Structural Regulation of Au-Pt Bimetallic Aerogels for Catalyzing the Glucose Cascade Reaction.

Bimetallic nanostructures are promising candidates for the development of enzyme-mimics, yet the deciphering of the structural impact on their catalytic properties poses significant challenges. By leveraging the structural versatility of nanocrystal aerogels, this study reports a precise control of Au-Pt bimetallic structures in three representative structural configurations, including segregated, alloy, and core-shell structures. Benefiting from a synergistic effect, these bimetallic aerogels demonstrate improved peroxidase- and glucose oxidase-like catalytic performances compared to their monometallic counterparts, unleashing tremendous potential in catalyzing the glucose cascade reaction. Notably, the segregated Au-Pt aerogel shows optimal catalytic activity, which is 2.80 and 3.35 times higher than that of the alloy and core-shell variants, respectively. This enhanced activity is attributed to the high-density Au-Pt interface boundaries within the segregated structure, which foster greater substrate affinity and superior catalytic efficiency. This work not only sheds light on the structure-property relationship of bimetallic catalysts but also broadens the application scope of aerogels in biosensing and biological detections.

Investigating the interaction of uranium(VI) with diatoms and their bacterial community: A microscopic and spectroscopic study.

Diatoms and bacteria play a vital role in investigating the ecological effects of heavy metals in the environment. Despite separate studies on metal interactions with diatoms and bacteria, there is a significant gap in research regarding heavy metal interactions within a diatom-bacterium system, which closely mirrors natural conditions. In this study, we aim to address this gap by examining the interaction of uranium(VI) (U(VI)) with Achnanthidium saprophilum freshwater diatoms and their natural bacterial community, primarily consisting of four successfully isolated bacterial strains (Acidovorax facilis, Agrobacterium fabrum, Brevundimonas mediterranea, and Pseudomonas peli) from the diatom culture. Uranium (U) bio-association experiments were performed both on the xenic A. saprophilum culture and on the four bacterial isolates. Scanning electron microscopy and transmission electron microscopy coupled with spectrum imaging analysis based on energy-dispersive X-ray spectroscopy revealed a clear co-localization of U and phosphorus both on the surface and inside A. saprophilum diatoms and the associated bacterial cells. Time-resolved laser-induced fluorescence spectroscopy with parallel factor analysis identified similar U(VI) binding motifs both on A. saprophilum diatoms and the four bacterial isolates. This is the first work providing valuable microscopic and spectroscopic data on U localization and speciation within a diatom-bacterium system, demonstrating the contribution of the co-occurring bacteria to the overall interaction with U, a factor non-negligible for future modeling and assessment of radiological effects on living microorganisms.

Optical Thin Films in Space Environment: Investigation of Proton Irradiation Damage.

The present work reports a systematic study of the potential degradation of metals and dielectric thin films in different space environments. The mono- and bilayers selected are made of materials commonly used for the realization of optical components, such as reflective mirrors or building blocks of interferential filters. More than 400 samples were fabricated and irradiated with protons at different energies on ground-based facilities. The fluences were selected as a result of simulations of the doses delivered within a long-term space mission considering different orbits (Sun close, Jovian, and Geostationary orbits). In order to stress the samples at different depths and layer interfaces, experiments were carried out with a range of proton energies within 1 and 10 MeV values. An estimate of a safe maximum fluence has been provided for each type of sample at each energy. The damage mechanism, when present, has been investigated with different optical and structural techniques.

At the Limit of Interfacial Sharpness in Nanowire Axial Heterostructures.

As semiconductor devices approach dimensions at the atomic scale, controlling the compositional grading across heterointerfaces becomes paramount. Particularly in nanowire axial heterostructures, which are promising for a broad spectrum of nanotechnology applications, the achievement of sharp heterointerfaces has been challenging owing to peculiarities of the commonly used vapor-liquid-solid growth mode. Here, the grading of Al across GaAs/AlxGa1-xAs/GaAs heterostructures in self-catalyzed nanowires is studied, aiming at finding the limits of the interfacial sharpness for this technologically versatile material system. A pulsed growth mode ensures precise control of the growth mechanisms even at low temperatures, while a semiempirical thermodynamic model is derived to fit the experimental Al-content profiles and quantitatively describe the dependences of the interfacial sharpness on the growth temperature, the nanowire radius, and the Al content. Finally, symmetrical Al profiles with interfacial widths of 2-3 atomic planes, at the limit of the measurement accuracy, are obtained, outperforming even equivalent thin-film heterostructures. The proposed method enables the development of advanced heterostructure schemes for a more effective utilization of the nanowire platform; moreover, it is considered expandable to other material systems and nanostructure types.

Multi-Level Switching of Spin-Torque Ferromagnetic Resonance in 2D Magnetite.

2D magnetic materials hold substantial promise in information storage and neuromorphic device applications. However, achieving a 2D material with high Curie temperature (TC), environmental stability, and multi-level magnetic states remains a challenge. This is particularly relevant for spintronic devices, which require multi-level resistance states to enhance memory density and fulfil low power consumption and multi-functionality. Here, the synthesis of 2D non-layered triangular and hexagonal magnetite (Fe3O4) nanosheets are proposed with high TC and environmental stability, and demonstrate that the ultrathin triangular nanosheets show broad antiphase boundaries (bAPBs) and sharp antiphase boundaries (sAPBs), which induce multiple spin precession modes and multi-level resistance. Conversely, the hexagonal nanosheets display slip bands with sAPBs associated with pinning effects, resulting in magnetic-field-driven spin texture reversal reminiscent of "0" and "1" switching signals. In support of the micromagnetic simulation, direct explanation is offer to the variation in multi-level resistance under a microwave field, which is ascribed to the multi-spin texture magnetization structure and the randomly distributed APBs within the material. These novel 2D magnetite nanosheets with unique spin textures and spin dynamics provide an exciting platform for constructing real multi-level storage devices catering to emerging information storage and neuromorphic computing requirements.

Spin Effect to Regulate the Electronic Structure of Ir─Fe Aerogels for Efficient Acidic Water Oxidation.

"Spin" has been recently reported as an important degree of electronic freedom to promote catalysis, yet how it influences electronic structure remains unexplored. This work reports the spin-induced orbital hybridization in Ir─Fe bimetallic aerogels, where the electronic structure of Ir sites is effectively regulated by tuning the spin property of Fe atoms. The spin-optimized electronic structure boosts oxygen evolution reaction (OER) electrocatalysis in acidic media, resulting in a largely improved catalytic performance with an overpotential of as low as 236 mV at 10 mA cm-2. Furthermore, the gelation kinetics for the aerogel synthesis is improved by an order of magnitude based on the introduction of a magnetic field. Density functional theory calculation reveals that the increased magnetic moment of Fe (3d orbital) changes the d-band structure (i.e., the d-band center and bandwidth) of Ir (5d orbital) via orbital hybridization, resulting in optimized binding of reaction intermediates. This strategy builds the bridge between the electron spin theory with the d-band theory and provides a new way for the design of high-performance electrocatalysts by using spin-induced orbital interaction.

Cobalt-based Co3Mo3N/Co4N/Co Metallic Heterostructure as a Highly Active Electrocatalyst for Alkaline Overall Water Splitting.

Alkaline water electrolysis holds promise for large-scale hydrogen production, yet it encounters challenges like high voltage and limited stability at higher current densities, primarily due to inefficient electron transport kinetics. Herein, a novel cobalt-based metallic heterostructure (Co3Mo3N/Co4N/Co) is designed for excellent water electrolysis. In operando Raman experiments reveal that the formation of the Co3Mo3N/Co4N heterointerface boosts the free water adsorption and dissociation, increasing the available protons for subsequent hydrogen production. Furthermore, the altered electronic structure of the Co3Mo3N/Co4N heterointerface optimizes ΔGH of the nitrogen atoms at the interface. This synergistic effect between interfacial nitrogen atoms and metal phase cobalt creates highly efficient active sites for the hydrogen evolution reaction (HER), thereby enhancing the overall HER performance. Additionally, the heterostructure exhibits a rapid OH- adsorption rate, coupled with great adsorption strength, leading to improved oxygen evolution reaction (OER) performance. Crucially, the metallic heterojunction accelerates electron transport, expediting the afore-mentioned reaction steps and enhancing water splitting efficiency. The Co3Mo3N/Co4N/Co electrocatalyst in the water electrolyzer delivers excellent performance, with a low 1.58 V cell voltage at 10 mA cm-2, and maintains 100 % retention over 100 hours at 200 mA cm-2, surpassing the Pt/C||RuO2 electrolyzer.

Low-temperature diffusion in thin-film Pt-(Au-)-Co heterostructures: a structural and magnetic characterization.

Formation of functional thin films for nanoelectronics and magnetic data storage via thermally induced diffusion-driven structural phase transformations in multilayer stacks is a promising technology-relevant approach. Ferromagnetic thin films based on Co Pt alloys are considered as a material science platform for the development of various applications such as spin valves, spin orbit torque devices, and high-density data storage media. Here, we study diffusion processes in Pt-Co-based stacks with the focus on the effect of layers inversion (Pt/Co/substrate versus Co/Pt/substrate) and insertion of an intermediate Au layer on the structural transitions and magnetic properties. We demonstrate that the layer stacking has a pronounced effect on the diffusion rate at temperatures, where the diffusion is dominated by grain boundaries. We quantify effective diffusion coefficients, which characterize the diffusion rate of Co and Pt through the interface and grain boundaries, providing the possibility to control the homogenization rate of the Pt-Co-based heterostructures. The obtained values are in the range of 10-16-10-13cm2s-1for temperatures of 150 °C-350 °C. Heat treatment of the thin-film samples results in the coercivity enhancement, which is attributed to short-range chemical ordering effects. We show that introducing an additional Au intermediate layer leads to an increase of the coercive field of the annealed samples due to a modification of exchange coupling between the magnetic grains at the grain boundaries.

Complete Glucose Electrooxidation Enabled by Coordinatively Unsaturated Copper Sites in Metal-Organic Frameworks.

The electrocatalytic oxidation of glucose plays a vital role in biomass conversion, renewable energy, and biosensors, but significant challenges remain to achieve high selectivity and high activity simultaneously. In this study, we present a novel approach for achieving complete glucose electrooxidation utilizing Cu-based metal-hydroxide-organic framework (Cu-MHOF) featuring coordinatively unsaturated Cu active sites. In contrast to traditional Cu(OH)2 catalysts, the Cu-MHOF exhibits a remarkable 40-fold increase in electrocatalytic activity for glucose oxidation, enabling exclusive oxidation of glucose into formate and carbonate as the final products. The critical role of open metal sites in enhancing the adsorption affinity of glucose and key intermediates was confirmed by control experiments and density functional theory simulations. Subsequently, a miniaturized nonenzymatic glucose sensor was developed showing superior performance with a high sensitivity of 214.7 µA mM-1 cm-2 , a wide detection range from 0.1 µM to 22 mM, and a low detection limit of 0.086 µM. Our work provides a novel molecule-level strategy for designing catalytically active sites and could inspire the development of novel metal-organic framework for next-generation electrochemical devices.

Structural investigations of Au-Ni aerogels: morphology and element distribution.

The physical properties of nanomaterials are determined by their structural features, making accurate structural control indispensable. This carries over to future applications. In the case of metal aerogels, highly porous networks of aggregated metal nanoparticles, such precise tuning is still largely pending. Although recent improvements in controlling synthesis parameters like electrolytes, reductants, or mechanical stirring, the focus has always been on one particular morphology at a time. Meanwhile, complex factors, such as morphology and element distributions, are studied rather sparsely. We demonstrate the capabilities of precise morphology design by deploying Au-Ni, a novel element combination for metal aerogels in itself, as a model system to combine common aerogel morphologies under one system for the first time. Au-Ni aerogels were synthesized via modified one- and two-step gelation, partially combined with galvanic replacement, to obtain aerogels with alloyed, heterostructural (novel metal aerogel structure of interconnected nanoparticles and nanochains), and hollow spherical building blocks. These differences in morphology are directly reflected in the physisorption behavior, linking the isotherm shape and pore size distribution to the structural features of the aerogels, including a broad-ranging specific surface area (35-65 m2 g-1). The aerogels were optimized regarding metal concentration, destabilization, and composition, revealing some delicate structural trends regarding the ligament size and hollow sphere character. Hence, this work significantly improves the structural tailoring of metal aerogels and possible up-scaling. Lastly, preliminary ethanol oxidation tests demonstrated that morphology design extends to the catalytic performance. All in all, this work emphasizes the strengths of morphology design to obtain optimal structures, properties, and (performances) for any material application.

Ferromagnetic Interlayer Coupling in CrSBr Crystals Irradiated by Ions.

Layered magnetic materials are becoming a major platform for future spin-based applications. Particularly, the air-stable van der Waals compound CrSBr is attracting considerable interest due to its prominent magneto-transport and magneto-optical properties. In this work, we observe a transition from antiferromagnetic to ferromagnetic behavior in CrSBr crystals exposed to high-energy, non-magnetic ions. Already at moderate fluences, ion irradiation induces a remanent magnetization with hysteresis adapting to the easy-axis anisotropy of the pristine magnetic order up to a critical temperature of 110 K. Structure analysis of the irradiated crystals in conjunction with density functional theory calculations suggests that the displacement of constituent atoms due to collisions with ions and the formation of interstitials favors ferromagnetic order between the layers.

Europium(III) as luminescence probe for interactions of a sulfate-reducing microorganism with potentially toxic metals.

Microorganisms show a high affinity for trivalent actinides and lanthanides, which play an important role in the safe disposal of high-level radioactive waste as well as in the mining of various rare earth elements. The interaction of the lanthanide Eu(III) with the sulfate-reducing microorganism Desulfosporosinus hippei DSM 8344T, a representative of the genus Desulfosporosinus that naturally occurs in clay rock and bentonite, was investigated. Eu(III) is often used as a non-radioactive analogue for the trivalent actinides Pu(III), Am(III), and Cm(III), which contribute to a major part of the radiotoxicity of the nuclear waste. D. hippei DSM 8344T showed a weak interaction with Eu(III), most likely due to a complexation with lactate in artificial Opalinus Clay pore water. Hence, a low removal of the lanthanide from the supernatant was observed. Scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy revealed a bioprecipitation of Eu(III) with phosphates potentially excreted from the cells. This demonstrates that the ongoing interaction mechanisms are more complex than a simple biosorption process. The bioprecipitation was also verified by luminescence spectroscopy, which showed that the formation of the Eu(III) phosphate compounds starts almost immediately after the addition of the cells. Moreover, chemical microscopy provided information on the local distribution of the different Eu(III) species in the formed cell aggregates. These results provide first insights into the interaction mechanisms of Eu(III) with sulfate-reducing bacteria and contribute to a comprehensive safety concept for a high-level radioactive waste repository, as well as to a better understanding of the fate of heavy metals (especially rare earth elements) in the environment.

Novel Mixed-Dimensional hBN-Passivated Silicon Nanowire Reconfigurable Field Effect Transistors: Fabrication and Characterization.

This work demonstrates the novel concept of a mixed-dimensional reconfigurable field effect transistor (RFET) by combining a one-dimensional (1D) channel material such as a silicon (Si) nanowire with a two-dimensional (2D) material as a gate dielectric. An RFET is an innovative device that can be dynamically programmed to perform as either an n- or p-FET by applying appropriate gate potentials. In this work, an insulating 2D material, hexagonal boron nitride (hBN), is introduced as a gate dielectric and encapsulation layer around the nanowire in place of a thermally grown or atomic-layer-deposited oxide. hBN flake was mechanically exfoliated and transferred onto a silicon nanowire-based RFET device using the dry viscoelastic stamping transfer technique. The thickness of the hBN flakes was investigated by atomic force microscopy and transmission electron microscopy. The ambipolar transfer characteristics of the Si-hBN RFETs with different gating architectures showed a significant improvement in the device's electrical parameters due to the encapsulation and passivation of the nanowire with the hBN flake. Both n- and p-type characteristics measured through the top gate exhibited a reduction of hysteresis by 10-20 V and an increase in the on-off ratio (ION/IOFF) by 1 order of magnitude (up to 108) compared to the values measured for unpassivated nanowire. Specifically, the hBN encapsulation provided improved electrostatic top gate coupling, which is reflected in the enhanced subthreshold swing values of the devices. For a single nanowire, an improvement up to 0.97 and 0.5 V/dec in the n- and p-conduction, respectively, is observed. Due to their dynamic switching and polarity control, RFETs boast great potential in reducing the device count, lowering power consumption, and playing a crucial role in advanced electronic circuitry. The concept of mixed-dimensional RFET could further strengthen its functionality, opening up new pathways for future electronics.

Investigations towards incorporation of Eu3+ and Cm3+ during ZrO2 crystallization in aqueous solution.

Nuclear energy provides a widely applied carbon-reduced energy source. Following operation, the spent nuclear fuel (SNF), containing a mixture of radiotoxic elements such as transuranics, needs to be safely disposed of. Safe storage of SNF in a deep geological repository (DGR) relies on multiple engineered and natural retention barriers to prevent environmental contamination. In this context, zirconia (ZrO2) formed on the SNF rod cladding, could be employed as an engineered barrier for immobilization of radionuclides via structural incorporation. This study investigates the incorporation of Eu3+ and Cm3+, representatives for trivalent transuranics, into zirconia by co-precipitation and crystallization in aqueous solution at 80 °C. Complementary structural and microstructural characterization has been carried out by powder X-ray diffraction (PXRD), spectrum imaging analysis based on energy-dispersive X-ray spectroscopy in scanning transmission electron microscopy mode (STEM-EDXS), and luminescence spectroscopy. The results reveal the association of the dopants with the zirconia particles and elucidate the presence of distinct bulk and superficially incorporated species. Hydrothermal aging for up to 460 days in alkaline media points to great stability of these incorporated species after initial crystallization, with no indication of phase segregation or release of Eu3+ and Cm3+ over time. These results suggest that zirconia would be a suitable technical retention barrier for mobilized trivalent actinides in a DGR.

Exploring Antibacterial Activity and Bacterial-Mediated Allotropic Transition of Differentially Coated Selenium Nanoparticles.

The use of metal nanoparticles (NPs) as antimicrobial agents has become a promising alternative to the problem of antibiotic-resistant bacteria and other applications. Silver nanoparticles (AgNPs) are well-known as one of the most universal biocide compounds. However, selenium nanoparticles (SeNPs) recently gained more attention as effective antimicrobial agents. This study aims to investigate the antibacterial activity of SeNPs with different surface coatings (BSA-coated, chitosan-coated, and undefined coating) on the Gram-negative Stenotrophomonas bentonitica and the Gram-positive Lysinibacillus sphaericus in comparison to AgNPs. The tested NPs had similar properties, including shape (spheres), structure (amorphous), and size (50-90 nm), but differed in their surface charge. Chitosan SeNPs exhibited a positive surface charge, while the remaining NPs assayed had a negative surface charge. We have found that cell growth and viability of both bacteria were negatively affected in the presence of the NPs, as indicated by microcalorimetry and flow cytometry. Specifically, undefined coating SeNPs displayed the highest percentage values of dead cells for both bacteria (85-91%). An increase in reactive oxygen species (ROS) production was also detected. Chitosan-coated and undefined SeNPs caused the highest amount of ROS (299.7 and 289% over untreated controls) for S. bentonitica and L. sphaericus, respectively. Based on DNA degradation levels, undefined-SeNPs were found to be the most hazardous, causing nearly 80% DNA degradation. Finally, electron microscopy revealed the ability of the cells to transform the different SeNP types (amorphous) to crystalline SeNPs (trigonal/monoclinical Se), which could have environmentally positive implications for bioremediation purposes and provide a novel green method for the formation of crystalline SeNPs. The results obtained herein demonstrate the promising potential of SeNPs for their use in medicine as antimicrobial agents, and we propose S. bentonitica and L. sphaericus as candidates for new bioremediation strategies and NP synthesis with potential applications in many fields.

B20 Weyl Semimetal CoSi Film Fabricated by Flash-Lamp Annealing.

B20-CoSi is a newly discovered Weyl semimetal that crystallizes into a noncentrosymmetric crystal structure. However, the investigation of B20-CoSi has so far been focused on bulk materials, whereas the growth of thin films on technology-relevant substrates is a prerequisite for most practical applications. In this study, we have used millisecond-range flash-lamp annealing, a nonequilibrium solid-state reaction, to grow B20-CoSi thin films. By optimizing the annealing parameters, we were able to obtain thin films with a pure B20-CoSi phase. The magnetic and transport measurements indicate the appearance of the charge density wave and chiral anomaly. Our work presents a promising method for preparing thin films of most binary B20 transition-metal silicides, which are candidates for topological Weyl semimetals.

Leveraging Ligand and Composition Effects: Morphology-Tailorable Pt-Bi Bimetallic Aerogels for Enhanced (Photo-)Electrocatalysis.

