TY - CONF A1 - Matiushkina, Anna T1 - Synthesis and physical properties studies of bifunctional nanocomposites N2 - At present, the field of research on nanostructures is actively developing, which is due to their unique physico-chemical properties compared to bulk materials. Many research activities are focused on obtaining nanocomposites, which combine various types of nanostructures with different properties and function. For example, the development of magneto-luminescent nanocomposites makes it possible to use their luminescence for optical imaging, and their magnetic properties for magnetic targeted delivery and as agents of hyperthermia and magnetic resonance imaging. My master studies as part of the project Goszadanie 2019-1080 at ITMO were focused on the investigation of nanocomposites, consisting of semiconductor quantum dots (QDs) as luminescent component and superparamagnetic iron oxide nanoparticles (SPIONs) as magnetic one, in solution and during their incubation with HeLa cells. The spectrally resolved analysis of the QD photoluminescence (PL) kinetics of the free QDs and the QDs incorporated in these nanocomposites undergoing energy transfer processes allowed for (1) understanding the reasons for the quenching of QD luminescence in cells, (2) evaluating the average distance between the QDs and, based on this, concluding the degree of QD aggregation in cells, and (3) drawing conclusions about the QD-quencher composites integrity in cells. Overall, the analysis of the PL kinetics confirmed that QDs and SPIONs remain bound in the obtained nanocomposites during incubation with cells. To ensure the successful advancement of nanomaterials in biomedicine and the transition from their laboratory preparation and studies to their use in different applications and in industry, it is crucial to develop reliable measurement methods and reference materials candidates for the characterization of functional nanomaterials and assessing the quality of the obtained nanostructures. My recently started project at BAM, which is part of the EU metrology project MeTrINo, will be devoted to this topic. There we will focus on the development of methodologies for the synthesis and characterization of iron oxide nanoparticles, already used in biomedicine, and multi-element lanthanide-based nanoparticles with attractive upconversion luminescence, as reference materials with high monodispersity and reproducibility. Also, these nanoparticles will be functionalized with organic dyes for optical imaging and, probably, the study of the energy transfer phenomena. T2 - Bad Honnef Summer School CY - Bad Honnef, Germany DA - 30.07.2023 KW - Quantum dots KW - Iron oxide nanoparticles KW - Upconversion nanoparticles PY - 2023 AN - OPUS4-58075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osipova, Viktoriia T1 - Incorporation of near-infrared light emitting chromium (III) complexes into the core and shell of silica nanoparticles and optimisation of their optical properties N2 - In recent years, chromium (III) complexes have received a lot of attention as novel near-infrared (NIR) emitters. This interest was triggered by the report on the first molecular ruby Cr(ddpd)2(BF4)3 with a high photoluminescence quantum yield of 13.7% of its near infrared (NIR) emission band and a long luminescence lifetime of 1.122 ms at room temperature. Meanwhile, the influence of triplet oxygen, temperature, and pressure on the optical properties of different molecular rubies have been assessed. These features make these molecular rubies promising candidates for multi-analyte optical sensing applications and the generation of singlet oxygen for photocatalysis and photodynamic therapy. However, in an oxygen-containing environment, the photoluminescence quantum yields and luminescence lifetimes of these chromium(III) complexes show only very small values. This hampers their application as NIR luminescence labels. This application, that cannot be tackled by conventional deoxygenating approaches, requires suitable strategies to protect the luminescence of the chromium(III) complexes from oxygen quenching. Typical approaches to reduce the oxygen sensitivity of long-lived luminophores include the encapsulation into an oxygen-shielding matrix or less commonly employed, by tuning the bulkiness of the ligands for oxygen-sensitive coordination compounds. An elegant approach to reduce the undesired luminescence quenching by triplet oxygen explored by us presents the incorporation of these chromium(III) complexes into amorphous, non-porous silica nanoparticles, that can be simply surface functionalized, e.g., with targeting ligands and/or other sensor molecules. This can enable the use of such chromium(III) complexes as reporters for bioanalytical assays and bioimaging without the need to introduce reactive groups into the ligands and can pave the road to lifetime tuning. In this work, as first proof-of-concept experiments, a set of chromium (III) complexes constituting of different ligands and counter anions, were embedded into the core of silica nanoparticles. As an alternative synthesis strategy, selected complexes were incorporated into a silica shell formed around the core of self-made silica nanoparticles. Subsequently, the optical properties of the resulting luminescent silica nanoparticles were spectroscopically assessed by steady state and time-resolved luminescence spectroscopy. First results of time-resolved luminescence measurements of the Cr(ddpd)2(PF6)3 complex incorporated into 25nm large silica nanoparticles dispersed in aerated water in comparison to the decay kinetics obtained for this complex in acetonitrile in air showed an increase in lifetime from 46 µs to 1147 µs. This confirming our design concept of nanoscale NIR emissive Cr(III) reporters. T2 - Bad Honnef summer school CY - Bad Honnef, Germany DA - 30.07.2023 KW - Chromium (III) complexes KW - Silica Nanoparticles KW - Luminescence lifetime measurments PY - 2023 AN - OPUS4-58076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Habibimarkani, Heydar T1 - Investigating the Synergistic Effects of FeNi-Oxide Nanoparticles as Water Electrolysis Catalysts: A Multi-Technique Characterization Approach N2 - Electrocatalysis is and will continue to play a central role in the development of a new and modern sustainable economy, especially for chemicals and fuels. The storage of excess electrical energy into chemical energy by splitting water into hydrogen and oxygen is a feasible solution in this economic sector. A major drawback of electrical energy lies in the storage. Therefore, hydrogen is discussed as promising alternative. Fortunately, this issue can be effectively addressed through the implementation of chemical storage mechanisms. Due to their abundance on Earth and inherent stability in alkaline solutions, transition-metal oxides have become one of several viable alternatives to conventional noble-metal catalysts. Since FeNi oxide is one of the most active oxygen evolution reaction (OER) electrocatalysts for alkaline water electrolysis, it has been the subject of extensive research. A series of different types of FeNi oxide nanoparticles (NPs) with atomic ratios covering a broad range, and various sizes with specific stoichiometric and non-stoichiometric iron and nickel ratios was synthesized and characterized by the combination of surface analysis techniques, such as time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). The morphology was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed the coexistence of mixed and unmixed iron and nickel NPs with comparable sizes in the range of 30–40 nm across all ratios. The synthesis technique displayed control over the iron-nickel ratio, as evidenced by energy dispersive X-ray spectroscopy (EDS) data. The presence of magnetite (Fe3O4) was detected in all samples investigated by X-ray diffraction (XRD). Furthermore, the existence of nickel ferrite (NiFe2O4) was shown in the Fe2Ni by XRD analysis. For the cyclic voltammetry (CV) measurements, the NPs were deposited onto glassy carbon electrodes using Nafion® as an ionomer, and 1 M KOH was employed as the electrolyte. Subsequently, the NPs/Nafion® electrode was transferred into the ToF-SIMS chamber to allow surface analysis and depth profiling. The ToF-SIMS analysis revealed distinct peaks corresponding to Fe, Ni, and other peaks associated with Nafion®, whereas a straightforward correlation between the Ni.Fe ratio and the SIMS peak pattern is not possible. The catalytic activity towards OER was evaluated through CV measurements, where the Fe2Ni3 ratio exhibited the most favorable performance, displaying a lower overpotential. T2 - European Materials Research Society (E-MRS) Fall 2023 CY - Warsaw, Poland DA - 18.09.2023 KW - FeNi-Oxide NPs KW - ToF-SIMS KW - Catalysts KW - OER PY - 2023 AN - OPUS4-59139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Habibimarkani, Heydar T1 - Complementary Characterization of FeNi-Oxide Nanoparticles as Catalysts for Water Electrolysis combining Electron Microscopy, EDS, XRD, ToF-SIMS and Electrochemical Analysis N2 - Electrocatalysis is and will continue to play a central role in the development of a new and modern sustainable economy, especially for chemicals and fuels. The storage of excess electrical energy into chemical energy by splitting water into hydrogen and oxygen is a feasible solution in this economic sector. A major drawback of electrical energy lies in the storage. Therefore, hydrogen is discussed as promising alternative. Fortunately, this issue can be effectively addressed through the implementation of chemical storage mechanisms. Due to their abundance on Earth and inherent stability in alkaline solutions, transition-metal oxides have become one of several viable alternatives to conventional noble-metal catalysts. Since FeNi oxide is one of the most active oxygen evolution reaction (OER) electrocatalysts for alkaline water electrolysis, it has been the subject of extensive research. A series of different types of FeNi oxide nanoparticles (NPs) with atomic ratios covering a broad range, and various sizes with specific stoichiometric and non-stoichiometric iron and nickel ratios was synthesized and characterized by the combination of surface analysis techniques, such as time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). The morphology was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed the coexistence of mixed and unmixed iron and nickel NPs with comparable sizes in the range of 30–40 nm across all ratios. The synthesis technique displayed control over the iron-nickel ratio, as evidenced by energy dispersive X-ray spectroscopy (EDS) data. The presence of magnetite (Fe3O4) was detected in all samples investigated by X-ray diffraction (XRD). Furthermore, the existence of nickel ferrite (NiFe2O4) was shown in the Fe2Ni by XRD analysis. For the cyclic voltammetry (CV) measurements, the NPs were deposited onto glassy carbon electrodes using Nafion® as an ionomer, and 1 M KOH was employed as the electrolyte. Subsequently, the NPs/Nafion® electrode was transferred into the ToF-SIMS chamber to allow surface analysis and depth profiling. The ToF-SIMS analysis revealed distinct peaks corresponding to Fe, Ni, and other peaks associated with Nafion®, whereas a straightforward correlation between the Ni.Fe ratio and the SIMS peak pattern is not possible. The catalytic activity towards OER was evaluated through CV measurements, where the Fe2Ni3 ratio exhibited the most favorable performance, displaying a lower overpotential. T2 - SIMS Europe 2023 CY - Nottingham, England DA - 02.09.2023 KW - FeNi-Oxide NPs KW - ToF-SIMS KW - Catalysts KW - OER PY - 2023 AN - OPUS4-59143 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heilmann, Maria T1 - Size-Tunable Ni-Cu Core-Shell Nanoparticles: Structure, Composition, and Catalytic Activity N2 - Nanoparticles (NPs) have become important materials for a variety of chemical technologies, including catalysis. One of the main challenges is the reduction of green house gases, such as CO2. One opportunity besides the capturing is the conversion to synthesis gas via the reverse water-gas shift reaction. A facile and efficient method is described for the solvothermal synthesis of size-tunable, stable, and uniform NiCu core-shell NPs. The diameter of the NPs can be tuned in a range from 6 nm to 30 nm and the Ni:Cu ratio from 30:1 to 1:1. The NPs are structurally characterized with combination of transmission electron microscopy, anomalous small-angle X-ray scattering, X-ray photoelectron spectroscopy, and X-ray absorption fine structure. Using these analytical methods, a core-shell-shell structure their chemical composition is elucidated. A depletion from the core to the shell is observed, with the core consisting of NiCu alloy, surrounded by an inner Ni-rich shell and an outer NiO shell. The SiO2-supported NiCu core-shell NPs show pronounced selectivity of >99% for CO in the catalytic reduction of CO2 to CO using hydrogen as reactant (reverse water–gas shift reaction). T2 - Nanoalloys: recent developments and future perspectives Faraday Discussion CY - London, UK DA - 21.09.2022 KW - Nanoparticles KW - Core-shell KW - Catalysis PY - 2022 AN - OPUS4-56831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lauer, Franziska T1 - Multivariate statistics applied to MALDI-TOF MS data of pollen samples N2 - Current pollen screening information networks are based on time-consuming, microscopic determination of the genus-specific pollen morphology. Additionally, the given information relies on prediction of plant growth, wind direction and seasonal information. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was introduced for rapid analysis of complex biological samples. MALDI-TOF provides the possibility to measure species-specific mass peak patterns of pollen and offers a powerful tool for investigation of taxonomic relations. Our objective is to develop a fast, reliable, routine method for detecting single pollen grains in pollen mixtures. The obtained spectra are analyzed by multivariate statistics. T2 - 49. Jahrestagung der Deutschen Gesellschaft für Massenspektrometrie CY - Hamburg DA - 28.02.2016 KW - Pollen KW - Datenanalyse KW - Hauptkomponentenanalyse PY - 2016 AN - OPUS4-35523 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wurzler, Nina T1 - Chemical interaction mechanisms of metal reducing bacteria on steel surfaces N2 - Metal reducing bacteria (MRB) are able to utilize various materials such as iron, uranium and manganese as well as many organic compounds as electron acceptors. This process leads to the conversion of Fe(III) containing passive film species to soluble Fe(II) oxides and hydroxides. The reduction process triggers the acceleration of general and local corrosion processes. Electron transfer mechanisms are not yet fully understood. In literature it has been controversially discussed to which extend secreted electron shuttles contribute to the extracellular electron transfer (EET). To understand the chemical and electrochemical interaction mechanisms of MRB with steel surfaces this project combines a variety of in-situ techniques. The changes in oxide chemistry on Fe/steel surfaces in the presence of biomolecules and MRB are under investigation using a newly designed electrochemical cell for in situ XANES (x-ray absorption near edge structure) spectroscopy. Electrochemical quartz crystal microbalance (eQCM) studies support the spectroscopic investigations to gain information about the kinetics of attachment processes and changes in biofilm viscosity. The biofilm structure and composition as well as cell viability are investigated by complementary ex situ spectroscopic and microscopic analysis. Combining spectroscopic techniques and eQCM data with electrochemical measurements, biological processes and the resulting degradation of steel surfaces can be observed in a non-destructive manner. Selecting model systems and a defined biological medium allows the determination of individual effects of diverse surface and environmental parameters. The fundamental understanding of bacterial attachment mechanisms and initial steps of biofilm formation will contribute to the development of new antifouling strategies. T2 - 12th International Conference on Biology and Synchrotron Radiation CY - San Francisco, CA, USA DA - 21.08.2016 KW - Microbially influenced corrosion (MIC) KW - Metal reducing bacteria KW - XANES KW - Electrochemistry PY - 2016 AN - OPUS4-37238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Torge, Manfred T1 - Organic surface coatings on medieval stained glass and microbiological investigation N2 - Mediaeval stained glass has been treated with Polymethylmetacrylate coatings by Kwiatkowski in Poland during the 1950th. Such treated panels were found in the Johannis Church of Toruń (without protective glazing), in the Cathedral of Włocławek (behind a protective glazing), and on glass kept in exhibition cases in the museum of Toruń. Surface coatings have been detected and analyzed. There was no extensive contamination by fungi or bacteria if the glass was either coated or not. T2 - Glass Science in Art and Conservation 2017 CY - Lisbon, Portugal DA - 06.06.2017 KW - Microbiological investigation KW - Medieval stained glass KW - SEM analysis PY - 2017 AN - OPUS4-40573 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Torge, Manfred T1 - SEM and Micro-XRF analysis to investigate stained glass windows N2 - Several restoration projects of stained-glass windows have been performed in Poland since 2010.Chemical analysis of glass samples was performed with SEM/EDX on a FEI ESEM-XL 30, (EDX-EDAX) and with Micro-XRF (M4 Tornado, Bruker).The chemical composition of medieval glass samples and of glass samples of the 19th Century have been determined. T2 - Technart2017 CY - Bilbao, Spain DA - 02.05.2017 KW - SEM KW - Micro-XRF KW - Glass composition PY - 2017 AN - OPUS4-40435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea T1 - Microbial corrosion of iron coupled to methanogenesis by strains from different environments N2 - Microbially influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) which act upon the metal by the reactiveness of hydrogen sulfide, and by withdrawal of the available electrons in electrical contact with the metal. Methanogenic archaea are supposed to cause MIC. Because they do not produce hydrogen sulfide, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood. Precipitation of siderite (4Fe + 5HCO3 + 5H+  4FeCO3 + CH4 + 3H2O) can lead to an insulating layer on the metal surface and lower the corrosion rate. Still, the extent of FeCO3 precipitation may be significantly influenced by environmental conditions such as pH and advective processes. T2 - ISME CY - Leipzig, Germany DA - 12.08.2018 KW - Methanogens KW - MIC KW - Corrosion KW - Environmental Simulation PY - 2018 AN - OPUS4-46397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -