Nanoscale Particles Research Articles

Lithium modulated spinel high entropy oxide anode of LIBs through microwave solvothermal method

Spinel structured high entropy oxides (HEO) with three-dimensional Li+ transport channel and two different Wyckoff sites show high theoretical capacities due to multiple hypervalent ions and abundant oxygen vacancies. However, the intrinsic poor electrical conductivity of oxides and the lack of low-energy-consumption synthesis methods remain problems. Herein, Li+ with low-electronegativity is introduced into (FeCoNiCrMn)3O4 through high-efficiency microwave-assisted solvothermal method. The nano-scale high entropy oxide particles with homogeneous distribution of elements are successfully obtained in a short time. The addition of Li+ in HEO not only increases the valence states of transition metal cations to increase the number of electron transfers, but also induces more oxygen vacancies, which facilitates Li ion storage and increases ionic conductivity. The Li induced lattice distortion together with the entropy stabilization mechanism alleviate the lattice stress, featuring the anode superior electrochemical stability. The anode HEO-15 with the optimal Li content shows the specific capacity of 452.8 mAh g-1 at a current density of 500 mA g-1 after 300 cycles for LIBs, much higher than that of HEO-0 (248.9 mAh g-1). This research provides an effective method to improve the lithium storage performance of HEO.

Understanding magnetic interactions in SrFe12O19/CoFe2O4 nanocomposites: role of particle structure on exchange spring magnet behaviour

This study explores the impact of particle structure on the magnetic properties of SrFe12O19/CoFe2O4 nanocomposites. The investigation focuses on variations in particle sizes of SrFe12O19 (SHF) and CoFe2O4 (COF) with a mass ratio of 80:20, considering micro-scale poly-crystallite particles (Pp) and nano-scale mono-crystallite particles (Mp). Four sample structures (COM1, COM2, COM3, COM4) were prepared, each with different combinations of poly-crystallite and mono-crystallite particles. Morphological analysis through scanning electron microscopy and energy-dispersive x-ray spectroscopy revealed consistent grain shape and size post-sintering. Magnetic properties analysis using Permagraph indicated that grain fineness and uniformity influence the resulting magnetic properties, with composite samples featuring nano-sized hard or soft phases showing improved M r , M s , and (BH) max values compared to individual phases. The nanocomposite sample COM4, characterized by fine and uniform particle size, exhibited the highest remanence magnetization, M r (34.55 emu g−1), saturation magnetization, M s (66.44 emu g−1), and the maximum energy product, (BH) max (1.17 MGOe).

Cu Aerogel with Low Density, High Purity, and Oxidation Resistance for Bright X‐Ray Backlight

AbstractCu aerogel is an ideal material as the X‐ray backlight target in laser diagnosis experiments owing to its porous structure and K‐shell X‐ray emission spectrum. However, because of their poor formability and oxidation resistance, the preparation of pure Cu aerogels with nanoscale particles and pores is still difficult. In this study, a Cu aerogel is fabricated by reducing nanoporous Cu‐based aerogels and assembling Cu nanoparticles. Numerous pores ranging from 1 to 10 nm are present in the Cu aerogel, resulting in a spongy Cu aerogel for integral heating. Meanwhile, a metal passivation process is integrated into the fabrication process to prevent the oxidation of the Cu aerogel. The prepared Cu aerogel is then applied to the Shenguang‐II facility, improving integral heating when irradiated under high‐energy laser pulse irradiation. Compared with the high‐purity Cu foil reference target, the Cu aerogel target emitted nearly 18% more X‐ray energy on the K‐shell, and the noise in the L‐shell spectrum of Cu aerogel is largely restrained. These results indicate that the Cu aerogel is beneficial for the laser diagnostic experiments and essential for the X‐ray radiography in inertial confinement fusion experiments.

Electrodeposited Ni-Fe-TiO2 Alloy Composites for the Hydrogen Evolution Reaction

Hydrogen is a carbon-free alternative energy source that is environmentally friendly, has high energy density, and is a promising fuel for future generations. Water splitting is an efficient way to produce hydrogen, requiring a catalyst with a small overpotential and Tafel slope, and good stability. However, only 4 % of global hydrogen is produced by water electrolysis due to high cost and lack of inexpensive replacements of the active platinum electrocatalyst.1 However, replacing these noble metal electrocatalysts with those comprised of lower, earth-abundant elements remains challenging as these materials impart a higher overpotential and thus require higher energy. Guided by the recognised enhancements of TiO2 particles in Co-Mo alloys for HER, earth-abundant, low-cost Ni and Fe metals are examined as composite electrocatalysts Ni-Fe-TiO2 towards HER.2 Nano-scale TiO2 particles were embedded into Ni-Fe alloys by using galvanic and pulse-reverse electrodeposition, onto rotating cylinder electrodes. Pulse-reverse electrodeposition considerably increased the concentration of the particles incorporated into the alloy. The composition and morphology were characterized by X-ray fluorescence (XRF) spectroscopy and scanning electron microscopy (SEM), respectively. The addition of particles to the electrolyte affected both the deposit composition and morphology. The alloy composites were then used as electrocatalysts in 1 M KOH to characterize HER via linear sweep voltammetry on the resulting hydroxide surface. The surface area was examined in a ferri/ferrocyanide electrolyte. The polarization data in 1 M KOH shows a significant reduction in the HER overpotential when TiO2 particles are present in the Ni-Fe deposit. The surface analysis of Ni-Fe and Ni-Fe-TiO2 confirmed that the improvement in HER activity is not due to surface roughness but an intrinsic one. The stability of the electrocatalysts under an electrolysis for HER was examined at -10 mA/cm2 for 24 hr and the working electrode potential remained stable over time; Tafel polarization curves after electrolysis were similar to those prior to electrolysis. References Le, P. A., Trung, V. D., Nguyen, P. L., Phung, T. V. B., Natsuki, J., & Natsuki, T. RSC advances, 13(40), 28262-28287 (2023).C. Wang, H. K. Bilan, and E. J. Podlaha. J. Electrochem. Soc. 166 F661 (2019). C. Wang and E. J. Podlaha, J. Electrochem. Soc. 167, 132502 (1~4) (2020).

(Keynote) Macroscopic Materials Synthesized from Nanoparticle Superlattices

One of the promises of nanotechnology in its early developmental stages was the ability to make designer materials with precise control over individual building block composition and organization in 3D space. In recent years, material synthesis methods have advanced to be able to create a multitude of nanoparticles of varying sizes, shapes, and compositions, providing a vast array of building blocks to use as materials fabrication components. Additionally, processing methods have been developed to arrange these nanoparticles into ordered arrays, to dry them into thin films, and even to sinter them into more complex bulk solids. However, the fundamental promise of being able to build a material with controlled hierarchical structure across all length scales (atomic crystal structure, molecular composition; nanoscale feature size, shape, and organization; microstructure; macroscopic form) has been challenging to realize. A materials synthesis and processing route that could create free-standing, macroscopic materials or arbitrary three-dimensional shapes with precisely controlled nanoparticle positions across the entirety of the material composition would therefore be a major advancement. Here, we demonstrate a nanoparticle-based building block called a “Nanocomposite Tecton (NCT)” that enables a self-assembly route to fabricating free-standing 3D solids of arbitrary macroscopic shapes that can utilize a multitude of different nanoparticle compositions, and also possess specifically programmed nanoscale particle arrangements and controlled microstructure. This talk will outline the key synthesis and processing steps that enable this method of making materials with programmed material structure across ~7 orders of magnitude in length scale, thereby realizing a long-standing goal of nanomaterials fabrication.

Aluminum doped non-stoichiometric titanium dioxide as a negative electrode material for lithium-ion battery: In-operando XRD analysis

Lithium-ion batteries (LIB) with titanium dioxide as anode material emerged as one of the most energy-storage systems. In this study, we investigate aluminum-doped non-stoichiometric titanium dioxide synthesized using sol-gel method and subsequent reduction treatment. Different analysis techniques, such as X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) tests are conducted for the analysis of material and performance of the battery. The XRD results affirmed that the sample consisted of pure titanium-dioxide phases with no other precipitated phases, such as aluminum oxide (α-Al2O3 or γ-Al2O3). XPS analysis evident that aluminum was successfully incorporated into the titanium-dioxide lattice and the presence of Ti3+ and oxygen vacancy signals confirmed its non-stoichiometric nature. TEM images implies that doping and its extent did not significantly affect the size and morphology of the nanoscale particles. The selected area electron diffraction shows that the sample consisted of a mixture of the anatase and rutile phases. The best-performing electrode was found to be the one composed of 1 % aluminum-doped non-stoichiometric titanium dioxide. After 200 charge-discharge cycles, the battery maintained a capacity of 195 mAh/g, retaining 97.5 % of its reversible capacity. Cyclic stability test under high current condition shows that the capacity remained at 157 mAh/g without any noticeable decay after 750 charge-discharge cycles at a 1 C rate. This material exhibited the lowest impedance and the highest lithium-ion diffusion rate. Additionally, in situ synchrotron-based XRD indicates coexistence of three phases such as a new reversible intermediate phase LiTiO2, a partially irreversible intermediate phase Li0.55TiO2, and the anatase phase. The analysis results indicated that the peak intensities and angular shifts were associated with the phase changes that occurred during charge and discharge of the electrochemical processes. The interaction mechanism study between lithium ions and the lattice of mixed phase (anatase, rutile) identified the occurrence of non-uniform stress resulting from lithium-ion insertion in the rutile phase, in addition to the irreversible reactions in both the rutile and anatase phases. Through the synergistic effect of heteroatom doping and oxygen vacancy treatment, the conductivity of titanium dioxide is enhanced, leading to improved performance in capacity, impedance, cycle life, and rate as an anode material in LIBs.

Plant-Derived Extracellular Vesicles as a Novel Frontier in Cancer Therapeutics.

Recent advancements in nanomedicine and biotechnology have unveiled the remarkable potential of plant-derived extracellular vesicles (PDEVs) as a novel and promising approach for cancer treatment. These naturally occurring nanoscale particles exhibit exceptional biocompatibility, targeted delivery capabilities, and the capacity to load therapeutic agents, positioning them at the forefront of innovative cancer therapy strategies. PDEVs are distinguished by their unique properties that facilitate tumor targeting and penetration, thereby enhancing the efficacy of drug delivery systems. Their intrinsic biological composition allows for the evasion of the immune response, enabling the efficient transport of loaded therapeutic molecules directly to tumor sites. Moreover, PDEVs possess inherent anti-cancer properties, including the ability to induce cell cycle arrest and promote apoptotic pathways within tumor cells. These vesicles have also demonstrated antimetastatic effects, inhibiting the spread and growth of cancer cells. The multifunctional nature of PDEVs allows for the simultaneous delivery of multiple therapeutic agents, further enhancing their therapeutic potential. Engineering and modification techniques, such as encapsulation, and the loading of therapeutic agents via electroporation, sonication, and incubation, have enabled the customization of PDEVs to improve their targeting efficiency and therapeutic load capacity. This includes surface modifications to increase affinity for specific tumor markers and the encapsulation of various types of therapeutic agents, such as small molecule drugs, nucleic acids, and proteins. Their plant-derived origin offers an abundant and renewable source to produce therapeutic vesicles, reducing costs and facilitating scalability for clinical applications. This review provides an in-depth analysis of the latest research on PDEVs as emerging anti-cancer agents in cancer therapy.

Interfacial interactions of nanoscale zero-valent iron particles with clay minerals in the aquatic environments: Experimental and theoretical calculation study

The environmental transport and fate of nanoscale zero-valent iron particles (nZVI) in soil and groundwater can be altered by their hetero-aggregation with clay mineral particles (CMP). This study examines the interactions between bare or carboxymethyl cellulose (CMC)-coated nZVI with typical CMP, specifically kaolinite and montmorillonite. Methods include co-settling experiments, aggregation kinetic studies, electron microscopy, Derjaguin–Landau–Verwey–Overbeek (DLVO) and extended DLVO (EDLVO) energy analysis, and density functional theory calculations, focusing on the pH dependency of these interactions. The EDLVO theory effectively described the interactions between nZVI and CMP in aquatic environments. Under acidic conditions (pH 3.5), the interfacial interaction between bare nZVI and kaolinite is regulated by van der Waals forces, while complexation, van der Waals forces, and electrostatic attraction govern the interaction of bare nZVI with montmorillonite, primarily depositing on the SiO face. In contrast, the positively charged AlO face and edge of CMP are the main deposition sites for CMC-coated nZVI through hydrogen bonding, van der Waals forces, and electrostatic attraction. At neutral (pH 6.5) and alkaline (pH 9.5) conditions, both bare and CMC-coated nZVI predominantly attach to the AlO face and edge, facilitated by complexation or hydrogen bonding, alongside van der Waals forces. The attachment of CMC-coated nZVI to CMP surfaces shows reversible aggregation or deposition due to the steric repulsion from the CMC coating. These findings hold significant implications for the environmental applications and risk of nZVI.

Folate receptor-targeted indomethacin-loaded gold nanoparticles enhance drug chemotherapeutic efficacy in glioblastoma cells and spheroids

Glioblastoma is a highly malignant brain cancer with a poor survival rate. Increasing evidence demonstrates the anticancer activity, including anti-glioma activity, of indomethacin (IND), a non-steroidal anti-inflammatory drug. However, due to the IND's poor aqueous solubility, nano-based drug delivery systems, especially gold nanoparticles (AuNPs), are great tools for increasing solubility and therapeutic efficacy. Herein, glutathione (GSH)-coated folic acid (FA)-modified AuNPs were used for the first time to generate IND-loaded AuNPs (55 nm), which were successfully synthesized according to DLS, TEM, FTIR, NMR, and TGA results. IND/AuNPs were found to have spherical morphology, nanoscale particle size, narrow size distribution, and good stability. Fluorescence and confocal imaging demonstrated that the nanoparticles penetrated folate receptor (FR)+ U-87MG human glioblastoma monolayer and sphere-forming cells. Remarkably, short-term exposure (4h) to IND/AuNPs significantly increased IND cytotoxicity in U-87MG cells after post-44h and -68h (>35- and >120-fold, respectively). Even against prolonged exposure of cells to IND for 24h, 48h, and 72h, IND/AuNP treatment revealed a marked result: glioma proliferation slowed by 7.38-fold, 6.8-fold, and 17-fold, respectively. No significant effect was observed on the FR− cell lines. The increased antitumoral activity was accompanied by efficient increased apoptosis in glioblastoma cells due to the IND/AuNP treatments. Moreover, compared to free-drug and control groups, IND/AuNP treatments markedly reduced glioblastoma growth in 3D spheroids (in vitro system that mimics in vivo tumors). Therefore, these findings suggest that the new spherical IND/Au-GSH-FA NP conjugate has the potential to be a beneficial therapeutic agent in glioblastoma therapy by targeting FRs.

An investigation of nano- and micron-sized carriers based on calcium carbonate and polylactic acid for oral administration of siRNA

ABSTRACT Background Oral delivery of small interfering RNAs (siRNAs) draws significant attention, but the gastrointestinal tract (GIT) has many biological barriers that limit the drugs’ bioavailability. The aim of this work was to investigate the potential of micro- and nano-sized CaCO3 and PLA carriers for oral delivery of siRNA and reveal a relationship between the physicochemical features of these carriers and their biodistribution. Research design and methods In vitro stability of carriers was investigated in simulated gastric and intestinal fluids. Toxicity and cellular uptake were investigated on Caco-2 cells. The biodistribution profiles of the developed CaCO3 and PLA carriers were examined using different visualization methods, including SPECT, fluorescence imaging, radiometry, and histological analysis. The delivery efficiency of siRNA loaded carriers was investigated both in vitro and in vivo. Results Micro-sized carriers were accumulated in the stomach and later localized in the colon tissues. The nanoscale particles (100–250 nm) were distributed in the colon tissues. nPLA was also detected in small intestine. The developed carriers can prevent siRNA from premature degradation in GIT media. Conclusion Our results reveal how the physicochemical properties of the particles, including their size and material type can affect their biodistribution profile and oral delivery of siRNA.

Toward an Understanding of Uric Acid Particle Dissolution: Surface and Bulk-Driven Water Activity.

Uric acid particles contribute to kidney stones, and natural processes for the elimination of stones depend on solute-solvent interactions. The process of uric acid dissolution has previously been understood via the lens of solubility; however, for pure and mixed salt solutions, these approaches do not provide a comprehensive picture of nanoscale particle solution thermodynamics. Unlike solubility measurements, water activity measurements provide us with information about the chemical potential responsible for the migration of water molecules driving the dissolution of particles. In this work, we used in situ experimental tools to estimate water activity values for pure uric acid aqueous droplets at different stages of droplet growth. The process of cloud formation, i.e., water condensation on a solute particle resulting in aqueous droplet formation, was leveraged to compare the water affinity for nanosized uric acid particles with a well-studied inorganic salt, sodium chloride. Specifically, we investigated microscopic uric acid particles (nanoparticles <300 nm, amorphous and super micron particles >5 μm, crystalline) and the mechanism of water uptake. The growth of droplet volume (Growth Factor, GF) for uric acid particles is experimentally observed for supermicrometer crystalline particles (>1 μm) at subsaturated humidity conditions (<100% RH). In addition, the water activity of submicrometer-size uric acid particles is estimated under subsaturated and supersaturated humidity conditions. These measurements provide us with information about the volume growth of droplets as water condenses in particles exposed to different humidity conditions. Our observations under subsaturated humidity conditions show that the uric acid particles have limited volume growth (<1% change per volume and <10% change per volume for crystalline and amorphous measurement, respectively). From the experimental data, the affinity of uric acid solute with water as a solvent is quantified in terms of water activity.

Numerical Derivation of Dual Vortex Beam Generation using Polarization‐Sensitive Dielectric Metasurfaces

AbstractMetasurfaces, composed of arranged nanoscale particles, manipulate electromagnetic waves for tailored physical properties. Recently vortex beams, carrying orbital angular momentum, have been generated through metasurfaces to realize diverse applications. Here, the study introduces a metasurface capable of generating dual‐mode vortex beams, which combines the functionalities of chiral metalenses and vortex beam generation. These dual‐mode vortex beams exhibit varying characteristics depending on the polarization state of the incident light, offering improved control over orbital angular momentum. This advancement holds promise for enhancing applications such as optical communication, optical tweezers, and imaging for overcoming diffraction limit. By employing titanium dioxide (TiO2) for its efficiency, the design concept is validated through simulations and discuss considerations for fabrication. The proposed approach paves the way for compact optical systems with heightened adaptability.

Gallium complexation for DO3A coated nanoparticles: a comprehensive study

This review provides a comprehensive review of the synthesis and utilization of DO3A-functionalized NPs (Particularly for MRI and PET/CT analysis). The main focus of the study is the formation of a complex of gallium with NPs coated with DO3A, as well as showing the possibility of improving contrast agents and creating new gallium-based nanomaterials for medical use. The synthesis process studies parameters like pH, temperature, and the effect of substitution of the ligand using various chemical analysis techniques to determine the physicochemical properties of these nano-scale particles. This implies that gallium-loaded NPs have the potential to enhance the fight against infectious diseases, as proved by the NPs' vital role in antimicrobial therapies for PET imaging. Research with animals has shown significant biodistribution to the organs and tissues of interest, which have helped enhance the imaging features of MRI and PET/CT scans. Likewise, the findings on biocompatibility and toxicity point to possible clinical application of these nanoparticles. As for future research directions, the synthesis of other new derivatives of Gd-DO3A complexes containing lipophilic monoamides and the examination of ionization's influence on encapsulation efficiency have been mentioned. This review stresses the promising use of DO3A-coated nanoparticles for nanomedicine as therapeutic agents or imaging probes.

Plant Extracts for Production of Functionalized Selenium Nanoparticles.

In recent years, selenium nanoparticles (SeNPs) have attracted expanding consideration, particularly in the nanotechnology field. This element participates in important biological processes, such as antioxidant defense, immune function, and thyroid hormone regulation, protecting cells from oxidative damage. Selenium in the form of nanoscale particles has drawn attention for its biocompatibility, bioavailability, and low toxicity; thus, it has found several biomedical applications in diagnosis, treatment, and monitoring. Green methods for SeNP synthesis using plant extracts are considered to be single-step, inexpensive, and eco-friendly processes. Besides acting as natural reductants, compounds from plant extracts can also serve as natural capping agents, stabilizing the size of nanoparticles and contributing to the enhanced biological properties of SeNPs. This brief overview presents the recent developments in this area, focusing on the synthesis conditions and the characteristics of the obtained SeNPs.

Microstructures and High-Temperature Mechanical Properties of Inconel 718 Superalloy Fabricated via Laser Powder Bed Fusion.

The Inconel 718 superalloy demonstrates the potential to fabricate high-temperature components using additive manufacturing. However, additively manufactured Inconel 718 typically exhibits low strength, necessitating post-heat treatments for precipitate strengthening. This study investigated the microstructures and mechanical properties of the Inconel 718 superalloy fabricated via laser powder bed fusion. The room-temperature and high-temperature tensile properties of the Inconel 718 alloy samples following various post-heat treatments were evaluated. The results indicate that the as-built samples exhibited columnar grains with fine cell structures. Solution treatment resulted in δ phase formation and grain recrystallization. Subsequent double aging led to finely distributed nanoscale γ' and γ″ particles. These nanoscale particles provided high strength at both room and high temperatures, resulting in a balanced strength and ductility comparable to the wrought counterpart. High-temperature nanoindentation analyses revealed that the double-aging samples exhibited very high hardness and low creep rates at 650 °C.

A supramolecular method to control protein assembly using a biogenic polyamine

ABSTRACT We report a method to modulate the formation and stability of nano- and micro-assemblies of bovine serum albumin (BSA) formed with CB[7] using the treatment of a biogenic polyamine such as spermine (SPM). Our findings show that SPM impacts the size and surface charge of BSA-CB[7] assemblies, effectively reducing the size of nanoscale particles and making their surface charges more positive. Conversely, for larger particles spanning more than a few micrometres in diameter, SPM treatment is less effective in reducing their size. This ineffectiveness is attributed to the interaction between the external surface of CB[7] and BSA, which remains relatively unaffected by SPM. Over time, with an excess of CB[7], this interaction becomes more pronounced, resulting in aggregation of large particles and subsequent sedimentation. Since SPM is a biogenic polyamine found at elevated levels in cancerous tissues, this result may offer a strategic direction for designing supramolecular systems to control protein assemblies in oncological environments, highlighting the significant potential of supramolecular chemistry in biomedical applications.

Passivation Behavior of Chromium Alloyed High-Strength Rebar in Simulated Concrete Pore Solution

In this study, SEM, AFM, TEM, XPS, and electrochemical tests are used to study the passivation behavior of chromium alloyed high-strength rebar in simulated concrete pore (SCP) solutions with different pH values. The results show that after passivation in SCP solution with different pH values, the passivating film on the surface of the chromium alloyed rebar primarily consists of a layer of nanoscale oxide particles, which makes the passive film exhibit a p-n type semi-conductor, and the passive film presents a rhombohedral crystal structure. As the pH value of the SCP solution decreases, the nanoscale oxide particles on the surface of the rebar become denser, which leads to a reduction in the carrier density (Nq and Na) of the passive film and an increase in film resistance (R2) and charge transfer resistance (R3), thus increasing the corrosion resistance of the passive film. The passive film on the surface of the chromium alloyed high-strength rebar predominantly exhibits a three-layer structure, the outer passive film layer is composed of Fe oxides, the stable layer of the passive film is composed of Fe oxides and Cr oxides, and the growth layer of inner passive film is composed of Cr oxides. Compared with passivation 10 d in SCP solutions with pH 13.5 and pH 12.5, the passive film on the surface of the rebar has good stability at pH 10.5, which indicates that the addition of Cr is beneficial to promote the corrosion resistance of the rebar.

Electrochemical Performance of a Hybrid NiCo2O4@NiFelt Electrode at Different Operating Temperatures and Electrolyte pH

Transition metals such as nickel and cobalt as an alternative to Pt and Pd can be used for oxygen evolution reactions (OERs) and hydrogen production reactions (HERs) in alkaline environments, facilitating green hydrogen production as a sustainable alternative to fossil fuels. In this study, an NiCo2O4 catalyst was produced by a sono-hydrothermal method using urea as a hydrolysis agent. The electrochemical performance of the catalyst-coated NiFelt electrode was evaluated at different KOH concentrations (0.25, 0.5, and 1 M) and four operating temperatures in the interval of 20–80 °C. The electrode characteristics were investigated via electrochemical spectroscopy (cyclic voltammetry, EIS, multistep chronopotentiometry, multistep chronoamperometry) using two different reference electrodes (Ag/AgCl and Hg/HgO), to obtain insight into the anodic and cathodic peaks. XRD, SEM, EDS, and TEM analyses confirmed the purity, structure, and nanoscale particle size (20–45 nm) of the NiCo2O4 catalyst. The electrode showed symmetric CV with Ag/AgCl, making this reference electrode more appropriate for capacitance measurements, while Hg/HgO proved advantageous for EIS in alkaline solutions due to reduced noise. The overpotential of the catalyst-coated NiFelt decreased by 108 mV at 10 mA/cm2 compared to bare NiFelt, showing a good potential for its application in anion exchange membranes and alkaline electrolyzers at an industrial scale.

A multi-layer membrane filter made of potassium catalyst and three-way catalyst for a passive after-treatment system

A multi-layer membrane has been fabricated to integrate a Three-Way Catalyst (TWC) and Gasoline Particulate Filter (GPF) into one device, called a four-way catalytic converter. The top layer, made of nano-scale potassium catalyst particles, traps Particulate Matter (PM) with almost 100% filtration efficiency at all times and oxidizes PM (mostly soot) with a significantly reduced temperature of 476°C at the oxidation peak. Moreover, the bottom layer catalyst is comprised of sub-micro TWC particles to combine NO reduction and CO oxidation capabilities. The effective temperature range for the simultaneous removal of all pollutants was between 420°C–500°C.

Oxide precipitation strengthening in Cu alloy modified with trace amounts of Nd during dynamic impact

In this study, three kinds of Cu-Nd alloys were prepared. The effect of Nd content on the dynamic impact behavior of the Cu-Nd alloys and its strengthening mechanism were studied. The results show that during the dynamic impact process, nano-scale oxide particles are precipitated in the alloy matrix, and a large number of cracks are formed along the grain boundaries, and the formation of shear bands and thermal grooves are also observed in local areas. With the increase of Nd content, the compressive strength of the alloys increases significantly, the grain size is refined, the number of twins increases, the grooves are much deeper and the number of the precipitated nano-oxide particles also increase significantly. In addition, due to the refinement of the grain size, the crack length is reduced. The increase of the alloy strength is mainly attributed to the nano-scale oxide precipitation strengthening and grain refinement strengthening.