TY - CONF A1 - de Oliveira Guilherme Buzanich, Ana T1 - The versatility of XAS@BAM for real-time in situ electrocatalysis in collaborative materials research N2 - With the global push toward sustainable energy technologies, the development of efficient and durable electrocatalysts has become a research priority. Real-time in situ studies are essential to understand the dynamic behavior of catalysts under operational conditions. X-ray absorption spectroscopy (XAS) offers a unique, element-specific probe of electronic and structural changes at the active sites of electrocatalysts during electrochemical reactions. At BAM, collaborative research efforts leverage the advanced capabilities of the BAMline at the Berlin Synchrotron BESSY-II to study electrocatalytic materials under realistic working conditions. As a dedicated materials research beamline, the BAMline enables in situ and operando XAS across different time and length scales, making it ideally suited for monitoring catalytic transformations in real time. This presentation highlights the analytical strengths and sample environments developed for electrochemical cells at BAM, showcasing their application to electrocatalysis for energy conversion (e.g., water splitting, CO₂ reduction). Emphasis will be placed on how these insights contribute to the rational design and real-time optimization of functional materials for a sustainable energy future. T2 - MATSUS Konferenz CY - Valencia, Spanien DA - 20.10.2025 KW - Operando KW - XAS KW - In situ KW - Electrocatalysis PY - 2025 AN - OPUS4-64493 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Faustino, Leandro A. A1 - de Angelis, Leonardo D. A1 - de Melo, Eduardo C. A1 - Farias, Giliandro A1 - dos Santos, Egon C. A1 - Miranda, Caetano R. A1 - Buzanich, Ana G. A1 - Torresi, Roberto M. A1 - de Oliveira, Paulo F.M. A1 - Córdoba de Torresi, Susana I. T1 - Urea synthesis by Plasmon-Assisted N2 and CO2 co-electrolysis onto heterojunctions decorated with silver nanoparticles N2 - The N2 + CO2 co-electrolysis to urea synthesis has become a promising alternative to the energy intensive traditional processes for urea production. However, there are still challenges in this approach, especially due to the competition with HER (Hydrogen Evolution Reaction) leading to low efficiency. Electrochemistry assisted by localized surface plasmon resonance (LSPR) using metal nanoparticles has been reported to enhance different electrochemical reactions. Here we report an electrochemical LSPR assisted urea synthesis using Ag nanoparticles (NPs) supported on BiVO4/BiFeO3 catalyst mechanochemically synthesized. The electrochemical experiments were performed under dark and upon plasmon excitation at the LSPR region of Ag NPs. Our results demonstrated that exciting in the LSPR range, urea yield rate and Faradic efficiency were considerably improved with reduced overpotential, 19.2 μmol h− 1 g− 1 and FE 24.4% at +0.1 V vs RHE compared to 9.6 μmol h− 1 g− 1 and FE 9.4% at − 0.2 V vs RHE under dark conditions. Further in situ FTIR-RAS experiments for mechanism investigation revealed the presence of N-H and C-N intermediates and the real effect of Ag plasmon excitation on HER and N2 + CO2 co-electrolysis. Theoretical calculations confirm the energy of the species involved in C-N coupling as well the role of the complex catalytic sites, which agrees with XAS measurements. KW - Plasmon-assited KW - XAS KW - Urea KW - Electrocatalysis PY - 2025 DO - https://doi.org/10.1016/j.cej.2025.163072 SN - 1385-8947 VL - 513 SP - 1 EP - 13 PB - Elsevier B.V. AN - OPUS4-65492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Moss, Caitlin T1 - Framework Materials for the Electrocatalytic Reduction of Nitrate to Ammonia N2 - The electrocatalytic reduction of nitrate to ammonia offers a sustainable alternative to the energy-intensive Haber-Bosch process while simultaneously addressing the pressing issue of nitrate pollution in water sources. Developing efficient catalysts for this reaction is therefore vital for both environmental remediation and green ammonia production. Framework materials such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and coordination polymers present an emerging class of electrocatalytic materials due to their high surface area, tunable porosity, and structural modularity. Their ability to incorporate diverse metal centers and functional groups makes them promising candidates for selective and efficient nitrate reduction. In order to change and improve catalytic properties, different synthesis strategies can be pursued, such as metal alloying or