TY - JOUR A1 - Müller, Anja A1 - Heinrich, Thomas A1 - Tougaard, S. A1 - Werner, W. S. M. A1 - Hronek, M. A1 - Kunz, Valentin A1 - Radnik, Jörg A1 - Stockmann, Jörg M. A1 - Hodoroaba, Vasile-Dan A1 - Benemann, Sigrid A1 - Nirmalananthan-Budau, Nithiya A1 - Geißler, Daniel A1 - Sparnacci, K. A1 - Unger, Wolfgang T1 - Determining the thickness and completeness of the shell of polymer core-shell nanoparticles by X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and transmission scanning electron microscopy JF - The journal of physical chemistry C N2 - Core–shell nanoparticles (CSNPs) have become indispensable in various industrial applications. However, their real internal structure usually deviates from an ideal core–shell structure. To control how the particles perform with regard to their specific applications, characterization techniques are required that can distinguish an ideal from a nonideal morphology. In this work, we investigated poly(tetrafluoroethylene)–poly(methyl methacrylate) (PTFE–PMMA) and poly(tetrafluoroethylene)–polystyrene (PTFE–PS) polymer CSNPs with a constant core diameter (45 nm) but varying shell thicknesses (4–50 nm). As confirmed by transmission scanning electron microscopy (T-SEM), the shell completely covers the core for the PTFE–PMMA nanoparticles, while the encapsulation of the core by the shell material is incomplete for the PTFE–PS nanoparticles. X-ray photoelectron spectroscopy (XPS) was applied to determine the shell thickness of the nanoparticles. The software SESSA v2.0 was used to analyze the intensities of the elastic peaks, and the QUASES software package was employed to evaluate the shape of the inelastic background in the XPS survey spectra. For the first time, nanoparticle shell thicknesses are presented, which are exclusively based on the analysis of the XPS inelastic background. Furthermore, principal component analysis (PCA)-assisted time-of-flight secondary-ion mass spectrometry (ToF-SIMS) of the PTFE–PS nanoparticle sample set revealed a systematic variation among the samples and, thus, confirmed the incomplete encapsulation of the core by the shell material. As opposed to that, no variation is observed in the PCA score plots of the PTFE–PMMA nanoparticle sample set. Consequently, the complete coverage of the core by the shell material is proved by ToF-SIMS with a certainty that cannot be achieved by XPS and T-SEM. KW - XPS KW - T-SEM KW - ToF-SIMS KW - Core-shell nanoparticles PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499165 DO - https://doi.org/10.1021/acs.jpcc.9b09258 VL - 123 IS - 49 SP - 29765 EP - 29775 PB - American Chemical Society CY - Washington, DC AN - OPUS4-49916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Riedel, Soraya A1 - Hülagü, Deniz A1 - Bennet, Francesca A1 - Carl, Peter A1 - Flemig, Sabine A1 - Schmid, Thomas A1 - Schenk, J. A. A1 - Hodoroaba, Vasile-Dan A1 - Schneider, Rudolf T1 - Electrochemical Immunomagnetic Ochratoxin A Sensing: Steps Forward in the Application of 3,3’,5,5’- Tetramethylbenzidine in Amperometric Assays JF - ChemElectroChem N2 - Electrochemical methods offer great promise in meeting the demand for user-friendly on-site devices for Monitoring important parameters. The food industry often runs own lab procedures, for example, for mycotoxin analysis, but it is a major goal to simplify analysis, linking analytical methods with smart technologies. Enzyme-linked immunosorbent assays, with photometric detection of 3,3’,5,5’-tetramethylbenzidine (TMB),form a good basis for sensitive detection. To provide a straightforward approach for the miniaturization of the detectionstep, we have studied the pitfalls of the electrochemical TMB detection. By cyclic voltammetry it was found that the TMB electrochemistry is strongly dependent on the pH and the electrode material. A stable electrode response to TMB could be achieved at pH 1 on gold electrodes. We created a smartphonebased, electrochemical, immunomagnetic assay for the detection of ochratoxin A in real samples, providing a solid basis forsensing of further analytes. KW - Ochratoxin A KW - Amperometry KW - Cyclic voltammetry KW - Electrochemistry KW - Immunoassay PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530421 DO - https://doi.org/10.1002/celc.202100446 N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S. VL - 8 IS - 13 SP - 2597 EP - 2606 AN - OPUS4-53042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mino, L. A1 - Pellegrino, F. A1 - Rades, Steffi A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Spotto, G. A1 - Maurino, V. A1 - Martra, G. T1 - Beyond shape engineering of TiO2 nanoparticles: Post-synthesis treatment dependence of surface hydration, hydroxylation, Lewis acidity and photocatalytic activity of TiO2 anatase nanoparticles with dominant {001} or {101} facets JF - ACS Applied Nano Materials N2 - TiO2 anatase nanoparticles are among the relevant players in the field of light-responsive semiconductor nanomaterials used to face environmental and energy issues. In particular, shape-engineered TiO2 anatase nanosheets with dominant {001} basal facets gained momentum because of the possibility to exploit different and/or improved functional behaviors with respect to usual bipyramidal TiO2 anatase nanoparticles, mainly exposing {101} facets. Nevertheless, such behavior depends in a significant extent on the physicochemical features of surfaces exposed by nanosheets. They can vary in dependence on the presence or removal degree of capping agents, namely, fluorides, used for shape-engineering, and experimental investigations in this respect are still a few. Here we report on the evolution of interfacial/ surface features of TiO2 anatase nanosheets with dominant {001} facets from pristine nanoparticles fluorinated both in the bulk and at their surface to nanoparticles with F− free surfaces by treatment in a basic solution and to totally F− free nanoparticles by calcination at 873 K. The nanoparticles fluorine content and its subsequent evolution is determined by complementary techniques (ion chromatography, TOF-SIMS, XPS, AES, SEM-EDX), probing different depths. In parallel, the evolution of the electronic properties and the Ti valence state is monitored by UV−vis spectroscopy and XPS. The calcination treatment results in {001} facets poorly hydroxylated, hydrated, and hydrophilic, which appear as surface features consequent to the expected (1 × 4) reconstruction. Moreover, IR spectroscopy of CO adsorbed as probe molecule indicates that the Lewis acidity of Ti4+ sites exposed on (1 × 4) reconstructed {001} facets of calcined TiO2 nanosheets is weaker than that of cationic centers on {101} facets of bipyramidal TiO2 anatase nanoparticles. The samples have also been tested in phenol photodegradation highlighting that differences in surface hydration, hydroxylation, and Lewis acidity between TiO2 nanoparticles with nanosheet (freed by F− by calcination at 873 K) and bipyramidal shape have a strong impact on the photocatalytic activity that is found to be quite limited for the nanoparticles mainly exposing (1 × 4) reconstructed {001} facets. KW - Nanoparticles KW - TiO2 KW - F- doping KW - Shape-controlled nanoparticles KW - Nanosheets PY - 2018 DO - https://doi.org/10.1021/acsanm.8b01477 SN - 2574-0970 VL - 1 IS - 9 SP - 5355 EP - 5365 PB - ACS Publications CY - Washington, DC, U.S.A. AN - OPUS4-46157 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rades, Steffi A1 - Oswald, F. A1 - Narbey, S. A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan T1 - Analytical approach for characterization of morphology and chemistry of a CH3NH3PbI3/TiO2 solar cell layered system JF - Surface and Interface Analysis N2 - Manufacturing of new perovskite layered solar cells with constant high light conversion Efficiency over time may be hampered by the loss of efficiency caused by structural and/or chemical alterations of the complex layered system. SEM/EDX combined with XPS were chosen as an appropriate methodical approach to characterize perovskite laboratory cells in depth and at surface, before and after light exposure. The layered perovskite system investigated here is based on glass covered with fluorine doped tin oxide, followed by thin films of TiO2, ZrO2, and a thick monolithic carbon. TiO2 film is subdivided into a dense layer covered by porous one constituted of nanoparticles of truncated bipyramidal shape. This layered system serves as the matrix for the perovskite. EDX spectral maps on cross sections of specimen have shown that Pb and I are distributed homogeneously throughout the porous layers C, ZrO2, and TiO2. SEM/EDX data show that 20 weeks of ambient daylight did not change significantly the in‐depth distribution of the elemental composition of Pb and I throughout the entire solar cell system. It was confirmed with EDX that nanoparticles identified in high‐resolution SEM micrographs contain mainly Pb and I, indicating these to be the perovskite crystals. However, a compositional and chemical altering began in the near‐surface region of the outermost ~10 nm after 2 months of illumination which was observed with XPS. T2 - ECASIA 2017 CY - Montpellier, France DA - 24.09.2017 KW - Solar Cell KW - SEM KW - EDX KW - XPS KW - layered system PY - 2018 DO - https://doi.org/10.1002/sia.6410 SN - 0142-2421 SN - 1096-9918 VL - 50 IS - 11 SP - 1234 EP - 1238 PB - John Wiley & Sons, Ltd. AN - OPUS4-46394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Pellegrino, F. A1 - Maurino, V. T1 - Morpho-Chemical Characterisation of Me-TiO2 Nanoparticles for Enhanced Photocatalytical Activity N2 - The conversion of solar energy into electricity and solar fuels is of crucial importance for a green and sustainable future. Water splitting using semiconductor photo-catalysts is considered a sustainable method to produce clean hydrogen (H2) fuel. Nevertheless, H2 photo-production efficiency remains still low, although extensive research works to understand better the mechanisms of the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) are being carried out. In this respect, TiO2 is a key photoactive material, usually employed with a co-catalyst deposited onto the surface to enhance charge carriers’ separation and catalyze surface charge transfer reactions. The deposition of a co-catalyst on the TiO2 nanoparticle surface represents one successful way to enhance the activity of the photocatalyst through a modification of its surface and redox properties. In this context, high-resolution scanning electron microscopy coupled with elemental analysis by energy-dispersive X-ray spectroscopy (EDS) is fundamental for studying and understanding the effect of the nanoparticle morphology on the functional properties of shape-controlled TiO2 crystals (bipyramides, platelets, and elongated particles). Different types of metal-semiconductor combinations, TiO2 shapes and dopant metals (Ag, Pt, etc) and metal concentrations will be discussed. T2 - ECASIA 2022 CY - Limerick, Ireland DA - 29.05.2022 KW - Titania nanoparticles KW - Photocatalysis KW - Scanning electron microscopy KW - Energy dispersive X-ray spectroscopy PY - 2022 AN - OPUS4-54977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nadejde, C. A1 - Neamtu, M. A1 - Schneider, Rudolf A1 - Hodoroaba, Vasile-Dan A1 - Ababei, G. A1 - Panne, Ulrich T1 - Catalytical degradation of relevant pollutants from waters using magnetic nanocatalysts JF - Applied Surface Science N2 - The catalytic efficiency of two magnetically responsive nanocatalysts was evaluated for the Degradation of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) azo dyes using hydrogen peroxide as oxidant undervery mild conditions (atmospheric pressure, room temperature). In order to obtain the nanocatalysts, thesurface of magnetite (Fe3O4) nanoparticles, prepared by a co-precipitation method, was further modified with ferrous oxalate, a highly sensitive non-hazardous reducing agent. The sensitized nanomaterials were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry, and used in the catalytic wet hydrogen peroxideoxidation (CWHPO) of RB5 and RY84, in laboratory-scale experiments. The effect of important variables such as catalyst dosage, H2O2 concentration, and contact time was studied in the dye Degradation kinetics. The results showed that it was possible to remove up to 99.7% dye in the presence of 20 mM H2O2 after 240 min of oxidation for a catalyst concentration of 10 g L−1at 25◦C and initial pH value of 9.0.CWHPO of reactive dyes using sensitized magnetic nanocatalysts can be a suitable pre-treatment methodfor complete decolorization of effluents from textile dyeing and finishing processes, once the Optimum operating conditions are established. T2 - 10th International Conference On Physics Of Advanced Materials (ICPAM-10) CY - Iasi, Romania DA - 22.09.2014 KW - Sensitized magnetic nanocatalysts KW - Catalytic wet peroxide oxidation KW - Reactive azo dye degradation PY - 2015 UR - http://www.sciencedirect.com/science/article/pii/S0169433215000483 DO - https://doi.org/10.1016/j.apsusc.2015.01.036 SN - 0169-4332 VL - 352 SP - 42 EP - 48 PB - Elsevier B.V. AN - OPUS4-38760 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nadejde, C. A1 - Neamtu, Mariana A1 - Hodoroaba, Vasile-Dan A1 - Schneider, Rudolf A1 - Ababei, G. A1 - Panne, Ulrich T1 - Characterization and application of Green Fenton-like catalysts for the removal of water pollutants T2 - PTIM 2015 Book of Proceedings N2 - Three types of magnetite-chitosan/iron oxalate/iron citrate nanoparticles (NP) were evaluated as magnetic heterogeneous catalysts for water treatment. T2 - PTIM 2015, 1st International Caparica Conference on Pollutant Toxic Ions and Molecules CY - Caparica, Portugal DA - 02.112015 KW - Bisphenol A degradation KW - Nanocatalysts KW - Characterization KW - Fenton oxidation KW - Wastewater PY - 2015 SN - 978-989-99361-6-4 SP - 186 EP - 187 PB - Proteomass AN - OPUS4-40082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rades, Steffi A1 - Oswald, F. A1 - Narbey, S. A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan T1 - Complementary methodical approach for the analysis of a perovskite solar cell layered system JF - Microscopy and Microanalysis N2 - Loss in efficiency of perovskite solar cells may be caused by structural and/or chemical alterations of the complex layered system. SEM/EDX combined with XPS were chosen as appropriate methodical approach to characterise perovskite laboratory cells in depth and complementary on top, before and after light exposure. The layered perovskite system investigated here is based on glass covered with fluorine doped tin oxide (FTO), followed by three porous thin films of TiO2, ZrO2 and a thick monolithic carbon. This layered system serves as the matrix for the perovskite. After infiltration of perovskite solution and annealing, EDX spectral maps on cross-sections of the specimen have been measured. The distribution of relevant elements – Si, Sn, Ti, Zr and C – correlates conclusively with layers visible in the acquired SEM images. Lead and iodine are distributed throughout the porous layers C, ZrO2 and TiO2. By EDX it was found that several weeks of ambient daylight did not change significantly the qualitative elemental composition of lead and iodine throughout the solar cell system. It was confirmed with EDX that nanoparticles identified in high-resolution SEM micrographs contain mainly Pb and I, indicating these to be the perovskite crystals. However, a time-dependent compositional and chemical altering was observed with XPS for the near-surface region of the outermost ~10 nm after two months of illumination. KW - Pervskite solar cells KW - TiO2 KW - Porous layer KW - SEM/EDX KW - XPS PY - 2017 UR - https://www.cambridge.org/core/services/aop-cambridge-core/content/view/0E9E937542BC8B5535900B53B7F667E9/S1431927617010558a.pdf/complementary_methodical_approach_for_the_analysis_of_a_perovskite_solar_cell_layered_system.pdf DO - https://doi.org/10.1017/S1431927617010558 VL - 23 IS - S1 (July) SP - 1978 EP - 1979 PB - Cambridge University Press CY - New York, NY, U.S.A. AN - OPUS4-41925 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Oswald, F. A1 - Narbey, S. A1 - Radnik, Jörg T1 - Time dependent Analysis of Morphology, Elemental and Chemical Composition of CH3NH3PbI3/TiO2 Solar Cell Layered System N2 - The motivation of this work is to produce thin films perovskite solar cells with constant high light conversion efficiency over time. Loss of efficiency may be caused by structural and/or chemical alterations of the complex layered system. As these changes might take place either in the bulk and/or on the surface of the stratified material, analytical tools addressing both key issues are selected and combined. SEM/EDS combined with XPS were chosen as appropriate methodical approach to characterise perovskite laboratory cells in depth and complementary on top, before and after light exposure. The layered perovskite system investigated here is based on glass covered with fluorine doped tin oxide (FTO), followed by three porous thin films of TiO2, ZrO2 and a thick monolithic carbon. The TiO2 film is subdivided into a dense layer covered by a porous one constituted of nanoparticles with a truncated bipyramidal shape. This layered system serves as the matrix for the perovskite. After infiltration of perovskite solution and annealing, EDS spectral maps on cross-sections of the specimen have been measured. The distribution of relevant elements – Si, Sn, Ti, Zr and C – correlates conclusively with layers visible in the acquired SEM images. Lead and iodine are distributed throughout the porous layers C, ZrO2 and TiO2. Specimens were exposed to ambient daylight for 7 weeks. In a SEM micrograph taken of the cross-section of a sample after illumination, the glass substrate and all layers FTO, TiO2, ZrO2 as well as C are clearly identified. EDS data have been acquired under the same measurement conditions as before the illumination. It was found that several weeks of ambient daylight did not change significantly the qualitative elemental composition of lead and iodine throughout the solar cell system. It was confirmed with EDS that nanoparticles identified in high-resolution SEM micrographs contain mainly Pb and I, indicating these to be the perovskite crystals. However, a time-dependent compositional and chemical altering was observed with XPS for the near-surface region of the outermost ~10 nm after 2 months of illumination. T2 - EMAS 2017 - 15th European Workshop on MODERN DEVELOPMENTS AND APPLICATIONS IN MICROBEAM ANALYSIS and IUMAS-7 Meeting CY - Konstanz, Germany DA - 07.05.2017 KW - Perovskite KW - Layer analytics KW - SEM/EDX KW - XPS KW - Solar cells PY - 2017 AN - OPUS4-40253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Oswald, F. A1 - Narbey, S. A1 - Radnik, Jörg T1 - Morphological and Chemical Composition of a CH3NH3PbI3/TiO2 Solar Cell Layered System N2 - Manufacturing of new perovskite layered solar cells with constant high light conversion efficiency over time may be hampered by the loss of efficiency caused by structural and/or chemical alterations of the complex layered system. SEM/EDX combined with XPS were chosen as an appropriate methodical approach to characterize perovskite laboratory cells in depth and at surface, before and after light exposure. The layered perovskite system investigated here is based on glass covered with fluorine doped tin oxide (FTO), followed by thin films of TiO2, ZrO2 and a thick monolithic carbon. TiO2 film is subdivided into a dense layer covered by porous one constituted of nanoparticles (NPs) of truncated bipyramidal shape. This layered system serves as the matrix for the perovskite. EDX spectral maps on cross-sections of specimen have shown that Pb and I are distributed homogeneously throughout the porous layers C, ZrO2 and TiO2. SEM/EDX data show that 20 weeks of ambient daylight did not change significantly the indepth distribution of the elemental composition of Pb and I throughout the entire solar cell system. It was confirmed with EDX that NPs identified in high-resolution SEM micrographs contain mainly Pb and I, indicating these to be the perovskite crystals. However, a compositional and chemical altering began in the near-surface region of the outermost ~10 nm after 2 months of illumination which was observed with XPS. T2 - 17th European Conference on Applications of Surface and Interface Analysis ECASIA 2017 CY - Montpellier, France DA - 24.09.2017 KW - Perovskite KW - Solar cells KW - SEM/EDX KW - XPS KW - Layer analysis PY - 2017 AN - OPUS4-42657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chemello, Giovanni A1 - Knigge, Xenia A1 - Ciornii, Dmitri A1 - Reed, B.P. A1 - Pollard, A.J. A1 - Clifford, C.A. A1 - Howe, T. A1 - Vyas, N. A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg T1 - Influence of the Morphology on the Functionalization of Graphene Nanoplatelets Analyzed by Comparative Photoelectron Spectroscopy with Soft and Hard X-Rays JF - Advance Materials Interfaces N2 - Since its isolation, graphene has received growing attention from academia and industry due to its unique properties. However, the “what is my material” barrier hinders further commercialization. X-ray photoelectron spectroscopy (XPS) is considered as a method of choice for the determination of the elemental and chemical composition. In this work the influence of the morphology of graphene particles on the XPS results is studied and investigated as a function of X-ray energy, using conventional XPS with Al K𝜶 radiation and hard X-ray photoemission spectroscopy (HAXPES) using Cr K𝜶 radiation. Thereby, the information depth is varied between 10 and 30 nm. For this purpose, two commercial powders containing graphene nanoplatelets with lateral dimensions of either ≈100 nm or in the micrometer range are compared. These larger ones exist as stack of graphene layers which is inspected with scanning electron microscopy. Both kinds of particles are then functionalized with either oxygen or fluorine. The size of the graphene particles is found to influence the degree of functionalization. Only the combination of XPS and HAXPES allows to detect the functionalization at the outermost surface of the particles or even of the stacks and to provide new insights into the functionalization process. KW - Functionalized graphene KW - Hard-energy X-ray photoelectron spectroscopy KW - X-ray photoelectron spectroscopy PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578860 DO - https://doi.org/10.1002/admi.202300116 SN - 2196-7350 SP - 1 EP - 8 PB - Wiley VCH AN - OPUS4-57886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ghasem Zadeh Khorasani, Media A1 - Elert, Anna Maria A1 - Hodoroaba, Vasile-Dan A1 - Agudo Jácome, Leonardo A1 - Altmann, Korinna A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Short- and long-range mechanical and chemical interphases caused by interaction of Boehmite (γ-AlOOH) with anhydride-cured epoxy resins JF - Nanomaterials N2 - Understanding the interaction between boehmite and epoxy and the formation of their interphases with different mechanical and chemical structures is crucial to predict and optimize the properties of epoxy-boehmite nanocomposites. Probing the interfacial properties with atomic force microscopy (AFM)-based methods, especially particle-matrix long-range interactions, is challenging. This is due to size limitations of various analytical methods in resolving nanoparticles and their interphases, the overlap of interphases, and the effect of buried particles that prevent the accurate interphase property measurement. Here, we develop a layered model system in which the epoxy is cured in contact with a thin layer of hydrothermally synthesized boehmite. Different microscopy methods are employed to evaluate the interfacial properties. With intermodulation atomic force microscopy (ImAFM) and amplitude dependence force spectroscopy (ADFS), which contain information about stiffness, electrostatic, and van der Waals forces, a soft interphase was detected between the epoxy and boehmite. Surface potential maps obtained by scanning Kelvin probe microscopy (SKPM) revealed another interphase about one order of magnitude larger than the mechanical interphase. The AFM-infrared spectroscopy (AFM-IR) technique reveals that the soft interphase consists of unreacted curing agent. The long-range electrical interphase is attributed to the chemical alteration of the bulk epoxy and the formation of new absorption bands. KW - Nanocomposites KW - Interphase KW - Intermodulation AFM KW - Electron microscopy KW - Infrared nano AFM PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483672 UR - https://www.mdpi.com/2079-4991/9/6/853/htm DO - https://doi.org/10.3390/nano9060853 SN - 2079-4991 VL - 9 IS - 6 SP - 853, 1 EP - 20 PB - MDPI AN - OPUS4-48367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nadejde, C. A1 - Neamtu, M. A1 - Hodoroaba, Vasile-Dan A1 - Schneider, Rudolf A1 - Ababei, G. A1 - Panne, Ulrich T1 - Hybrid iron-based core-shell magnetic catalysts for fast degradation of bisphenol A in aqueous systems JF - Chemical Engineering Journal N2 - Three types of hybrid modified magnetite (Fe₃O₄) nanoparticles, functionalized with either chitosan, chitosan/iron (II) oxalate or chitosan/iron (III) citrate, were synthesized by chemical precipitation method. The obtained nanomaterials were characterized by energy dispersive X-ray spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller analysis, scanning and Transmission electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The prepared composites were further tested as magnetic catalysts for the removal of bisphenol A (BPA) in aqueous media. The kinetic Degradation experiments were performed at laboratory scale, while the best operational parameters for all three materials were established: 1.00 g L⁻¹ of catalyst, 10 mmol L⁻¹ H₂O₂, under simulated solar light irradiation. After 15 min of UVA irradiation under the experimental conditions mentioned above, it was possible to decompose up to 99% of the micropollutant over all catalysts. Fe₃O₄/chitosan/iron oxalate catalyst showed the highest and fastest catalytic activity in BPA removal. Catalytic wet peroxide oxidation of non-biodegradable micropollutants on such iron-based hybrid nanoparticles can be a suitable pre-treatment method for wastewater decontamination, as an environment-friendly simplified Approach for water clean-up. KW - Katalysator KW - Bisphenol A KW - Nano KW - Fenton KW - Magnetische Nanopartikel PY - 2016 DO - https://doi.org/10.1016/j.cej.2016.05.090 SN - 1385-8947 VL - 302 SP - 587 EP - 594 PB - Elsevier CY - Amsterdam AN - OPUS4-37126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Singh, Chandan A1 - Riedel, Soraya A1 - Konthur, Zoltán A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg A1 - Schenk, J. A. A1 - Schneider, Rudolf T1 - Functionalized Ti3C2Tx nanosheets based biosensor for point-of-care detection of SARS-CoV‑2 antigen JF - ACS applied engineering materials N2 - MXenes are considered a promising class of two-dimensional materials with extraordinary physical and electrochemical properties. Distinguished features like high specific surface area and outstanding electrical conductivity make them suitable for electrochemical biosensing applications. Here, we report the development of a biosensor involving the functionalized MXene−titanium carbide nanosheets (Ti3C2Tx-NS) and monoclonal antibodies against the SARS-CoV-2 nucleocapsid protein (anti-SARS-CoV-2 mAb) to design a point-of-care device for detection of the SARS-CoV-2 nucleocapsid protein (SARS-CoV-2 NP) antigen. Few-layered titanium carbide nanosheets (denoted as FL-Ti3C2Tx-NS) have been synthesized using a single-step etching and delamination method and characterized using optical and electron microscopy techniques revealing the suitability for immunosensing applications. Binding studies revealed the excellent affinity between the biosensor and the SARS-CoV-2 NP. Electrochemical detection of SARS-CoV-2 NP is performed using differential pulse voltammetry and read by a smartphone-based user interface. The proposed FL-Ti3C2Tx-NS based biosensor offers the detection of SARS-CoV-2 NP with a limit of detection of 0.91 nM in a wide detection range in spiked saliva samples. Additionally, there is no cross-reactivity in the presence of potential interferants like SARS-CoV-2 spike glycoprotein and bovine serum albumin. These findings demonstrate the potential of MXenes in developing a rapid and reliable tool for SARS-CoV-2 NP detection. While we report the biosensing of SARS-CoV-2 NP, our system also paves the way for the detection of other SARS-CoV-2 antigens like spike protein or other biomolecules based on antigen−antibody interactions. KW - Antigen testing KW - Few-layered titanium carbide nanosheets KW - SARS-CoV-2 nucleocapsid protein KW - Label-free detection KW - Electrochemical immunosensor PY - 2023 DO - https://doi.org/10.1021/acsaenm.2c00118 SN - 2771-9545 N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S. VL - 1 IS - 1 SP - 495 EP - 507 PB - American Chemical Society CY - Washington, DC AN - OPUS4-56931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Jungnickel, H. A1 - Tentschert, J. A1 - Luch, A. A1 - Sogne, V. A1 - Maier, F. A1 - Burr, L. A1 - Schmid, D. A1 - Yoon, T.-H. A1 - Petters, R. A1 - Briffa, S.M. A1 - Valsami-Jones, E. T1 - Automation and Standardization—A Coupled Approach Towards Reproducible Sample Preparation Protocols for Nanomaterial Analysis JF - Molecules N2 - Whereas the characterization of nanomaterials using different analytical techniques is often highly automated and standardized, the sample preparation that precedes it causes a bottleneck in nanomaterial analysis as it is performed manually. Usually, this pretreatment depends on the skills and experience of the analysts. Furthermore, adequate reporting of the sample preparation is often missing. In this overview, some solutions for techniques widely used in nano-analytics to overcome this problem are discussed. Two examples of sample preparation optimization by au-tomation are presented, which demonstrate that this approach is leading to increased analytical confidence. Our first example is motivated by the need to exclude human bias and focuses on the development of automation in sample introduction. To this end, a robotic system has been de-veloped, which can prepare stable and homogeneous nanomaterial suspensions amenable to a variety of well-established analytical methods, such as dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), field-flow fractionation (FFF) or single-particle inductively coupled mass spectrometry (sp-ICP-MS). Our second example addresses biological samples, such as cells exposed to nanomaterials, which are still challenging for reliable analysis. An air–liquid interface has been developed for the exposure of biological samples to nanomaterial-containing aerosols. The system exposes transmission electron microscopy (TEM) grids under reproducible conditions, whilst also allowing characterization of aerosol composition with mass spectrometry. Such an approach enables correlative measurements combining biological with physicochemical analysis. These case studies demonstrate that standardization and automation of sample preparation setups, combined with appropriate measurement processes and data reduction are crucial steps towards more reliable and reproducible data. KW - Sample preparation KW - Automation KW - Nanomaterial analysis KW - Standardization PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543988 DO - https://doi.org/10.3390/molecules27030985 VL - 27 IS - 3 SP - 1 EP - 22 PB - MDPI AN - OPUS4-54398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Terborg, R. A1 - Kim, K.J. T1 - Elemental Composition and Thickness Determination of Thin Films by Electron Probe Microanalysis (EPMA) N2 - microscopy (AFM), or X-ray reflectometry. For the additional determination of thin film composition, techniques like X-ray photoelectron spectroscopy (XPS) or mass spectrometry-based techniques can be used. An alternative non-destructive technique is electron probe microanalysis (EPMA). This method assumes a sample of homogenous (bulk) chemical composition, so that it cannot be usually applied to thin film samples. However, in combination with the thin film software StrataGEM, the thickness as well as the composition of such films on a substrate can be determined. This has been demonstrated for FeNi on Si and SiGe on Al2O3 film systems. For both systems five samples with different elemental composition and a reference were produced and characterised by Korean research institute KRISS using inductively coupled plasma mass spectrometry (ICP-MS), Rutherford backscattering (RBS), and transmission electron microscopy (TEM). These samples were used for an international round robin test. In 2021, a new and open-source thin film evaluation programme called BadgerFilm has been released. It can also be used to determine thin film composition and thickness from intensity ratios of the unknown sample and standards (k-ratios). In this contribution, we re-evaluated the data acquired for the FeNi and SiGe systems using the BadgerFilm software package and compared the resulting composition and thickness with the results of the established StrataGEM software and other reference methods. With the current evaluation, the BadgerFilm software shows good agreement with the composition and thickness calculated by StrataGEM and as the reference values provided by the KRISS. T2 - ECASIA 2022 CY - Limerick, Ireland DA - 29.05.2022 KW - Thin films KW - Electron Probe Microanalysis KW - Interlaboratory Comparisons PY - 2022 AN - OPUS4-54963 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Oswald, F. A1 - Narbey, S. A1 - Radnik, Jörg T1 - Complementary methodical approach for the analysis of a perovskite solar cell layered system N2 - Loss in efficiency of perovskite solar cells may be caused by structural and/or chemical alterations of the complex layered system. As these changes might take place either in the bulk and/or on the surface of the stratified material, analytical tools addressing both key issues are selected and combined. SEM/EDX combined with XPS were chosen as appropriate methodical approach to characterise perovskite laboratory cells in depth and complementary on top, before and after light exposure. The layered perovskite system investigated here is based on glass covered with fluorine doped tin oxide (FTO), followed by three porous thin films of TiO2, ZrO2 and a thick monolithic carbon. The TiO2 film is subdivided into a dense layer covered by a porous one constituted of nanoparticles with a truncated bipyramidal shape. This layered system serves as the matrix for the perovskite. After infiltration of perovskite solution and annealing, EDX spectral maps on cross-sections of the specimen have been measured. The distribution of relevant elements – Si, Sn, Ti, Zr and C – correlates conclusively with layers visible in the acquired SEM images. Lead and iodine are distributed throughout the porous layers C, ZrO2 and TiO2. In a SEM micrograph taken of the cross-section of a sample after illumination, the glass substrate and all layers FTO, TiO2, ZrO2 as well as C are clearly identified. By EDX it was found that several weeks of ambient daylight did not change significantly the qualitative elemental composition of lead and iodine throughout the solar cell system. It was confirmed with EDX that nanoparticles identified in high-resolution SEM micrographs contain mainly Pb and I, indicating these to be the perovskite crystals. However, a time-dependent compositional and chemical altering was observed with XPS for the near-surface region of the outermost ~10 nm after two months of illumination. T2 - Microscopy & Microanalysis 2017 Meeting CY - St. Louis, MO, USA DA - 06.08.2017 KW - Thin films KW - EDX KW - XPS KW - SEM KW - Nanoparticles KW - Perovskite KW - TiO2 PY - 2017 AN - OPUS4-41664 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Radnik, Jörg A1 - Kersting, R. A1 - Hagenhoff, B. A1 - Bennet, Francesca A1 - Ciornii, Dmitri A1 - Nymark, P. A1 - Grafström, R. A1 - Hodoroaba, Vasile-Dan T1 - Reliable Surface Analysis Data of Nanomaterials in Support of Risk Assessment Based on Minimum Information Requirements JF - nanomaterials N2 - The minimum information requirements needed to guarantee high-quality surface Analysis data of nanomaterials are described with the aim to provide reliable and traceable Information about size, shape, elemental composition and surface chemistry for risk assessment approaches. The widespread surface analysis methods electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) were considered. The complete analysis sequence from sample preparation, over measurements, to data analysis and data format for reporting and archiving is outlined. All selected methods are used in surface analysis since many years so that many aspects of the analysis (including (meta)data formats) are already standardized. As a practical analysis use case, two coated TiO2 reference nanoparticulate samples, which are available on the Joint Research Centre (JRC) repository, were selected. The added value of the complementary analysis is highlighted based on the minimum information requirements, which are well-defined for the analysis methods selected. The present paper is supposed to serve primarily as a source of understanding of the high standardization level already available for the high-quality data in surface analysis of nanomaterials as reliable input for the nanosafety community. KW - Electron microscopy KW - X-ray photoelectron spectroscopy KW - Secondary ion mass spectrometry KW - Energy dispersive X-ray spectroscopy KW - Standardization PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522683 DO - https://doi.org/10.3390/nano11030639 VL - 11 IS - 3 SP - 639 PB - MDPI AN - OPUS4-52268 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abram, Sarah-Luise A1 - Mrkwitschka, Paul A1 - Thünemann, Andreas A1 - Radnik, Jörg A1 - Häusler, I. A1 - Bresch, Harald A1 - Hodoroaba, Vasile-Dan A1 - Resch-Genger, Ute T1 - Iron Oxide Nanocubes as a New Certified Reference Material for Nanoparticle Size Measurements JF - Analytical chemistry N2 - The rational design and increasing industrial use of nanomaterials require a reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry. This calls for nanoscale reference materials (nanoRMs) for the validation and standardization of commonly used characterization methods closely matching real-world nonspherical nano-objects. This encouraged us to develop a nonspherical nanoRM of very small size consisting of 8 nm iron oxide nanocubes (BAM-N012) to complement spherical gold, silica, and polymer nanoRMs. In the following, the development and production of this nanoRM are highlighted including the characterization by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) as complementary methods for size and shape parameters, homogeneity and stability studies, and calculation of a complete uncertainty budget of the size features. The determination of the nanocubes’ edge length by TEM and SAXS allows a method comparison. In addition, SAXS measurements can also provide the mean particle number density and the mass concentration. The certified size parameters, area equivalent circular diameter and square edge length, determined by TEM with a relative expanded uncertainty below 9%, are metrologically traceable to a natural constant for length, the very precisely known (111) lattice spacing of silicon. Cubic BAM-N012 qualifies as a certified nanoRM for estimating the precision and trueness, validation, and quality assurance of particle size and shape measurements with electron microscopy and SAXS as well as other sizing methods suitable for nanomaterials. The production of this new iron oxide nanocube RM presents an important achievement for the nanomaterial community, nanomaterial manufacturers, and regulators. KW - Certification KW - SAXS KW - Homogeneity KW - Nano KW - Particle KW - Iron oxide KW - Quality assurance KW - Reference material KW - Size KW - Electron microscopy KW - Stability KW - Shape PY - 2023 DO - https://doi.org/10.1021/acs.analchem.3c00749 SN - 0003-2700 VL - 95 IS - 33 SP - 12223 EP - 12231 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-58176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - López de Ipina, J.-M. A1 - Arevalillo, A. A1 - Martín, A. A1 - Caillard, B. A1 - Marcoulaki, E. A1 - Aguerre- Charol, O. A1 - van Duuren-Stuurman, B. A1 - Hodoroaba, Vasile-Dan A1 - Viitanen, A.-K. A1 - Witters, H. A1 - Vercauteren, S. A1 - Persson, K. A1 - Bard, D. A1 - Evans, G. A1 - Jensen, K.A. A1 - Himly, M. A1 - Scalbi, S. A1 - Papin, A. A1 - Le Bihan, O. A1 - Kanerva, T. A1 - Tirez, K. A1 - Frijns, E. A1 - Niga, P. A1 - Eleftheriadis, K. A1 - Travlos, A. A1 - Geppert, M. A1 - Himly, M. A1 - Radnik, Jörg A1 - Kuchenbecker, Petra A1 - Resch-Genger, Ute A1 - Fraboulet, I. A1 - Bressot, C. A1 - Rissler, J. A1 - Gaucher, R. A1 - Binotto, G. A1 - Krietsch, Arne A1 - Braun, A. A1 - Abenet, S. A1 - Catalan, J. A1 - Verstraelen, S. A1 - Manier, N. A1 - Manzo, S. A1 - Fransman, S. A1 - Queron, J. A1 - Charpentier, D. A1 - Taxell, D. A1 - Säämänen, A. A1 - Brignon, J.-M. A1 - Jovanovic, A. A1 - Bisson, M A1 - Neofytou, P. T1 - EC4Safenano - Catalogue of Services N2 - The publicly available document encapsulates the first version of the Catalogue of Services of the future EC4Safenano Centre (CoS 2019). The CoS 2019 is structured in 12 Service Categories and 27 Service Topics, for each of the 12 categories considered. This architecture configures a 12 x 27 matrix that allows ordering the potential EC4Safenano offer in 324 types of services/groups of services. Each type of service/group of services is described, in a simple and friendly way, by means of a specific service sheet: the EC4Safenano - Service Data Sheet (EC4-SDS). These EC4-SDSs allow structuring and summarizing the information of each service, providing the customer with a concise view of characteristics of the service and also the contact details with the service provider. The CoS 2019 deploys a map of services consisting of a set of 100 EC4-SDSs, covering 7 of the 12 Service Categories and 17 of the 27 Service Topics. The harmonization of services is visualized as a future necessary step in EC4Safenano, in order to strengthen the offer and provide added value to customers with a growing offer of harmonized services in future versions of the CoS. The information contained in this document is structured in 3 main sections, as follows: • Catalogue structure. This section describes in short the main characteristics of the CoS 2019. • Catalogue content. This section represents the core part of the document and encapsulates the set of 100 SDSs displaying the offer proposed by the CoS 2019. • Online Catalogue. This section describes the resources implemented by EC4Safenano to facilitate the on-line consultation of the CoS 2019 by customers and other interested parties. KW - Nano-safety KW - Analytical services KW - Nanomaterials KW - Catalogue of services KW - EC4SafeNano KW - European Centre PY - 2021 UR - https://ec4safenano.eu-vri.eu/Public/Guidance SP - 1 EP - 72 PB - EU-VRi – European Virtual Institute for Integrated Risk Management CY - Stuttgart, Germany AN - OPUS4-52943 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg T1 - Minimale Anforderungen an Referenzdaten anhand von Beispielen aus der Elektronenmikroskopie und Oberflächenanalytik N2 - In dem Vortrag werden, anhand ausgewählten Beispielen aus der Elektronenmikroskopie und Oberflächenanalytik (EDX und XPS), die minimalen Anforderungen an Referenzdaten für zuverlässige und reproduzierbare Ergebnisse (z.B. Partikelgrößenverteilung, Elementzusammensetzung) vorgestellt und diskutiert. T2 - Workshop "Referenzdaten" CY - Berlin, Germany DA - 13.03.2020 KW - Referenzdaten KW - Nanopartikel KW - Elektronenmikroskopie KW - Oberflächenanalytik KW - Standardarbeitsanweisung KW - SOP KW - Standardisierung PY - 2020 AN - OPUS4-50571 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Radnik, Jörg A1 - Chemello, Giovanni A1 - Knigge, Xenia A1 - Al-Sabbgh, Dominik A1 - Hodoroaba, Vasile-Dan T1 - XPS, HAXPES, XRD and SEM datasets of functionalized graphene nanoplateletes N2 - The datasets from (Hard Energy) X-ray photoelectron spectroscopy, X-ray diffraction and Scanning Electron Microsopy are related to the publication G. Chemello, X. Knigge, D. Ciornii, B.P. Reed, A.J. Pollard, C.A. Clifford, T. Howe, N. Vyas, V.-D. Hodoroaba, J. Radnik "Influence of the morphology on the functionalization of graphene nanoplatelets analyzed by comparative photoelectron spectroscopy with soft and hard X-rays" Advanced Materials Interfaces (2023), DOI: 10.1002/admi.202300116. KW - Graphene related 2D materials KW - X-ray photoelectron spectroscopy KW - Hard-energy X-ray photoelectron spectroscopy KW - Scanning electron microscopy KW - Powder X-ray diffraction PY - 2023 DO - https://doi.org/10.5281/zenodo.7956497 PB - Zenodo CY - Geneva AN - OPUS4-57898 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neamtu, Mariana A1 - Nadejde, C. A1 - Hodoroaba, Vasile-Dan A1 - Schneider, Rudolf A1 - Ababei, G. A1 - Panne, Ulrich T1 - Photocatalysis of γ-cyclodextrin-functionalised Fe3O4 nanoparticles for degrading Bisphenol A in polluted waters JF - Environmental Chemistry N2 - The efficiency, relatively low cost and eco-friendly nature of hydrogen peroxide-assisted photocatalysis treatment procedures are significant advantages over conventional techniques for wastewater remediation. Herein, we evaluate the behaviour of g-cyclodextrin (g-CD) immobilised on either bare or chitosan (CS)–functionalised Fe3O4 nanoparticles, for photodegrading Bisphenol A (BPA) in ultrapure water and in real wastewater samples. The BPA removal efficiencies with Fe3O4/g-CD and Fe3O4/CS/g-CD were compared with those of Fe3O4/b-CD, and were monitored under UVA irradiation at near-neutral pH. The addition of H2O2 at low concentrations (15 mmol L-1) significantly increased BPA photodegradation in the presence of each nanocomposite. The highest catalytic activity was shown by both Fe3O4/g-CD and Fe3O4/CS/g-CD nanocomposites (,60 and 27%BPA removal in ultrapure water and real wastewater effluent, respectively). Our findings reveal the superior performance of g-CD-functionalised Fe3O4 relative to that of Fe3O4/b-CD. The use of CD-based nanocomposites as photocatalytic materials could be an attractive option in the pre- or post-treatment stage of wastewaters by advanced oxidation processes before or after biological treatment. KW - Photooxidation KW - Sonochemical synthesis KW - Wastewater PY - 2019 DO - https://doi.org/10.1071/EN18181 SN - 1448-2517 VL - 16 IS - 2 SP - 125 EP - 136 PB - CSIRO Publishing CY - Clayton South AN - OPUS4-48316 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nadejde, C. A1 - Neamtu, M. A1 - Hodoroaba, Vasile-Dan A1 - Schneider, Rudolf A1 - Paul, Andrea A1 - Ababei, G. A1 - Panne, Ulrich T1 - Tannic acid- and natural organic matter-coated magnetite as green Fenton-like catalysts for the removal of water pollutants JF - Journal of Nanoparticle Research N2 - The use of magnetic materials as heterogeneous catalysts has attracted increasing attention in the last years since they proved to be promising candidates for water treatment. In the present study, two types of surface-modified magnetite (Fe3O4) nanoparticles, coated with non-hazardous naturally occurring agents—either tannic acid (TA) or dissolved natural organic matter—were evaluated as magnetic heterogeneous catalysts. Chemical synthesis (co-precipitation) was chosen to yield the nanocatalysts due to its well-established simplicity and efficiency. Subsequently, the properties of the final products were fully assessed by various characterization techniques. The catalytic activity in heterogeneous oxidation of aqueous solutions containing a model pollutant, Bisphenol A (BPA), was comparatively studied. The effect of operational parameters (catalyst loading, H2O2 dosage, and UV light irradiation) on the Degradation performance of the oxidation process was investigated. The optimum experimental parameters were found to be 1.0 g/L of catalysts and 10 mM H2O2, under UV irradiation. The highest mineralization rates were observed for Fe3O4-TA catalyst. More than 80 % of BPA was removed after 30 min of reaction time under the specified experimental conditions. The obtained results showed that the two catalysts studied here are suitable candidates for the removal of pollutants in wastewaters by means of heterogeneous reaction using a green sustainable treatment method. KW - Nanocatalysts KW - Photo-Fenton oxidation KW - Wastewater KW - Bisphenol A degradation KW - Environment KW - Mitigation PY - 2015 UR - http://link.springer.com/article/10.1007/s11051-015-3290-0 DO - https://doi.org/10.1007/s11051-015-3290-0 VL - 17 IS - 12 SP - 476 (1) EP - 476 (10) PB - Springer AN - OPUS4-38758 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neamtu, Mariana A1 - Nadejde, C. A1 - Hodoroaba, Vasile-Dan A1 - Schneider, Rudolf A1 - Verestiuc, L. A1 - Panne, Ulrich T1 - Functionalized magnetic nanoparticles: Synthesis, characterization, catalytic application and assessment of toxicity JF - Scientific Reports N2 - Cost-effective water cleaning approaches using improved Treatment technologies, for instance based on catalytic processes with high activity catalysts, are urgently needed. The aim of our study was to synthesize efficient Fenton-like photo-catalysts for rapid degradation of persistent organic micropollutants in aqueous medium. Iron-based nanomaterials were chemically synthesized through simple procedures by immobilization of either iron(II) oxalate (FeO) or iron(III) citrate (FeC) on magnetite (M) nanoparticles stabilized with polyethylene glycol (PEG). Various investigation techniques were performed in order to characterize the freshly prepared catalysts. By applying advanced oxidation processes, the effect of catalyst dosage, hydrogen peroxide concentration and UV-A light exposure were examined for Bisphenol A (BPA) conversion, at laboratory scale, in mild conditions. The obtained results revealed that BPA degradation was rapidly enhanced in the presence of low-concentration H2O2, as well as under UV-A light, and is highly dependent on the surface characteristics of the catalyst. Complete photo-degradation of BPA was achieved over the M/PEG/FeO catalyst in less than 15 minutes. Based on the catalytic performance, a hierarchy of the tested catalysts was established: M/PEG/FeO > M/PEG/FeC > M/PEG. The results of cytotoxicity assay using MCF-7 cells indicated that the aqueous samples after treatment are less cytotoxic. KW - Bisphenol A KW - Magnetic nanocatalyst KW - Endocrine disruptor KW - Nanoparticle KW - Photodegradation KW - Fenton PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448297 DO - https://doi.org/10.1038/s41598-018-24721-4 SN - 2045-2322 VL - 8 SP - Article 6278, 1 EP - 11 PB - Springer Nature CY - London AN - OPUS4-44829 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Anja A1 - Heinrich, Thomas A1 - Tougaard, S. A1 - Werner, W. S. M. A1 - Hronek, M. A1 - Kunz, Valentin A1 - Radnik, Jörg A1 - Stockmann, Jörg M. A1 - Hodoroaba, Vasile-Dan A1 - Benemann, Sigrid A1 - Nirmalananthan-Budau, Nithiya A1 - Geißler, Daniel A1 - Sparnacci, K. A1 - Unger, Wolfgang T1 - Correction to "Determining the thickness and completeness of the shell of polymer core-shell nanoparticles by X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and transmission scanning electron microscopy" T2 - The journal of physical chemistry C N2 - This is a corrigendum to the original article "Determining the thickness and completeness of the shell of polymer core-shell nanoparticles by X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and transmission scanning electron microscopy" that was published in "The journal of physical chemistry C", vol. 123 (2019), no. 49 pp. 29765-29775. PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505451 DO - https://doi.org/10.1021/acs.jpcc.0c00027 SN - 1932-7447 SN - 1932-7455 VL - 124 IS - 6 SP - 3923 PB - American Chemical Society CY - Washington, DC AN - OPUS4-50545 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neamtu, M. A1 - Nadejde, C. A1 - Hodoroaba, Vasile-Dan A1 - Schneider, Rudolf A1 - Panne, Ulrich T1 - Singlet oxygen generation potential of porphyrin-sensitized magnetite nanoparticles: Synthesis, characterization and photocatalytic application JF - Applied Catalysis B: Environmental N2 - Singlet oxygen generation potential of two novel free-base-porphyrin photocatalysts was investigated. The freebase-porphyrin-sensitized Fe3O4 magnetic nanoparticles (MNPs) were tested for the degradation of the model pollutant Bisphenol A (BPA) in aqueous solution, for the first time. MNPs with either cubic or spherical shape were synthesized using the sonochemical approach, followed by sensitizing with photoactive 4,4′,4′′,4′′′- (Porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) (TCPP). The resulted photocatalysts were characterized in detail by scanning and transmission electron microscopy, Brunauer–Emmett–Teller analysis, spectral techniques and vibrating sample magnetometry. The electron spin resonance experiments have confirmed the high activity of the photocatalysts through the efficient formation of singlet oxygen in solution. The optimum operational parameters for BPA degradation were established as follows: 1.0 μmol L−1 BPA, 1.0 g L−1 of photocatalyst, 100 μmol L−1 H2O2, under UVA irradiation. In these conditions, the results for both photocatalysts revealed that after only 10 min of reaction, over 64% and ca. 90% of BPA have been removed from solution in the absence and presence of H2O2, respectively. Whereas after 60 minutes of treatment, only 24% of BPA in real wastewater effluent samples were removed under UVA irradiation in the absence of H2O2, showing the high complexity of real wastewater. Moreover, both photocatalysts were successfully used for BPA removal in three consecutive runs, without significant loss of catalytic features. KW - Bisphenol A KW - Magnetpartikel KW - Photooxidation KW - Singulettsauerstoff KW - TEM KW - SEM KW - Brunauer-Emmett-Teller KW - Katalysator KW - Abwasser KW - ESR PY - 2018 DO - https://doi.org/10.1016/j.apcatb.2018.03.079 SN - 0926-3373 VL - 232 SP - 553 EP - 561 PB - Elsevier B.V. CY - Amsterdam, NL AN - OPUS4-45267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ghasem Zadeh Khorasani, Media A1 - Silbernagl, Dorothee A1 - Szymoniak, Paulina A1 - Hodoroaba, Vasile-Dan A1 - Sturm, Heinz T1 - The effect of boehmite nanoparticles (gamma‐AlOOH) on nanomechanical and thermomechanical properties correlated to crosslinking density of epoxy JF - Polymer N2 - We show that complex physical and chemical interactions between boehmite nanoparticles and epoxy drastically affect matrix properties, which in the future will provide tuning of material properties for further optimization in applications from automotive to aerospace. We utilize intermodulation atomic force microscopy (ImAFM) for probing local stiffness of both particles and polymer matrix. Stiff particles are expected to increase total stiffness of nanocomposites and the stiffness of polymer should remain unchanged. However, ImAFM revealed that stiffness of matrix in epoxy/boehmite nanocomposite is significantly higher than unfilled epoxy. The stiffening effect of the boehmite on epoxy also depends on the particle concentration. To understand the mechanism behind property alteration induced by boehmite nanoparticles, network architecture is investigated using dynamic mechanical thermal analysis (DMTA). It was revealed that although with 15 wt% boehmite nanoparticles the modulus at glassy state increases, crosslinking density of epoxy for this composition is drastically low. KW - Crosslinking density KW - Epoxy KW - Intermodulation KW - Atomic force microscopy KW - Nanomechanical properties KW - Boehmite nanoparticles PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476050 DO - https://doi.org/10.1016/j.polymer.2018.12.054 SN - 0032-3861 SN - 1873-2291 VL - 164 SP - 174 EP - 182 PB - Elsevier AN - OPUS4-47605 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -