TY - CONF A1 - Ryll, Tom William T1 - Applied and Technical Mineralogy:� high-throughput automated platform for in-situ monitoring of CaSO4 formation N2 - In this project we investigate nucleation pathways by utilizing synchrotron-XRD and running a case-study on calcium sulfate and its polymorphs. To accomplish this, we developed a modular automation setup for reactions in solution to run synthesis and control reaction conditions. So far we successfully characterized the recycling process of gypsum (CaSO4*2H2O) and are now investigating the formation of anhydrite (CaSO4*0H2O) as well as possible applications for the automation setup and analysis. T2 - Geo4Göttingen 2025 CY - Göttingen, Germany DA - 14.09.2025 KW - Recycling KW - Gypsum KW - Synchrotron-X-ray-diffraction KW - Raman-spectroscopy KW - Automation PY - 2025 AN - OPUS4-64139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stolar, Tomislav T1 - Thermo mechanochemistry: merging heat and force for discovering new chemical transformations N2 - Mechanochemistry is a hot topic in chemistry, and the number of researchers from academia and industry joining the field is growing. Mechanical action drives chemical reactions forward independently of the solubility of reactants and drastically minimises solvent usage and waste production. Mechanochemistry also provides other advantages, such as faster reaction times, higher yields, altered selectivity, and access to products not obtainable by other methods. Furthermore, recent innovations in mechanochemistry enable conducting chemical reactions by combining force and heat in approach called thermo-mechanochemistry [1]. These conditions typically overcome high activation energies and access products not obtainable by mechanochemistry at ambient temperature conditions. In this talk, I will give an overview to this emerging topic and to our discoveries by thermo-mechanochemistry that include prebiotic peptide bond formation [2], synthesis of amide-based active pharmaceutical ingredient [3], condensation of diamondoid derivatives [4], and manipulation of polymorphic transition temperatures in organic molecular crystals [5]. T2 - Department Seminar at Newcastle University CY - Newcastle, UK DA - 15.09.2023 KW - Mechanochemistry PY - 2023 AN - OPUS4-62104 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stolar, Tomislav T1 - Sustainable mechanochemical reaction engineering: from molecular mechanisms to scalable technology N2 - In this talk, I will present about our quest to fundamentally understand mechanochemical reactions by in situ monitoring studies. Another of our interest is scaling up mechanochemistry. For example, we are now working on developing mechanochemical technology to enable a circular economy of plastics. T2 - Hokkaido International Workshop on Mechanochemistry CY - Hokkaido, Japan DA - 29.09.2024 KW - Mechanochemistry KW - Plastic recycling KW - Circular economy PY - 2024 AN - OPUS4-62109 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stolar, Tomislav T1 - Grinding away plastic waste: enabling the circular economy of plastics N2 - Single-use plastics are causing plastic pollution, and less than 10% of plastic waste gets recycled globally. Most of it ends up in landfills or is being incinerated in a highly unsustainable manner. Plastic waste in the environment endangers ecosystems, and microplastics in babies raise alarming health concerns. Hence, one of the global priorities is circular economy for plastics which does not further exploit fossil fuel feedstocks. However, current technologies like mechanical recycling are inadequate, and innovative ones such as chemical recycling, i.e., converting plastics back to the starting monomers, are essential. For example, we can use the recycled monomers to make new plastics in a circular manner or upcycle them to other value-added functional materials. Here, I will present a sustainable technology we developed for the chemical recycling of polyethylene terephthalate (PET). PET represents 10% of global plastic production and dominates in plastic packaging. The technology relies on mechanochemistry (grinding) which uses mechanical action for the chemical breakdown of plastic polymers in an environmentally friendly way. The next step in our research is to use life cycle and techno-economic assessment to validate the sustainability and commercial viability of our technology with the goal of transferring it to real-world industrial application. T2 - Berlin PostDoc Day 2023 CY - Berlin, Germany DA - 02.11.2023 KW - Mechanochemistry KW - Plastic recycling KW - Circular economy PY - 2023 AN - OPUS4-62103 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stolar, Tomislav T1 - Breaking the wall of circular plastics economy N2 - Traditional mechanical recycling cannot process most plastic waste streams and most of the plastic waste currently goes to landfills or incineration. Chemical recycling is a promising technology to mitigate this but is hindered by high costs (due to high process temperatures and production of solvent waste). We developed a cost-efficient technology for chemical recycling of plastic waste that reduces greenhouse gas emissions and minimizes energy consumption. It is based on solvent-free mechanochemistry for depolymerization of plastic polymers at ambient conditions. T2 - Falling Walls Lab Berlin-Adlershof CY - Berlin, Germany DA - 21.09.2023 KW - Mechanochemistry KW - Recycling KW - Circular economy PY - 2023 AN - OPUS4-62101 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stolar, Tomislav T1 - Breaking the wall of circular plastics economy N2 - Traditional mechanical recycling cannot process most plastic waste streams and most of the plastic waste currently goes to landfills or incineration. Chemical recycling is a promising technology to mitigate this but is hindered by high costs (due to high process temperatures and production of solvent waste). We developed a cost-efficient technology for chemical recycling of plastic waste that reduces greenhouse gas emissions and minimizes energy consumption. It is based on solvent-free mechanochemistry for depolymerization of plastic polymers at ambient conditions. T2 - 2023 Falling Walls Science Summit CY - Berlin, Germany DA - 07.11.2023 KW - Mechanochemistry KW - Plastic recycling KW - Circular economy PY - 2023 AN - OPUS4-62102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wagner, Jan T1 - This is the Way: An Evidence Based Route to Phytic-acid-based Flame Retardant Poly(lactide acid) N2 - Main message: This study provides an evidence-based route to flame retard poly (lactide acid) (PLA) with phytic acid (Phyt)-based flame retardants (FR). Phyt was prepared with lignin (Lig) and expandable graphite (EG). Three amine salts (arginine (Arg), piperazine (Pip), melamine (Mel)) were also synthesized with Phyt. Findings include UL 94 V0 classification, limited oxygen index (LOI) = 43.7 vol% and reduced total heat released (THR), while molecular weight (MW) was not affected. Combinations lead to the most effective FR. Introduction: As demand for biobased polymers increases, biobased FRs remain scarce in the market. With 28 wt.% P, Phyt is promising to be a biobased FR, but Phyt efficiency as a FR needs to be improved. [1] Furthermore, as a strong acid, it esterifies and hydrolysis PLAs backbone. With the combinations proposed in this study, processability and MW in PLA compounds were untouched, while FR performance of Phyt was enhanced. Experimental: Compounds analyzed in this study were: PLA, PLA Lig, PLA EG, PLA PhytLig, PLA PhytEG, PLA Mel, PLA PhytArg, PLA PhytPip, PLA PhytMel, PLA PhytMel Lig and PLA PhytMel EG. Addition of Phyt based FR was 16.7 wt.%, Lig and EG 10wt.%. Compounds were processed with twin screw extrusion, injection molding and hot press. Analysis was done with size exclusion tomography, differential scanning calorimetry (DSC), tensile strength, cone calorimeter, UL 94, LOI and thermogravimetry analysis (TGA) combined with Fourier transformation infrared spectroscopy (FTIR). Residues were analyzed with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Results and Discussion: To synthesize the FR, Lig and Phyt (solved in water) were mixed and dried. A solid material formed, which was grinded and then compounded with PLA. The same was done with EG. Phyt + Arg/Pip/Mel FR materials were each titrated to a pH of ~4.5, since this pH is known to be least harmful for the PLA backbone. For PhytMel a salt precipitated. PhytPip and PhytArg were dried and a resin-like structure was obtained, which was grinded to a powder. The molar mass distribution of PLA PhytArg (10,000 g/mol – 600,000 g/mol) is similar to PLAs ranging from 15,000 g/mol – 600,000 g/mol. MW distribution from highest to lowest was PLA > PLA PhytArg > PLA PhytMel > PLA PhytMel EG > PLA PhytMel Lig > PLA PhytEG > PLA PhytLig > PLA PhytPip. The reaction between Phyt and Arg/Mel prevents MW decomposition of PLA through a reaction of P acid and NH2 groups. Tensile strength declined to 35.9 MPA for PLA PhytMel and 32.1 MPA for PLA PhytArg, compared to 51.4 MPA for PLA. DSC analysis revealed TG was not affected for the FR compounds: Phyt Lig/EG/Arg/Mel, compared to PLA. PLA PhytMel crystallinity 𝐾∆𝐻𝑐𝑐𝑐𝑐 was 30%, PLA PhytArg crystallinity was 50%, compared to PLA 𝐾∆𝐻𝑐𝑐 was 46%. Melting peaks were not affected in PLA Phyt Arg/Mel. Flammability investigations lead to results of LOI 25.8 vol%/ UL 94 V2 classification in PLA, PLA PhytArg LOI 43.7 vol%/ UL 94 V2, due to strong dripping as a cooling mode of action. [2] PLA PhytMel burned with intumescent char and LOI 38.2 vol%/ UL 94 V2 was measured. Due to strong melt dripping, PLA PhytPip reached UL 94 V0. TGA revealed increased residue for all FR compounds. When materials were combined in PLA PhytMel EG residue was maximized to 19.9 wt.% (600°C, 𝑁𝑁2 atmosphere). FTIR analysis revealed PO and PH stretching vibrations, indicating radical scavenging. Cone calorimeter investigations of PLA, PLA PhytPip and PLA PhytArg lead to a steep incline in HRR to peak heat release rate (pHRR). Values are provided in Table 1. PLA PhytMel containing compounds exhibited prolonged burning and protective layer. PLA PhytLig, PLA PhytEG, PLA Mel (pHRR >1000) were investigated but proved inferior to PLA PhytMel, PLA PhytMel Lig and PLA PhytMel EG. THR was reduced in all Phyt compounds. Intumescence was observed in all compounds except for PLA Lig, PLA PhytLig and PLA PhytMel Lig. PLA PhytMel EG proved as the most effective compound in fire testing with a firm, coherent and intumescent char structure. This study provides an understanding of Phyt as a FR. It systematically improves Phyts effectiveness and processability in PLA. This evidence T2 - 20th European Meeting on Fire Retardant Polymeric Materials (FRPM2025) CY - Madrid, Spain DA - 03.06.2025 KW - Polylactide acid KW - Intumescence KW - Phosphorous flame retardant KW - Phytic acid PY - 2025 AN - OPUS4-63395 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Manzoni, Anna Maria T1 - Effect of a mixed atmosphere H2O-O2-SO2 on the oxidation kinetics and phase formation on CrMnFeCoNi and CrCoNi N2 - The high-temperature corrosion behaviors of the equimolar CrCoNi medium- and CrMnFeCoNi high-entropy alloy were studied in a gas atmosphere consisting of a volumetric mixture of 10% H2O, 2% O2, 0.5% SO2, and 87.5% Ar at 800 °C for up to 96 h. Both alloys were initially single-phase fcc structured and showed a mean grain size of ~50 µm and a homogeneous chemical composition. The oxide layer thickness of the Cantor alloy CrMnFeCoNi increased linearly with exposure time while it remained constant at ~1 µm for CrCoNi. A Cr2O3 layer and minor amounts of (Co,Ni)Cr2O4 developed on CrCoNi while three layers were detected on the Cantor alloy. These layers were a thin and continuous chromium rich oxide layer at the oxide/alloy interface, a dense (Mn,Cr)3O4 layer in the center and a thick and porous layer of Mn3O4 and MnSO4 at the gas/oxide interface. Additionally, a few metal sulfides were observed in the CrMnFeCoNi matrix. These results were found to be in reasonable agreement with thermodynamic calculations. T2 - ICHEM 2023 CY - Knoxville, TN, USA DA - 18.06.2023 KW - High entropy alloys KW - Chemically complex alloys KW - Corrosion KW - Mixed gas atmosphere PY - 2023 AN - OPUS4-57776 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stawski, Tomasz T1 - Towards sustainable solution-driven recycling of gypsum N2 - Calcium sulfate hemihydrate (CaSO4ᐧ0.5H2O), also known as bassanite, has been used as a precursor to produce gypsum (dihydrate, CaSO4ᐧ2H2O) for various construction and decorative purposes since prehistoric times. The main route to obtain hemihydrate is a thermal treatment of gypsum at temperatures typically between 150 °C and 200 °C to remove some of the structural water. In this contribution, we introduce (Fig. 1) a more efficient and sustainable method (T < 100 °C) that enables the direct, rapid, and reversibly conversion of gypsum to bassanite using reusable high salinity aqueous solutions (brineswith c[NaCl] > 4 M). The optimum conditions for the efficient production of bassanite in a short time (< 5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the typical behaviour of the bassanite phase in low salt environments. Traditionally, hemihydrate is obtained through a solid state thermal treatment because bassanite is considered to be metastable with respect to gypsum and anhydrite in aqueous solutions, and therefore gypsum-to-bassanite conversion should not occur in water. Its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures is inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline structure for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios. T2 - RAL-SAS - UK Small angle scattering meeting 2025 CY - Oxford, United Kongdom DA - 16.06.2025 KW - Scattering KW - SAXS KW - Calcium sulfate KW - Gypsum PY - 2025 AN - OPUS4-64682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Manzoni, Anna Maria T1 - Corrosion in the Co-Cr-Fe-Ni high entropy alloy family N2 - While a lage amount of research on high entropy alloys is oriented towards mechanical properties and the microstructural improvement it is also necessary to keep an eye on the environment that potential application materials will be submitted to. The Co-Cr-Fe-Ni based high entropy family has shown great potential over the years of high entropy research and some candidate alloys are chosen for an insight into their corrosion behaviour. Several atmospheres are studied, i.e. O2, H2O, SO2 and a mix thereof in argon as well as synthetic air. Just as for classic alloys, the chromium is the most important element in terms of protection agains further corrosion. The addition of manganese, as in case of the “Cantor alloy” CrMnFeCoNi, overpasses Cr when it comes to oxygen affinity and thus counteracts the layer formation of Cr2O3. Even without Mn, a temperature chosen too high will also affect the formation of the chromium oxide layer and spall it off, annulling its protective potential. We can also observe how trace elements influence the layer formation. These effects and their mechanisms will be discussed for the alloys CrFeNi, CoCrNi, CrMnFeCoNi and variations of Al10Co25Cr8Fe15Ni36Ti6 using a combination of electron microscopy, thermodynamic calculations and x-ray diffraction. T2 - MRS-T International Conference CY - Hsinchu, Taiwan DA - 17.11.2023 KW - Corrosion KW - Scanning electron microscopy KW - Mixed gas atmosphere PY - 2023 AN - OPUS4-58980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stawski, Tomasz T1 - Towards sustainable solution-driven recycling of gypsum N2 - Gypsum (CaSO₄·2H₂O) is a crucial mineral across sectors such as construction, agriculture, and biomedicine. Despite its potentially full recyclability, a shortage looms due to limited mining in Europe and decreasing production of flue gas desulfurization (FGD) gypsum, a byproduct of coal power plants. With current EU consumption at 24 MT/a (17 MT mined, 7 MT FGD), a deficit of 10-35 MT/a is projected by the 2030s as CaSO₄ becomes a critical raw material [1]. Meanwhile, substantial CaSO₄ waste is produced in various industries (e.g., phosphogypsum, red gypsum), but its recycling remains limited (10% in Germany, 5% in the EU) due to contamination and separation challenges. This contribution introduces a sustainable, efficient wet-chemical method for converting gypsum to bassanite (CaSO₄·0.5H₂O), and thus recycling gypsum, under mild conditions (T < 100 °C) using reusable high-salinity aqueous solutions (brines with c[NaCl] > 4 M) [2]. The optimal conversion conditions (T > 80°C, c[NaCl] > 4 M) enable rapid (<5 min) and reversible transformation (Fig. 1). Upon cooling, gypsum re-forms, offering a temperature-dependent control over phase transition. Unlike conventional thermal dehydration (150-200 °C), this approach promotes the dissolution of gypsum, allowing contaminants to be separated via selective precipitation or adsorption. Additionally, the wet-chemical process facilitates the physical removal of impurities from gypsum matrices, making it advantageous for recycling gypsum waste from sources such as demolition or urban mining, where it is often mixed with other materials. Our approach presents a sustainable pathway for recovering high-purity bassanite from contaminated gypsum waste, aligning with EU goals for resource conservation and waste reduction. T2 - MaterialsWeek 2025 CY - Frankfurt am Main, Germany DA - 02.04.2025 KW - Gypsum KW - Calcium sulfate KW - Recycling PY - 2025 AN - OPUS4-64677 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stawski, Tomasz T1 - Towards circular economy of gypsum N2 - Gypsum (CaSO₄·2H₂O) is a crucial mineral across sectors such as construction, agriculture, and biomedicine. Despite its potentially full recyclability, a shortage looms due to limited mining in Europe and decreasing production of flue gas desulfurization (FGD) gypsum, a byproduct of coal power plants. With current EU consumption at 24 MT/a (17 MT mined, 7 MT FGD), a deficit of 10-35 MT/a is projected by the 2030s as CaSO₄ becomes a critical raw material [1]. Meanwhile, substantial CaSO₄ waste is produced in various industries (e.g., phosphogypsum, red gypsum), but its recycling remains limited (10% in Germany, 5% in the EU) due to contamination and separation challenges. This talk introduces a sustainable, efficient wet-chemical method for converting gypsum to bassanite (CaSO₄·0.5H₂O), and thus recycling gypsum, under mild conditions (T < 100 °C) using reusable high-salinity aqueous solutions (brines with c[NaCl] > 4 M) [2]. The wet-chemical process facilitates the physical removal of impurities from gypsum matrices, making it advantageous for recycling gypsum waste from sources such as demolition or urban mining, where it is often mixed with other materials. The approach presents a sustainable pathway for recovering high-purity bassanite from contaminated gypsum waste, aligning with EU goals for resource conservation and waste reduction. T2 - GFZ Interface Geochemistry Seminars Spring 2025 CY - Potsdam, Germany DA - 06.05.2025 KW - Calcium sulfate KW - Circular economy KW - Gypsum PY - 2025 AN - OPUS4-64681 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stawski, Tomasz T1 - Historical Plaster Formulations and Their Influence on Crystallographic Microstructure N2 - Historical plaster formulations offer valuable insights into advanced engineering in pre-modern cultures. This study examines two such gypsum-based recipes: Gach-e Koshteh from 14th-century Iran and Gesso Sottile from 15th-century Italy, both of which have unique characteristics and were essential for artistic and architectural decoration. By replicating these recipes in a laboratory setting, we demonstrate how traditional masters manipulated gypsum microstructure without additives to optimize the surface and mechanical properties of plaster for specific functional and artistic purposes. The Koshteh recipe involves intensive kneading during plaster hydration, which retards setting and produces a platelet-like crystal morphology with alignment of the {010} faces, resulting in a hydrophilic surface ideal for water-based wall paintings. Sottile, in contrast, relies on slow recrystallization in excess water, generating loosely packed, needle-like crystals with reduced wettability—suitable for oil-based painting and gilding. Using wide-angle X-ray scattering (WAXS), atomic force microscopy (AFM), and scanning electron microscopy (SEM), we reveal that the Koshteh recipe yields a denser, better-packed plaster with enhanced wettability, while the Sottile recipe forms larger, more loosely arranged crystals and a more hydrophobic surface. These findings underscore the ingenuity of historical materials engineering and offer valuable insights for modern conservation and sustainable restoration practices. T2 - Geo4Göttingen 2025 CY - Göttingen, Germany DA - 14.09.2025 KW - Plaster KW - Gypsum KW - Stucco KW - Cultural heritage PY - 2025 DO - https://doi.org/10.48380/4e5z-av91 AN - OPUS4-64685 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stawski, Tomasz T1 - Towards solution-driven recycling of gypsum N2 - Gypsum (CaSO₄·2H₂O) is a crucial mineral across sectors such as construction, agriculture, and biomedicine. Despite its potentially full recyclability, a shortage looms due to limited mining in Europe and decreasing production of flue gas desulfurization (FGD) gypsum, a byproduct of coal power plants. With current EU consumption at 24 MT/a (17 MT mined, 7 MT FGD), a deficit of 10-35 MT/a is projected by the 2030s as CaSO₄ becomes a critical raw material [1]. Meanwhile, substantial CaSO₄ waste is produced in various industries (e.g., phosphogypsum, red gypsum), but its recycling remains limited (10% in Germany, 5% in the EU) due to contamination and separation challenges. This contribution introduces a sustainable, efficient wet-chemical method for converting gypsum to bassanite (CaSO₄·0.5H₂O), and thus recycling gypsum, under mild conditions (T < 100 °C) using reusable high-salinity aqueous solutions (brines with c[NaCl] > 4 M) [2]. The optimal conversion conditions (T > 80°C, c[NaCl] > 4 M) enable rapid (<5 min) and reversible transformation. Upon cooling, gypsum re-forms, offering a temperature-dependent control over phase transition. Unlike conventional thermal dehydration (150-200 °C), this approach promotes the dissolution of gypsum, allowing contaminants to be separated via selective precipitation or adsorption. Additionally, the wet-chemical process facilitates the physical removal of impurities from gypsum matrices, making it advantageous for recycling gypsum waste from sources such as demolition or urban mining, where it is often mixed with other materials. T2 - Geo4Göttingen 2025 CY - Göttingen, Germany DA - 14.09.2025 KW - Calcium sulfate KW - Gypsum PY - 2025 DO - https://doi.org/10.48380/fhck-bv98 AN - OPUS4-64684 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sediqi, Salbin T1 - Electrocatalytic carbon dioxide reduction on electrodeposited multi principal element alloy (MPEA) catalysts N2 - The aim of this project is to develop novel noble metal free electrocatalysts that do not rely on critical minerals. We focus on Cu containing multi principal element alloys (MPEAs) improve the efficiency and selectivity of the CO 2 reduction reaction. In general, MPEAs consist of more than three elements that form solid solutions without intermetallic phases. The unique chemical composition and atomic level mixing introduces synergetic effects that play a critical role in electrocat alysis, especially in terms of selectivity. The nearly infinite combinations of elements that can be incorporated into MPEAs provide ample opportunities to tailor their functionality for various applications. This study presents the development of thin films based on CuNiZn MPEAs for CO 2 reduction reaction. The one step electrodeposition of CuNiZn gradient films was performed on carbon electrodes using a Hull cell under constant current or potential. The influence of pH, additives and current density or potential on the composition and mic rostructure of the films was characterized by scanning electron microscopy (SEM) and energy dispersive X ray spectroscopy (EDX). Atomic force microscopy (AFM) was used to study the topography and surface roughness of the CuNiZn films. The results indicate that the addition of ethylenediaminetetraacetic acid (EDTA) and citrate improves the uniformity and adhesion of the thin films. Electrochemical measurements, including cyclic voltammetry, linear sweep voltammetry, and impedance spectroscopy, were performed to investigate the electrocatalytic activity and corrosion resistance of CuNiZn thin films. The CuNiZn gradient films deposited in the Hull cell allow high throughput screening of the electrocatalytic activity. This approach has identified several compositions with high activity, selectivity and stability. Selected electrodeposited films were further processed to nanoparticles by means of pulsed laser ablation in liquids (PLAL). Further analysis thin film and nanoparticle electrocatalysts was performed with in line / at line product monitoring using a rotating disk electrode setup coupled to gas chromatography (GC) and high perform ance liquid chromatography (HPLC). The presentation will summarize the results of our screening study with few deep dives in selected compositions showing superior performance. T2 - ECASIA 2024 CY - Gothenburg, Sweden DA - 09.06.2024 KW - CCMat KW - Energy conversion KW - Electrodeposition KW - Electrocatalysis PY - 2024 AN - OPUS4-62632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heinekamp, Christian T1 - An Amorphous Lewis-acidic Zirconium Chloro Fluoride as HF Shuttle: C-F Bond Activation and Formation N2 - In this work, we successfully synthesized amorphous zirconium chloro fluoride (ZCF), which exhibits medium lewis acidity. In addition to investigating the local coordination sphere around the Zr atoms and the material properties, we were able to establish a catalytic behavior of ZCF in C-F bond activation reactions. We present a heterogeneous catalyst that performs dehydrofluorination of a fluoroalkane and consecutive hydrofluorination of an alkyne at room temperature. T2 - 23rd International Symposium on Fluorine Chemistry CY - Quebec City, Canada DA - 23.07.2023 KW - ZCF KW - Heterogeneous catalysis KW - C-F bond activation PY - 2023 AN - OPUS4-58053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heuser, Lina T1 - Silver diffusion in low-melting alkali zinc borate model glasses studied by means of SNMS, TEM and XAS N2 - In many late-breaking research fields as in photovoltaics, microelectronics, nuclear waste glasses or at least mirror glasses silver diffusion in glasses is relevant to the issues of high-level functionality and recycling. The present study is focused on silver diffusion in innovative, low-melting alkali zinc borate glasses (X2O-ZnO-B2O3, X = Li, Na, K, Rb) potentially usable for silver metallization-pastes in solar cells. The glasses were coated with a thin metallic silver layer and heat treatments in air and nitrogen close to Tg at 470 °C for 2 h were performed. After heat treatment under air and nitrogen atmospheres the coating thickness, measured by a white light interferometer, was about 1.8 µm thick. Silver depth profiles determined by means of secondary neutral mass spectrometry (SNMS) indicate the fastest silver diffusion to a depth of 3.5 µm for Li2O-ZnO-B2O3 (LZB) glass. Nevertheless, the influence of the different alkali ions on the silver diffusion is small. The oxygen availability determines the silver diffusion into the glasses. The oxygen promotes the oxidation of the silver layer enabling Ag+ to diffuse into the glass and to precipitate as Ag0. Both species were detected by x-ray absorption spectroscopy (XAS). The precipitated metallic silver particles in Na2O-ZnO-B2O3 (NZB) glass have a mean size of 5.9 nm ± 1.2 nm diameter, which was determined using transmission electron microscopy (TEM). Phase separation in zinc-rich and zinc-poor phases with a mean diameter of 75 nm ± 20 nm occurred in NZB glass after heat treatment. Ion diffusion of the glasses into the silver layer was suggested by EDX-line scans. T2 - 94. Glastechnische Tagung CY - Online meeting DA - 10.05.2021 KW - Silver diffusion KW - Alkali zinc borate glass KW - Metallic silver precipitates KW - Phase separation PY - 2021 AN - OPUS4-52861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Influence of Surface Chemistry and Size on the Stability of β-NaYF4:Yb,Er Nanocrystals in Various Environments N2 - The use of inorganic lanthanide-doped upconversion nanoparticles (UCNP) in bioimaging and cellular studies requires biocompatible particles. One possible cause of UCNP toxicity is the release of potentially harmful fluoride and lanthanide ions as revealed by dilution studies in aqueous environments, particularly under high dilution conditions. To address this issue, suitable surface coatings preventing such effects in combination with fast screening methods suited for online monitoring and in situ analyses are desired. Here we present systematic studies of differently sized β-NaYF4:Yb,Er UCNP stabilized with different surface coatings and hydrophilic ligands varying in binding strength to the particle surface in various aqueous environments at different temperatures and UCNP concentrations. The concentration of the fluoride and lanthanide ions released upon particle dissolution was quantified electrochemically with a fluoride ion-sensitive electrode and inductively coupled plasma optical emission spectrometry (ICP-OES) and monitored fluorometrically, thereby exploiting the sensitivity of the upconversion luminescence to changes in size and surface chemistry. Moreover, changes in surface chemistry were determined with X-Ray photoelectron spectroscopy (XPS). Based upon our results, we could derive optimum screening parameters for UCNP stability studies and determine conditions and coating procedures and ligands for enhancing UCNP stability in aqueous environments. T2 - UPCON2021 CY - Online meeting DA - 06.04.2021 KW - Fluorescence KW - Lifetime KW - Method KW - Quantification KW - Stability KW - Coating KW - Surface chemistry KW - Lanthanide KW - Fluoride KW - Electrochemistry KW - ICP-OES KW - Upconversion KW - Nano KW - Particle KW - Aging KW - Quality assurance KW - Mass spectrometry KW - XPS PY - 2021 AN - OPUS4-52411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abram, Sarah-Luise T1 - Monodisperse iron oxide nanoparticles as reference material candidate for particle size measurements N2 - In order to utilize and rationally design materials at the nanoscale the reliable characterization of their physico-chemical properties is highly important, especially with respect to the assessment of their environmental or biological impact. Furthermore, the European Commission’s REACH Regulations require the registration of nanomaterials traded in quantities of at least 1 ton. Powders or dispersions where 50% (number distribution) of the constituent particles have sizes ≤ 100 nm in at least one dimension are defined as nanomaterials. This creates a need for industrial manufacturers and research or analytical service facilities to reliably characterize potential nanomaterials. Currently, BAM is developing reference nanoparticles, which shall expand the scarce list of worldwide available nano reference materials certified for particle size distribution and will also target other key parameters like shape, structure, porosity or functional properties. In this respect, materials like iron oxide or titanium dioxide are considered as candidates to complement the already available silica, Au, Ag, and polystyrene reference nanoparticles. The thermal decomposition of iron oleate precursors in high boiling organic solvents can provide large quantities of iron oxide nanoparticles that can be varied in size and shape.[1, 2] The presence of oleic acid or other hydrophobic ligands as capping agents ensures stable dispersion in nonpolar solvents. Such monodisperse, spherical particles were synthesized at BAM and pre-characterized by electron microscopy (TEM, SEM including the transmission mode STEM-in-SEM) and dynamic light scattering comparing cumulants analysis and frequency power spectrum. 1. REACH regulations and nanosafety concerns create a strong need for nano reference materials with diverse properties. 2. Iron oxide nanoparticles are under development as new candidate reference material at BAM. 3. Narrow particle size distribution confirmed by light scattering and electron microscopy. T2 - Nanosafety 2020 CY - Online meeting DA - 05.10.2020 KW - Iron oxide nanoparticles KW - Reference material KW - Particle size KW - Electron microscopy KW - Nanoplattform PY - 2020 AN - OPUS4-52774 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Miliūtė, Aistė A1 - George, Janine A1 - Mieller, Björn A1 - Stawski, Tomasz T1 - ZrV2O7 negative thermal expansion (NTE) material N2 - Zirconium vanadate (ZrV2O7) is a well-known negative thermal expansion (NTE) material that exhibits significant isotropic contraction over a broad temperature range (~150°C < T < 800°C). Therefore, it can be used to create composites with controllable expansion coefficients and prevent thermal stress, fatigue, cracking, and deformation at interfaces. We implement interdisciplinary research to analyze such material. We study the influence of the synthesis methods and their parameters on the sample's purity, crystallinity, and homogeneity. Moreover, we implement ab initio-based vibrational computations with partially treated anharmonicity in combination with experimental methods to follow temperature-induced structural changes and rationalize the negative thermal expansion in this material, including the influence of the local structure disorder. T2 - SALSA Make and Measure Conference CY - Berlin, Germany DA - 13.09.2023 KW - NTE KW - Composites KW - TEM PY - 2023 AN - OPUS4-58367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -