogen storage. Atomically dispersed bimetallic Pt–Sn nanocluster catalysts supported on TiO₂ (Pt–Sn/TiO₂) were developed to enhance the hydrogenation step in the toluene-methylcyclohexane cycle, a model LOHC system. Compared with monometallic Pt/TiO₂ and Sn/TiO₂, Pt–Sn/TiO₂ exhibited superior hydrogenation performance. Mechanistic studies, including X-ray photoelectron spectroscopy, kinetic analysis, and H₂-D₂ exchange experiments, revealed that Sn incorporation modulates the electronic structure of Pt, enhancing H₂ activation and spillover. These findings provide insights into the rational design of atomically dispersed bimetallic nanocluster catalysts for efficient and durable hydrogen storage in LOHC-based systems. Full article

In this work, bimetallic specimens of the copper C11000-Inconel 625 system were fabricated using multi-wire electron beam additive technology. Three different sequences of component deposition were employed to produce the bimetallic specimens for investigation: Type A—nickel and pure copper were deposited side by side in parallel; Type B—layers of nickel-based superalloy were printed first, followed by the deposition of copper on top; Type C—copper layers were printed first, with nickel-based superalloy subsequently deposited on top. The influence of additive manufacturing conditions and sequence on the microstructure, static and fatigue strength, and impact toughness of the test pieces was studied. The results indicate the formation of a complex anisotropic structure in bimetals of various types during printing, driven by directional heat dissipation toward the substrate. The microstructure comprising large primary grains or dendrites elongated along the heat flow direction leads to significant differences in material properties along the printing (scanning) direction, the build (growth) direction, and at intermediate angles. Studies of the copper C11000-Inconel 625 bimetallic samples have shown that the interface between components does not exhibit inherent weakness compared to the base materials: pure copper or nickel superalloy. Tensile testing consistently reveals that fracture occurs by the adhesive mechanism in the weaker constituent, rather than at the interface. Full article

In this work, a novel mixed-component bimetallic metal–organic framework (MOF) composite material was synthesized via a solvothermal approach, and its structural and textural properties were systematically characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), N₂ adsorption/desorption analysis, and transmission electron microscopy (TEM). Furthermore, the single-component adsorption isotherms of CO₂ and N₂ were experimentally measured and fitted to the Langmuir–Freundlich model. The CO₂/N₂ selectivity of the composite was evaluated based on the ideal adsorption solution theory (IAST). The results demonstrated that the addition of Zn²⁺ significantly enhanced the specific surface area and improved the CO₂ adsorption capacity (3.97 mmol/g at 35 °C and 1 bar), with an increase of 31.5% in comparison with the Cu-BTC/MCFs (3.02 mmol/g). Meanwhile, the Zn-Cu-BTC/MCFs had good recyclability and CO₂/N₂ selectivity up to 12.5 determined via IAST (CO₂:N₂ = 85:15). Full article

In the aerospace sector, integrating advanced materials with high mechanical capabilities represents the forefront of material science, especially in the field of rocketry. Bimetallic structures are increasingly used in aerospace applications due to their combination of high strength-to-weight ratio, thermal conductivity, and corrosion resistance. Among these, Inconel-copper (In718-Cu) systems are particularly promising, although large differences in thermophysical and mechanical properties between the two materials can induce residual stresses, cracks, and other interfacial defects, requiring careful process control. This study evaluates the fabrication of In718-Cu structures through Direct Energy Deposition (DED), in which In718 was deposited onto a copper substrate using an innovative deposition strategy. Interface quality and microstructure were characterized by SEM/EDS and X-ray diffraction, whereas the mechanical properties were evaluated by nanoindentation, indentation creep, and tensile testing. The results showed that crack-free samples can be achieved, with strong diffusion bonding at the interface and efficient precipitation strengthening on the copper side already in the as-built condition. A uniform distribution of precipitates and consistent penetration depth were also observed, confirming the effectiveness of the deposition strategy for producing reliable In718-Cu components. Full article

Since the discovery of carbon nanotubes (CNTs), extensive and comprehensive research has been conducted in many areas of materials science. Due to their structural and chemical properties, they can be an important part of electronic devices and structural materials that surround us. In this work, we focused on the preparation and basic analysis of vertically aligned CNTs. An aluminum oxide carrier layer and bimetallic iron–cobalt catalyst layers of different compositions were fabricated on the surface of a silicon substrate using a pulsed laser deposition method. Then, vertically aligned CNTs were grown using a catalytic chemical vapor deposition method based on the thermal decomposition of ethylene. During the experiments, the effect of water vapor and hydrogen gas was investigated on the structure of as-prepared carbon nanotubes. CNT forest samples were characterized by scanning electron microscopy and Raman spectroscopy. One of the most important findings of this research is that the presence of hydrogen gas in the CCVD system is essential, but high-quality vertically aligned CNTs can be produced on silicon substrates even without water vapor. Full article

Incorporating Cu into gold-based catalysts effectively reduced nanoparticle sintering and free carbonate accumulation, promoting long-term preservation of catalytic surface area over time. This study explores the catalytic activity of monometallic Au and bimetallic AuCu catalysts with varying Au:Cu atomic ratios (1:0.5, 1:1, and 1:1.5) that were synthesized on $\gamma$${\mathrm{-Al}}_2{\mathrm{O}}_3$ via sequential deposition–precipitation with urea. The catalysts were pretreated in either air or ${\mathrm{H}}_2$ and evaluated for CO oxidation activity and stability. A comprehensive characterization (EDS, BET, TEM, ${\mathrm{H}}_2$-TPR, ${\mathrm{O}}_2$-TPO, XPS, DRIFTS, and UV–Vis) was used to investigate particle size, metal oxidation states, and redox properties. Among all materials, the AuCu 1:1 catalyst exhibited the highest low-temperature CO conversion (>90% at 0 °C) and improved stability during 24 h tests, reflecting minimal nanoparticle sintering as confirmed by TEM analysis. In situ DRIFTS revealed that the presence of Cu⁺ and Cu²⁺ minimizes the accumulation of free carbonates (one of the main deactivation pathways in Au/$\gamma$${\mathrm{-Al}}_2{\mathrm{O}}_3$) while promoting the formation of reactive intermediates that facilitate ${\mathrm{CO}}_2$ production. Notably, air pretreatment at moderate temperature proved as effective as ${\mathrm{H}}_2$ pretreatment in activating both monometallic and bimetallic catalysts. These findings highlight the role of Cu as a structural and electronic promoter of gold, offering practical guidelines for designing durable, cost-effective catalysts for low-temperature CO oxidation on non-reducible supports. Full article

Iron-based catalysts for peroxymonosulfate (PMS) and peroxydisulfate (PDS) activation represent a cornerstone of advanced oxidation processes (AOPs) in environmental remediation, prized for their cost-effectiveness, environmental compatibility, and high catalytic potential. These catalysts, including zero-valent iron, iron oxides, and iron-organic frameworks, activate PMS/PDS through heterogeneous and homogeneous pathways to generate reactive species such as sulfate radicals (SO₄•⁻) and hydroxyl radicals (•OH). However, their large-scale implementation is constrained by inefficient iron cycling, characterized by sluggish Fe³⁺/Fe²⁺ conversion and significant iron precipitation, leading to catalyst passivation and oxidant wastage. This comprehensive review systematically dissects innovative strategies to augment iron cycling efficiency, encompassing advanced material design through elemental doping, heterostructure construction, and defect engineering; system optimization via reductant incorporation, bimetallic synergy, and pH modulation; and external field assistance using light, electricity, or ultrasound. We present a mechanistic deep-dive into these approaches, emphasizing facilitated electron transfer, suppression of iron precipitation, and precise regulation of radical versus non-radical pathways. The performance in degrading persistent organic pollutants—including antibiotics, per- and polyfluoroalkyl substances (PFASs), and pesticides—in complex environmental matrices is critically evaluated. We further discuss practical challenges related to scalability, long-term stability, and secondary environmental risks. Finally, forward-looking directions are proposed, focusing on rational catalyst design, integration of sustainable processes, and scalable implementation, thereby providing a foundational framework for developing next-generation iron-persulfate catalytic systems. Full article

Zeolitic imidazolate frameworks (ZIFs) can provide fascinating stereo morphology and tunable metal active sites, which plays an important role in the synthesis of various catalytic materials. However, it is still a problem to make use of these advantages to design efficient hydrogen evolution reaction (HER) catalysts. Herein, we use covalent coordination strategy to synthesize bimetallic Co_xZn_1−x(2-MeIM)₂ precursors with regular dodecahedral structures for providing uniform active sites and stable carbon skeleton. Furthermore, the ratio of Co and Zn atoms was optimized to balance the electron density and give full play to the synergistic catalytic effect. And then, the subsequent high temperature annealing process is used to construct the amorphous carbon layer, which can improve the overall stability of the material. The gas phase phosphating process realizes the transformation from ZIF material to metal phosphide resulting in enhanced hydrogen evolution activity. Finally, the optimized amorphous nitrogen-doped carbon (NC)-coated Zinc-doped cobalt phosphide (Zn_0.17Co_0.83P@NC) requires only 237.60 mV to reach the current density of 10 mA cm⁻² in alkaline medium, which is 223.22 mV lower than that of CoP, and has a stability of up to 18 h. This work provides a reference for the rational design of efficient and stable compound electrocatalysts for alkaline hydrogen evolution based on the bimetallic ZIF as a precursor. Full article