calcination under different conditions. To fully understand and optimize these materials, advanced characterization techniques are essential to correlate structural features with catalytic performance, alongside in-situ methods for real-time mechanistic insights. T2 - Tag der Chemie 2025 CY - Berlin, Germany DA - 03.07.2025 KW - Electrocatalysis KW - Electrochemisty KW - Framework Materials KW - Ammonia Synthesis KW - Nitrate Reduction PY - 2025 AN - OPUS4-63815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pérez Blanes, H. A1 - Ghiasi, P. A1 - Sandkühler, J. A1 - Yesilcicek, Yasemin A1 - Pentzien, Simone A1 - Conradi, Andrea A1 - Prinz, Carsten A1 - Al-Sabbagh, Dominik A1 - Thünemann, Andreas A1 - Özcan Sandikcioglu, Özlem A1 - Witt, Julia T1 - High CO2 reduction activity on AlCrCoCuFeNi multi-principal element alloy nanoparticle electrocatalysts prepared by means of pulsed laser ablation N2 - Noble metal-free nanoparticles (NPs) based on multi-principal element alloys (MPEAs) were synthesized using a one-step pulsed laser ablation in liquids (PLALs) method for the electrochemical reduction of CO2. Laser ablation was performed in pure water or poly-(diallyldimethylammonium chloride) (PDADMAC)-containing an aqueous solution of Al8Cr17Co17Cu8Fe17Ni33 MPEA targets. Transmission electron microscopy (TEM) measurements combined with energy dispersive X-ray (EDX) mapping were used to characterize the structure and composition of the laser-generated MPEA nanoparticles (MPEA-NPs). These results confirmed the presence of a characteristic elemental distribution of a core-shell phase structure as the predominant NP species. The electrocatalytic performance of the laser-generated MPEA-NPs was characterized by linear sweep voltammetry (LSV) demonstrating an enhanced electrocatalytic CO2 activity for PDADMAC-stabilized NPs. The findings of these investigations indicate that MPEAs have great potential to replace conventional, expensive noble metal electrocatalysts. KW - Multi-principal element alloys KW - Chemically Complex Materials KW - CCMat KW - Electrocatalysis KW - Carbon dioxide reduction KW - Pulsed laser ablation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594018 DO - https://doi.org/10.1016/j.jmrt.2023.05.143 VL - 24 SP - 9434 EP - 9440 PB - Elsevier BV AN - OPUS4-59401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sachse, René T1 - Operando electrochemical spectroscopic ellipsometry: Material properties of highly active mesoporous IrO IrOxfilms revealed under realistic OER conditions N2 - Rising energy demand and the impending climate change require the development of a sustainable, fossil-free fuel and chemical production on a global scale. Hydrogen production via water electrolysis will be a fundamental cornerstone in this endeavor. The activity and stability of respective electrode coatings strongly depends on the coating's properties, i.e. phase composition, crystallinity, electrical conductivity, accessible surface, wettability and many other factors. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physicochemical properties. However, those relations can be complex, and are strongly influenced also by the reaction environment. Hence, operando analysis of the catalyst material during catalysis at realistic potentials and current densities is highly desirable. Yet, many analytical techniques cannot be applied in liquid environments at realistic potentials and current densities. We propose environmental ellipsometric analysis in a dedicated electrochemical flow cell as a new method to evaluate gas evolution reactions operando under realistic working conditions. Figure 1 illustrates schematically the developed technique. Key factors to success are highly active model-type catalysts with template-controlled porosity, a suitable sample environment, a deep understanding of the spectroscopic method and respective model development, as well as concise cross validation with numerous other analytical techniques. The method was developed and validated by analyzing a calcination series (300 - 600°C) of mesoporous templated IrOx films ex-situ and operando under oxygen evolution reaction (OER) conditions. The employed environmental electrochemical spectroscopic ellipsometric analysis (ECSE) revealed during OER the change of optical and electronic properties, i.e. the dielectric functions (real ε1 and imaginary part ε2), electrical and electronic properties such as resistivity (ρ) and band-to-band transitions (p-d band transitions). Film thickness and porosity were validated by means of scanning electron microscopy (SEM), X-ray reflectometry (XRR) or ellipsometric porosimetry (EP), electrical and electronic properties by means of conductivity measurements, X-ray photoelectron spectroscopy (XPS) or UV-Vis-NIR absorption spectroscopy. The electronic structures of the catalysts from valence electron energy loss spectra (VEELS) derived from the real (ε1) and imaginary part (ε2) of the dielectric function from SE measurements reveal a direct correlation with electrochemical activities in OER. In the presentation reversible and irreversible potential-dependent changes of the catalyst properties during operation will be discussed along with the dynamics of gas formation, transport and dissolution at different potentials. T2 - 54. Jahrestreffen deutscher Katalytiker CY - Online meeting DA - 16.03.2021 KW - Spectroscopic ellipsometry KW - Electrocatalysis KW - Oxygen evolution reaction KW - Mesoporous iridium oxide films KW - Non-destructive operando analysis PY - 2021 AN - OPUS4-52928 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sachse, René A1 - Pfüger, Mika A1 - Velasco-Vélez, Juan-Jesús A1 - Sahre, Mario A1 - Radnik, Jörg A1 - Bernicke, Michael A1 - Bernsmeier, Denis A1 - Hodoroaba, Vasile-Dan A1 - Krumrey, Michael A1 - Strasser, Peter A1 - Kraehnert, Ralph A1 - Hertwig, Andreas T1 - Assessing optical and electrical properties of highly active IrOx catalysts for the electrochemical oxygen evolution reaction via spectroscopic ellipsometry N2 - Efficient water electrolysis requires highly active electrodes. The activity of corresponding catalytic coatings strongly depends on material properties such as film thickness, crystallinity, electrical conductivity, and chemical surface speciation. Measuring these properties with high accuracy in vacuum-free and nondestructive methods facilitates the elucidation of structure−activity relationships in realistic environments. Here, we report a novel approach to analyze the optical and electrical properties of highly active oxygen evolution reaction (OER) catalysts via spectroscopic ellipsometry (SE). Using a series of differently calcined, mesoporous, templated iridium oxide films as an example, we assess the film thickness, porosity, electrical resistivity, electron concentration, electron mobility, and interband and intraband transition energies by modeling of the optical spectra. Independently performed analyses using scanning electron microscopy, energy-dispersive X-ray spectroscopy, ellipsometric porosimetry, X-ray reflectometry, and absorption spectroscopy indicate a high accuracy of the deduced material properties. A comparison of the derived analytical data from SE, resonant photoemission spectroscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy with activity measurements of the OER suggests that the intrinsic activity of iridium oxides scales with a shift of the Ir 5d t2g sub-level and an increase of p−d interband transition energies caused by a transition of μ1-OH to μ3-O species. KW - Spectroscopic ellipsometry KW - Electrocatalysis KW - Oxygen evolution reaction KW - Mesoporous iridium oxide films KW - Non-destructive ambient analysis KW - Intrinsic OER activity KW - Complementary methodology and metrology PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516288 DO - https://doi.org/10.1021/acscatal.0c03800 SN - 2155-5435 VL - 10 IS - 23 SP - 14210 EP - 14223 PB - American Chemical Society AN - OPUS4-51628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmalz, Alina T1 - Framework Materials for the Electrocatalytic Reduction of Nitrate to Ammonia N2 - The electrocatalytic reduction of nitrate to ammonia offers a sustainable alternative to the energy-intensive Haber-Bosch process while simultaneously addressing the pressing issue of nitrate pollution in water sources. Developing efficient catalysts for this reaction is therefore vital for both environmental remediation and green ammonia production. Framework materials such as metal-organic frameworks (MOFs) or metalated covalent organic frameworks (COFs) present an emerging class of electrocatalytic materials due to their high surface area, tunable porosity, and structural modularity. Their ability to incorporate diverse metal centers and functional groups makes them promising candidates for selective and efficient nitrate reduction. In order to change and improve catalytic properties, different synthesis strategies can be pursued, such as metal alloying, doping or calcination. To fully understand and optimize these materials, advanced characterization techniques are essential to correlate structural features with catalytic performance, alongside in-situ methods for real-time mechanistic insights. T2 - 10th European Crystallography School CY - Ohrid, North Macedonia DA - 23.06.2025 KW - Electrocatalysis KW - Electrochemistry KW - Framework Materials KW - Ammonia Synthesis KW - Nitrate Reduction PY - 2025 AN - OPUS4-63846 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 - Sediqi, Salbin T1 - Synthesis and characterization of multi-principal element alloys (MPEAs) for electrocatalysis applications N2 - The aim of this project is the development of novel, noble metal-free electrocatalysts that do not rely on critical minerals. We focus on multi-principal element alloys (MPEAs), especially combinations involving Cu, to significantly enhance the efficiency of the CO2 reduction reaction. Generally, MPEAs consist of more than three elements, forming solid solutions without intermetallic phases. The unique disordered random structure introduces synergetic effects that play a critical role in electrocatalysis, particularly in terms of selectivity. The neraly-endless combinations of elements that can be incorporated in MPEAs offer ample opportunities to tailor its functionality for various applications. This study presents the development of thin films based on NiZnCu MPEAs for the CO2 reduction reaction. The one-step electrodeposition of NiZnCu films was performed on Cu substrates in a single bath using a Hull cell under constant current or potential. The influence of pH, additives and current density or potential on the composition and microstructure 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 NiZnCu films. The results indicate that the addition of ethylenediaminetetraacetic acid (EDTA) and citrate enhances the uniformity and adhesion of the thin films. Electrochemical measurements, including cyclic voltammetry, linear sweep voltammetry and impedance spectroscopy were conducted to study the electrocatalytic activity and the corrosion resistance of NiZnCu thin films. The NiZnCu gradient films deposited in the Hull cell enable high-throughput screening of the electrocatalytic activity. With this approach, multiple compositions showing high activity, selectivity and stability were identified. Further analysis with in line / at line product analysis was performed using a rotating disc electrode setup coupled to gas chromotography (GC) and high-performance liquid chromotography (HPLC). The presentation will summarize the results of our screening study with few deep-dives in selected compositions showing superior performance. T2 - eMRS 2024 Spring Meeting CY - Strasbourg, France DA - 27.05.2024 KW - CCMat KW - Energy conversion KW - Electrocatalysis PY - 2024 AN - OPUS4-62633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sediqi, Salmin T1 - Multi-principal element alloy nanoparticle (MPEA-NP) electrocatalysts prepared by pulsed laser ablation for electroreduction of CO2 N2 - Multi-principal element alloy (MPEA) nanoparticle electrocatalysts have the potential to provide a cost-effective and efficient alternative to noble metal electrocatalysts. The chemically complex nature and the high configurational entropy of MPEAs offer advantages in tailoring catalytic activity, product selectivity, and improved stability under harsh reaction conditions. Cu-containing bimetallic catalyst systems have already been demonstrated to lead to a significant increase in catalytic efficiency compared to monometallic systems. Thus, this project aims at the design of Cu-containing MPEAs and nanoparticle electrocatalysts for carbon dioxide reduction reaction. In this project, base alloys were prepared by means of arc melting with subsequent homogenization treatments and processed by pulsed laser ablation in water and organic solvents into high-purity nanoparticles. The nanoparticles were characterized by means of transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). Electrochemical testing was performed both on bulk alloy samples and nanoparticle film coated glassy carbon electrodes by means of cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Nanoparticle coated electrodes have been investigated by means of atomic force microscopy (AFM) and scanning kelvin probe force microscopy (SKPFM) to assure a homogeneous distribution on the electrode surface. The presentation will summarize our initial results on the electrocatalytic activity of Cu-MPEA system for carbon dioxide reduction. T2 - OPERANDO SPM 2023 CY - Berlin DA - 15.11.2023 KW - Chemically Complex Materials KW - CCMat KW - Electrocatalysis PY - 2023 AN - OPUS4-59402 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -