Discover Top Posts Tagged with #core shell structures

Sprinkling nanoparticles on spintronics

Today, I want to walk you through a deceptively simple innovation from the lab at Loughborough University (PI: Prof Marco Peccianti): what happens when we decorate a spintronic heterostructure with a sparse layer of plasmonic nanoparticles? This isn't just a lab curiosity—it's a step toward making terahertz sources more efficient, compact, and practical for real-world applications like high-speed communications, noninvasive imaging, and advanced spectroscopy. Spintronic THz emitters: The foundation Spintronic terahertz emitters rely on a thin, multilayer stack—typically heavy metal like tungsten (W), a ferromagnetic layer such as iron (Fe), and a platinum (Pt) cap. A femtosecond laser pulse strikes the structure, rapidly heating electrons and generating a pure spin current through spin-orbit torque effects.

Iron core-shell catalyst boosts hydrogen economy of direct syngas to olefin conversion

Scientists have developed a new iron-based catalyst that improves the typically low hydrogen atom economy (HAE) in the direct synthesis of olefins—small hydrocarbon molecules. It converts the water produced as a by-product into hydrogen for olefin production, thereby boosting overall efficiency. Olefins derived from petroleum are the building blocks for many plastics and fuels. Direct conversion of syngas—a mixture of carbon monoxide (CO) and hydrogen (H2)—into olefins offers a promising alternative to reducing reliance on petroleum. It opens ways for using syngas derived from coal, biomass, or natural gas as a feedstock for olefin production. In this study published in Science, researchers presented a sodium-modified FeCx@Fe3O4 core-shell catalyst produced via coprecipitation and thermal treatment. The catalyst achieved over 75% olefin selectivity and a 33% by weight hydrocarbon yield. It also had an HAE of ~66–86%, which is significantly higher than the ~43–47% seen in the traditional syngas-to-olefin (STO) conversion methods.

Metallic nanocatalysts: What really happens during catalysis

Using a combination of spectromicroscopy at BESSY II and microscopic analyses at DESY's NanoLab, a team has gained new insights into the chemical behavior of nanocatalysts during catalysis. The research is published in the journal ACS Nano. The nanoparticles consisted of a platinum core with a rhodium shell. This configuration allows a better understanding of structural changes in, for example, rhodium–platinum catalysts for emission control. The results show that under typical catalytic conditions, some of the rhodium in the shell can diffuse into the interior of the nanoparticles. However, most of it remains on the surface and oxidizes. This process is strongly dependent on the surface orientation of the nanoparticle facets. Nanoparticles measure less than one ten-thousandth of a millimeter in diameter and have enormous surface areas in relation to their mass. This makes them attractive as catalysts: metallic nanoparticles can facilitate chemical conversions, whether for environmental protection, industrial synthesis or the production of (sustainable) fuels from CO2 and hydrogen.

Novel nanowire catalyst could help advance hydrogen production technology

Researchers at Beijing University of Technology have developed a new type of acid-stable bimetallic phosphide-silver core-shell nanowire catalyst that significantly improves the efficiency of the hydrogen evolution reaction (HER). Their findings, published in Frontiers in Energy, offer promising insights into advancing hydrogen production technologies. Hydrogen production through proton exchange membrane water electrolysis is a crucial step toward sustainable energy solutions. However, the development of cost-effective and efficient electrocatalysts that can withstand acidic conditions remains a significant challenge. Traditional non-noble metal catalysts often fall short in performance and durability when exposed to harsh acidic environments.

High heat dissipation design improves thermal protection on ultrahigh temperature ablation

ZrC has drawn wide attention as an anti-ablation coating material for lightweight C/C composites but is limited by the produced porous and loose ZrO2 film. To address this issue, the second phase is introduced to improve the densification of the formed Zr-X-O film. Such as ZrC-SiC/TaC coating, the produced low-melting-point oxides, SiO2 (Tm=1650 °C), Ta2O5 (Tm=1800 °C) and Zr6Ta2O17 (Tm=1900 °C), helped to form a dense oxides film. However, the high service temperature causes heat accumulation and a large thermal stress gradient on the surface of the coatings, which will result in large local defects and accelerate the failure of the coating.

Core-shell structural units show outstanding toughening effect for ceramics

Toughening has always been an important research direction of structure ceramics. The addition of secondary phases to the ceramic matrix to prepare composite ceramics is an effective toughening pathway in the field of structure ceramics. Both phase-type and microstructure of the secondary phases play a decisive role in the toughening effect of the ceramic matrix. Being different from the conventional independent phase as the secondary phase, B4C@TiB2 core–shell structural unit has been purposely designed as an innovative kind of secondary phase to toughen the Al2O3 ceramic matrix, providing a new concept for the toughening studies of structural ceramics. A team of material scientists led by Zhixiao Zhang from the Hebei University of Engineering in Handan, China recently successfully prepared a kind of Al2O3 composite ceramics toughened by B4C@TiB2 core–shell structural units consisting of the B4C core enclosed by the TiB2 shell.

Nanocrystals set new hydrogen production activity record under visible and near-infrared irradiation

The sunlight received by Earth is a mixed bag of wavelengths ranging from ultraviolet to visible to infrared. Each wavelength carries inherent energy that, if effectively harnessed, holds great potential to facilitate solar hydrogen production and diminish reliance on non-renewable energy sources. Nonetheless, existing solar hydrogen production technologies face limitations in absorbing light across this broad spectrum, particularly failing to harness the potential of near infrared (NIR) light energy that reaches Earth. Recent research has identified that both Au and Cu7S4 nanostructures exhibit a distinctive optical characteristic known as localized surface plasmon resonance (LSPR).

Researchers reveal ways to fine-tune nanoparticles and outline future areas of study

The demand for renewable energy sources is constantly growing fueling the development of catalytic-based technologies. By separating and forming chemical bonds, these technologies can be used to produce environmentally friendly energy. In recent decades, researchers have been actively studying how core-shell nanoparticles can improve the performance of catalytic systems, which mainly use metal catalysts that accelerate chemical reactions. Researchers from Skoltech analyzed the latest achievements in synthesizing core-shell particles, research methods, techniques for adjusting their properties, and also identified the most promising areas for future research. A large review has been published in Nanoscale.

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