Metal aerogels (MAs) are emerging porous materials displaying unprecedented potential in catalysis, sensing, plasmonic technologies, etc. However, the lack of efficient regulation of their nano-building blocks (NBBs) remains a big hurdle that hampers the in-depth investigation and performance enhancement. Here, by harmonizing composition and ligand effects, Pt- and Bi-based single- and bimetallic aerogels bearing NBBs of controlled dimensions and shapes are obtained by facilely tuning the metal precursors and the applied ligands. Particularly, by further modulating the electronic and optic properties of the aerogels via adjusting the content of the catalytically active Pt component and the semiconducting Bi component, both the electrocatalytic and photoelectrocatalytic performance of the Pt-Bi aerogels can be manipulated. In this light, an impressive catalytic performance for electro-oxidation of methanol is acquired, marking a mass activity of 6.4-fold higher under UV irradiation than that for commercial Pt/C. This study not only sheds light on in situ manipulating NBBs of MAs, but also puts forward guidelines for crafting high-performance MAs-based electrocatalysts and photoelectrocatalysts toward energy-related electrochemical processes.

Bimetallic Pt-Hg Aerogels for Electrocatalytic Upgrading of Ethanol to Acetate.

Electrochemical upgrading of ethanol to acetic acid provides a promising strategy to couple with the current hydrogen production from water electrolysis. This work reports the design of a series of bimetallic PtHg aerogels, where the PtHg aerogel exhibits a 10.5-times higher mass activity than that of commercial Pt/C toward ethanol oxidation. More impressively, the PtHg aerogel demonstrates nearly 100% selectivity toward the production of acetic acid. The operando infrared spectroscopic studies and nuclear magnetic resonance analysis verify the preferable C2 pathway mechanism during the reaction. This work opens an avenue for the electrochemical synthesis of acetic acid via ethanol electrolysis.

Presence of uranium(V) during uranium(VI) reduction by Desulfosporosinus hippei DSM 8344T.

Microbial U(VI) reduction influences uranium mobility in contaminated subsurface environments and can affect the disposal of high-level radioactive waste by transforming the water-soluble U(VI) to less mobile U(IV). The reduction of U(VI) by the sulfate-reducing bacterium Desulfosporosinus hippei DSM 8344T, a close phylogenetic relative to naturally occurring microorganism present in clay rock and bentonite, was investigated. D. hippei DSM 8344T showed a relatively fast removal of uranium from the supernatants in artificial Opalinus Clay pore water, but no removal in 30 mM bicarbonate solution. Combined speciation calculations and luminescence spectroscopic investigations showed the dependence of U(VI) reduction on the initial U(VI) species. Scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy showed uranium-containing aggregates on the cell surface and some membrane vesicles. By combining different spectroscopic techniques, including UV/Vis spectroscopy, as well as uranium M4-edge X-ray absorption near-edge structure recorded in high-energy-resolution fluorescence-detection mode and extended X-ray absorption fine structure analysis, the partial reduction of U(VI) could be verified, whereby the formed U(IV) product has an unknown structure. Furthermore, the U M4 HERFD-XANES showed the presence of U(V) during the process. These findings offer new insights into U(VI) reduction by sulfate-reducing bacteria and contribute to a comprehensive safety concept for a repository for high-level radioactive waste.

Localization and chemical speciation of europium(III) in Brassica napus plants.

For the reliable safety assessment of repositories of highly radioactive waste, further development of the modelling of radionuclide migration and transfer in the environment is necessary, which requires a deeper process understanding at the molecular level. Eu(III) is a non-radioactive analogue for trivalent actinides, which contribute heavily to radiotoxicity in a repository. For in-depth study of the interaction of plants with trivalent f elements, we investigated the uptake, speciation, and localization of Eu(III) in Brassica napus plants at two concentrations, 30 and 200 µM, as a function of the incubation time up to 72 h. Eu(III) was used as luminescence probe for combined microscopy and chemical speciation analyses of it in Brassica napus plants. The localization of bioassociated Eu(III) in plant parts was explored by spatially resolved chemical microscopy. Three Eu(III) species were identified in the root tissue. Moreover, different luminescence spectroscopic techniques were applied for an improved Eu(III) species determination in solution. In addition, transmission electron microscopy combined with energy-dispersive X-ray spectroscopy was used to localize Eu(III) in the plant tissue, showing Eu-containing aggregates. By using this multi-method setup, a profound knowledge on the behavior of Eu(III) within plants and changes in its speciation could be obtained, showing that different Eu(III) species occur simultaneously within the root tissue and in solution.